Patent Publication Number: US-11036775-B2

Title: Information recording system and information recording method

Description:
The present application is a continuation application based on International Patent Application No. PCT/JP2017/002706, filed on Jan. 26, 2017, the content of which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to an information recording system and an information recording method. 
     Description of Related Art 
     In general, sounds in scenes such as conferences and interviews are recorded and the recorded sounds are used thereafter. For example, minutes and articles can be created by reproducing sounds and creating text based on the sounds. With the development of sound recognition technology, it has also become possible to generate text from a sound using sound recognition software. 
     Conventional observation devices record only information of an object obtained by observing the object. The record of a situation at an observation site as well as the record of information obtained by observation is regarded to be important to promote the use of data and prevent fraud. For example, there are examples of a laboratory notebook of a researcher, findings of a doctor, a construction site deployment report, and the like as examples of the record of the situation at the observation site. Also, the declining birthrate and aging population and the shortage of skilled workers have become a problem in every field. For the skill succession and education, the importance of recording of an on-site situation is increasing more and more. It is possible to record a situation of an observation site in more detail by recording text based on a sound of an observer in addition to information of an object. Also, it is possible to efficiently extract the information of the object in a desired situation by searching text for a word representing the situation of the observation site. 
     On the other hand, technology for recording information of an object and a sound in association has been disclosed. For example, in the technology disclosed in Japanese Unexamined Patent Application, First Publication No. 2008-199079, the appearance of an object is imaged and a sound uttered by an operator during imaging is acquired. The acquired image of the object and the acquired sound of the operator are recorded in association. In the technology disclosed in Japanese Unexamined Patent Application, First Publication No. 2008-085582, an image and a sound associated therewith are transmitted from a camera to a server. The server converts the received sound into text and generates information to be added to the image on the basis of a conversion result. The server stores the received image in association with the information generated on the basis of the sound. 
     SUMMARY OF THE INVENTION 
     According to a first aspect of the present invention, an information recording system includes a sound acquisition unit, a sound processing unit, a recording unit, a keyword reception unit, a search unit, a reading unit, and a display unit. The sound acquisition unit acquires sound information based on a sound uttered by a user. The sound processing unit converts the sound information acquired by the sound acquisition unit into text information and generates at least one conversion candidate word corresponding to the sound in a process of converting the sound information into the text information. The recording unit records the text information and the conversion candidate word such that the text information and the conversion candidate word are associated with each other. The keyword reception unit receives a keyword. The search unit searches for the keyword received by the keyword reception unit in the text information and the conversion candidate word and extracts a word matching the keyword from words within the text information and the conversion candidate word. The reading unit reads the text information including a first part corresponding to the word matching the keyword and a second part other than the first part from the recording medium. The display unit displays the text information read by the reading unit such that the first part and the second part are able to be distinguished. 
     According to a second aspect of the present invention, an information recording system includes an object information acquisition unit, a sound acquisition unit, a sound processing unit, a recording unit, a keyword reception unit, a search unit, a reading unit, and a display unit. The object information acquisition unit acquires object information about an object. The sound acquisition unit acquires sound information based on a sound uttered by an observer who observes the object. The sound processing unit converts the sound information acquired by the sound acquisition unit into text information and generates at least one conversion candidate word corresponding to the sound in a process of converting the sound information into the text information. The recording unit records the object information, the text information, the conversion candidate word, and time point information on a recording medium such that the object information, the text information, the conversion candidate word, and the time point information are associated with each other. The time point information indicates a time point at which the object information was acquired and a time point at which the sound information that is a source of the text information was acquired. The keyword reception unit receives a keyword. The search unit searches for the keyword received by the keyword reception unit in the text information and the conversion candidate word and extracts a word matching the keyword from words within the text information and the conversion candidate word. The reading unit reads the object information associated with the time point information corresponding to the word matching the keyword from the recording medium. The display unit displays the text information read by the reading unit. 
     According to a third aspect of the present invention, in the second aspect, the recording unit may record the object information, the sound information, the text information, the conversion candidate word, and the time point information on the recording medium such that the object information, the sound information, the text information, the conversion candidate word, and the time point information are associated with each other. The time point information indicates a time point at which the object information was acquired, a time point at which the sound information was acquired, and a time point at which the sound information that is a source of the text information was acquired. The information recording system may further include an event detection unit configured to detect at least two events on the basis of at least one piece of the object information and the sound information recorded on the recording medium. The events are a state in which the at least one piece of the object information and the sound information recorded on the recording medium satisfies a predetermined condition. The reading unit may read at least two pieces of the object information, each of which is associated with the time point information corresponding to an event occurrence time point that is a time point at which the event occurred from the recording medium. The display unit may display the object information read by the reading unit. The search unit may search for the keyword received by the keyword reception unit in the text information and the conversion candidate word that are associated with the time point information corresponding to the event occurrence time point. The display unit may display the object information associated with the time point information corresponding to the event occurrence time point at which the word matching the keyword was detected such that the object information is distinguished from other object information. 
     According to a fourth aspect of the present invention, in the second aspect, the recording unit may record the object information, the sound information, the text information, the conversion candidate word, and the time point information on the recording medium such that the object information, the sound information, the text information, the conversion candidate word, and the time point information are associated with each other. The time point information indicates a time point at which the object information was acquired, a time point at which the sound information was acquired, and a time point at which the sound information that is a source of the text information was acquired. The information recording system may further include an event detection unit configured to detect at least two events on the basis of at least one piece of the object information and the sound information recorded on the recording medium. The events are a state in which the at least one piece of the object information and the sound information recorded on the recording medium satisfies a predetermined condition. The reading unit may read the object information and the text information that are associated with the time point information corresponding to an event occurrence time point that is a time point at which the event occurred from the recording medium. The display unit may display the object information and the text information read by the reading unit. The search unit may search for the keyword received by the keyword reception unit in the text information and the conversion candidate word that are associated with the time point information corresponding to the event occurrence time point. The display unit may display the word that is within the text information and matches the keyword such that the word is distinguished from other words within the text information, and display the word that is within the text information and is associated with the conversion candidate word matching the keyword such that the word is distinguished from other words within the text information. 
     According to a fifth aspect of the present invention, in the third aspect, when a state of the object indicated by the object information is a state predefined as an event detection condition, the event detection unit may detect the event. 
     According to a sixth aspect of the present invention, in the fourth aspect, when a state of the object indicated by the object information is a state predefined as an event detection condition, the event detection unit may detect the event. 
     According to a seventh aspect of the present invention, in the third aspect, the sound information may be a time-series sound signal. When amplitude or power of the sound signal may exceed a threshold value predefined as an event detection condition, the event detection unit may detect the event. 
     According to an eighth aspect of the present invention, in the fourth aspect, the sound information may be a time-series sound signal. When amplitude or power of the sound signal may exceed a threshold value predefined as an event detection condition, the event detection unit may detect the event. 
     According to a ninth aspect of the present invention, in the third aspect, when a sound indicated by the sound information matches a sound of a keyword predefined as an event detection condition, the event detection unit may detect the event. 
     According to a tenth aspect of the present invention, in the fourth aspect, when a sound indicated by the sound information matches a sound of a keyword predefined as an event detection condition, the event detection unit may detect the event. 
     According to an eleventh aspect of the present invention, in the second aspect, the reading unit may read the object information and the text information that are associated with the time point information corresponding to the word matching the keyword from the recording medium. The display unit may display the object information and the text information read by the reading unit. The display unit may display the word that is within the text information and matches the keyword such that the word is distinguished from other words within the text information and display the word that is within the text information and is associated with the conversion candidate word matching the keyword such that the word is distinguished from other words within the text information. 
     According to a twelfth aspect of the present invention, in the second aspect, the recording unit may record the object information, the sound information, and the time point information on the recording medium such that the object information, the sound information, and the time point information are associated with each other. The time point information indicates a time point at which the object information was acquired and a time point at which the sound information was acquired. The reading unit may read the sound information from the recording medium. The sound processing unit may convert the sound information read by the reading unit into the text information and generates the conversion candidate word. The recording unit may associate the text information and the conversion candidate word with the object information and the time point information recorded on the recording medium and record the text information and the conversion candidate word on the recording medium. The time point information with which the text information is associated indicates a time point at which the sound information that is a source of the text information was acquired. 
     According to a thirteenth aspect of the present invention, an information recording method includes a sound acquisition step, a sound processing step, a recording step, a keyword reception step, a search step, a reading step, and a display step. In the sound acquisition step, a sound acquisition unit acquires sound information based on a sound uttered by a user. In the sound processing step, a sound processing unit converts the sound information acquired by the sound acquisition unit into text information and generates at least one conversion candidate word corresponding to the sound in a process of converting the sound information into the text information. In the recording step, a recording unit records the text information and the conversion candidate word on a recording medium such that the text information and the conversion candidate word are associated with each other. In the keyword reception step, a keyword reception unit receives a keyword. In the search step, a search unit searches for the keyword received by the keyword reception unit in the text information and the conversion candidate word and extracts a word matching the keyword from words within the text information and the conversion candidate word. In the reading step, a reading unit reads the text information including a first part corresponding to the word matching the keyword and a second part other than the first part from the recording medium. In the display step, a display unit displays the text information read by the reading unit such that the first part and the second part are able to be distinguished. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram showing a configuration of an information recording system according to a first embodiment of the present invention. 
         FIG. 2  is a flowchart showing a procedure of processing of the information recording system according to the first embodiment of the present invention. 
         FIG. 3  is a diagram showing a schematic configuration of a microscope system according to the first embodiment of the present invention. 
         FIG. 4  is a reference diagram showing a search method of a search unit in the information recording system according to the first embodiment of the present invention. 
         FIG. 5  is a reference diagram showing a screen of a display unit in the information recording system according to the first embodiment of the present invention. 
         FIG. 6  is a reference diagram showing a relationship between an event occurrence time point and an event period in the information recording system according to the first embodiment of the present invention. 
         FIG. 7  is a block diagram showing a configuration of an information recording system according to a first modified example of the first embodiment of the present invention. 
         FIG. 8  is a block diagram showing a configuration of an information recording system according to a second modified example of the first embodiment of the present invention. 
         FIG. 9  is a block diagram showing a configuration of an information recording system according to a third modified example of the first embodiment of the present invention. 
         FIG. 10  is a flowchart showing a procedure of processing of the information recording system according to the third modified example of the first embodiment of the present invention. 
         FIG. 11  is a reference diagram showing event detection based on object information in the information recording system according to the third modified example of the first embodiment of the present invention. 
         FIG. 12  is a reference diagram showing event detection based on object information in the information recording system according to the third modified example of the first embodiment of the present invention. 
         FIG. 13  is a reference diagram showing event detection based on sound information in the information recording system according to the third modified example of the first embodiment of the present invention. 
         FIG. 14  is a reference diagram showing event detection based on sound information in the information recording system according to the third modified example of the first embodiment of the present invention. 
         FIG. 15  is a reference diagram showing a screen of a display unit in the information recording system according to the third modified example of the first embodiment of the present invention. 
         FIG. 16  is a block diagram showing a configuration of an information recording system according to a second embodiment of the present invention. 
         FIG. 17  is a block diagram showing a configuration of an information recording device according to the second embodiment of the present invention. 
         FIG. 18  is a flowchart showing a procedure of processing of the information recording device according to the second embodiment of the present invention. 
         FIG. 19  is a block diagram showing a configuration of an information recording system according to a third embodiment of the present invention. 
         FIG. 20  is a flowchart showing a procedure of processing of the information recording system according to the third embodiment of the present invention. 
         FIG. 21  is a reference diagram showing generation of determined words and conversion candidate words by a sound processing unit and a situation of a search by a search unit in the information recording system according to the third embodiment of the present invention. 
         FIG. 22  is a reference diagram showing text information displayed by a display unit in the information recording system according to the third embodiment of the present invention. 
         FIG. 23  is a block diagram showing a configuration of an information recording system according to a fourth embodiment of the present invention. 
         FIG. 24  is a flowchart showing a procedure of processing of an information recording device according to the fourth embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of the present invention will be described with reference to the drawings. 
     First Embodiment 
       FIG. 1  shows a configuration of an information recording system  10  according to a first embodiment of the present invention. As shown in  FIG. 1 , the information recording system  10  includes an object information acquisition unit  20 , an image acquisition unit  30 , a sound acquisition unit  40 , a sound processing unit  50 , a keyword reception unit  55 , a recording unit  60 , a search unit  65 , a recording medium  70 , a reading unit  80 , a display unit  90 , and a sound output unit  100 . 
     The object information acquisition unit  20  acquires object information about an object. The object is an object to be observed. The observation is an act of figuring out a state of the object. The observation may include acts such as diagnosis, an examination, and an inspection. The object information acquired for observation may not be necessarily visual information of the outside or inside of the object, i.e., image information. For example, the object information acquisition unit  20  is a camera mounted on image devices such as a microscope, an endoscope, a thermal imaging device, an X-ray device, and a computed tomography (CT) device. These image devices acquire image information of the object. These image devices may include a camera that generates image information on the basis of a signal obtained from a sensor. The image information acquired by these image devices may be any one of moving-image information and still-image information. The object information acquisition unit  20  may be a sensor that acquires information such as a temperature, acceleration, pressure, a voltage, and a current of the object. When the object is a living thing, the object information acquisition unit  20  may be a vital sensor that acquires vital information of the object. For example, the vital information is information such as a body temperature, blood pressure, a pulse, an electrocardiogram, or a degree of blood oxygen saturation. The object information acquisition unit  20  may be a microphone that acquires sound information based on a sound uttered by the object. For example, the sound information is information of a hammering test sound, an echo sound, a heart sound, noise, and the like. Additional information such as time point information may be added to the object information acquired by the object information acquisition unit  20 . For example, the object information acquisition unit  20  adds time point information indicating a time point at which the object information was acquired to the object information, and outputs the object information to which the time point information is added. When the object information is time-series information, time point information for identifying a plurality of different time points is added to the object information. For example, the time point information associated with the object information includes a time point at which acquisition of the object information was started and a sampling rate. 
     The image acquisition unit  30  acquires image information indicating a type of situation in which the object information was acquired. The image information acquired by the image acquisition unit  30  indicates a state of at least one of the object and surroundings of the object when the object information is acquired. That is, the image information acquired by the image acquisition unit  30  indicates an observation situation. The image acquisition unit  30  is an image device including a camera. The image acquisition unit  30  acquires the image information in parallel with the acquisition of the object information by the object information acquisition unit  20 . The image information acquired by the image acquisition unit  30  may be any one of moving image-information and still-image information. For example, the image acquisition unit  30  acquires the image information including an image of the at least one of the object and the surroundings of the object. For example, the surroundings of the object include a device on which the object information acquisition unit  20  is mounted. In this case, image information including an image of at least one of the object and the device on which the object information acquisition unit  20  is mounted is acquired. The surroundings of the object may also include an observer who observes the object. In this case, image information including an image of at least one of the object and the observer is acquired. The image acquisition unit  30  is disposed such that at least one of the object and the surroundings of the object is included in a photographing range. 
     When the image information acquired by the image acquisition unit  30  includes an image of the object, the image information includes an image of a part or all of the object. When the image information acquired by the image acquisition unit  30  includes an image of the device on which the object information acquisition unit  20  is mounted, the image information includes an image of a part or all of the device. When the image information acquired by the image acquisition unit  30  includes an image of a user, the image information includes an image of a part or all of the user. When the object information acquisition unit  20  is an image device and the object information is an image of the object, a photographic visual field of the image acquisition unit  30  is wider than that of the object information acquisition unit  20 . For example, the object information acquisition unit  20  acquires image information of a part of the object and the image acquisition unit  30  acquires image information of all of the object. The image acquisition unit  30  may be a wearable camera worn by the user, i.e., an observer. For example, the wearable camera is a head mount type camera mounted in the vicinity of the eyes of the observer such that image information corresponding to the viewpoint of the observer can be acquired. Therefore, the image acquisition unit  30  may be disposed at a position of the viewpoint of the observer who observes the object or in the vicinity of the viewpoint. Additional information such as time point information may be added to the image information acquired by the image acquisition unit  30 . For example, the image acquisition unit  30  adds the time point information indicating a time point at which the image information was acquired to the image information and outputs the image information to which the time point information is added. When the image information is time-series information, time point information for identifying a plurality of different time points is added to the image information. For example, the time point information associated with the image information includes a time point at which acquisition of the image information was started and a sampling rate. 
     The sound acquisition unit  40  acquires sound information based on a sound uttered by the observer who observes the object. For example, the sound acquisition unit  40  is a microphone. The sound acquisition unit  40  may be a wearable microphone worn by the observer. The wearable microphone is worn in the vicinity of the observer&#39;s mouth. The sound acquisition unit  40  may be a microphone having directivity such that only the sound of the observer is acquired. In this case, the sound acquisition unit  40  may not be installed in the vicinity of the observer&#39;s mouth. Thereby, a degree of freedom with respect to the disposition of the sound acquisition unit  40  is obtained. Because noise other than the sound of the observer is eliminated, the efficiency in generation and search of text information is improved. In parallel with the acquisition of the object information by the object information acquisition unit  20 , the sound acquisition unit  40  acquires sound information. Additional information such as time point information may be added to the sound information acquired by the sound acquisition unit  40 . For example, the sound acquisition unit  40  adds the time point information indicating a time point at which the sound information was acquired to the sound information and outputs the sound information to which the time point information is added. When the sound information is time-series information, the time point information for identifying a plurality of different time points is added to the sound information. For example, the time point information associated with the sound information includes a time point at which acquisition of the sound information was started and a sampling rate. 
     The sound processing unit  50  converts the sound information acquired by the sound acquisition unit  40  into text information and generates at least one conversion candidate word corresponding to the sound in a process of converting the sound information into the text information. For example, the sound processing unit  50  includes a sound processing circuit that performs sound processing. The sound processing unit  50  includes a sound recognition unit  500  and a text generation unit  510 . The sound recognition unit  500  recognizes the sound of the user, i.e., the observer, on the basis of the sound information acquired by the sound acquisition unit  40 . The text generation unit  510  generates text information corresponding to the user&#39;s sound by converting the sound recognized by the sound recognition unit  500  into the text information. The text generation unit  510  may divide consecutive sounds into appropriate blocks and generate text information for each block. For example, a block constitutes one sentence or clause. The block may include a part satisfying a predetermined condition. For example, the block may include an utterance part corresponding to a sound “ah”, a silence part, or the like. The block may correspond to an event to be described below. Also, the text generation unit  510  generates at least one conversion candidate word corresponding to the sound in the process of converting the sound information into the text information. For example, the text generation unit  510  extracts candidate words recognized by the sound recognition unit  500  with predetermined accuracy or more. The text generation unit  510  selects a word with the highest accuracy among the candidate words as a determined word. The text generation unit  510  generates text information including the determined word. Also, the text generation unit  510  generates a word other than the determined word among the candidate words as a conversion candidate word. Pronunciation of a conversion candidate word is similar to pronunciation of a determined word. The generated conversion candidate word is associated with the determined word constituting the text information. The sound processing unit  50  (the text generation unit  510 ) outputs the text information and the conversion candidate word. Additional information such as time point information may be added to the text information generated by the sound processing unit  50 . For example, the sound processing unit  50  (the text generation unit  510 ) adds time point information indicating a time point at which the text information was generated to the text information and outputs the text information to which the time point information is added. At this time, the sound processing unit  50  (the text generation unit  510 ) adds the time point information to the determined word. Alternatively, the sound processing unit  50  (the text generation unit  510 ) adds the time point information to the conversion candidate word and the determined word. That is, the sound processing unit  50  (the text generation unit  510 ) adds the time point information to the text information for each word. The time point information may be added to the text information for each block or for each event to be described below. When the text information is time-series information, time point information corresponding to a plurality of different time points is added to the text information. The time point of the text information corresponds to a start time point of the sound information associated with the text information. 
     The object information acquired by the object information acquisition unit  20 , the image information acquired by the image acquisition unit  30 , the sound information acquired by the sound acquisition unit  40 , the text information generated by the sound processing unit  50 , and the conversion candidate word generated by the sound processing unit  50  are input to the recording unit  60 . The recording unit  60  records the object information, the image information, the sound information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the image information, the sound information, the text information, the conversion candidate word, and the time point information are associated with each other. At this time, the recording unit  60  associates the object information, the image information, the sound information, the text information, and the conversion candidate word with each other on the basis of the time point information. For example, the recording unit  60  includes a recording processing circuit that performs an information recording process. At least one piece of the object information, the image information, the sound information, the text information, and the conversion candidate word may be compressed. Therefore, the recording unit  60  may include a compression processing circuit for compressing information. The recording unit  60  may include a buffer for the recording process and the compression process. The time point information indicates time points at which the object information, the image information, and the sound information were acquired. The time point information associated with the text information indicates the time point at which the sound information that is a source of the text information was acquired. For example, the time point information is added to each piece of the object information, the image information, the sound information, and the text information. The object information, the image information, the sound information, and the text information are associated with each other via the time point information. The determined word and the conversion candidate word that constitute the text information are associated with each other. The time point information may be added to the conversion candidate word. In this case, the object information, the image information, the sound information, the text information, and the conversion candidate word are associated with each other via the time point information. 
     The object information, the image information, the sound information, the text information, and the conversion candidate word are associated with each other as information about a common object. The object information, the image information, the sound information, the text information, and the conversion candidate word may be associated with each other as information about a plurality of objects related to each other. For example, each piece of the object information, the image information, the sound information, the text information, and the conversion candidate word includes one file and the recording unit  60  records each file on the recording medium  70 . In this case, information for associating files of the object information, the image information, the sound information, the text information, and the conversion candidate word is recorded on the recording medium  70 . 
     The recording medium  70  is a nonvolatile storage device. For example, the recording medium  70  is at least one of an erasable programmable read only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory, and a hard disk drive. The recording medium  70  may not be disposed at an observation site. For example, the information recording system  10  may have a network interface and the information recording system  10  may be connected to the recording medium  70  via a network such as the Internet or a local area network (LAN). The information recording system  10  may have a wireless communication interface and the information recording system  10  may be connected to the recording medium  70  through wireless communication according to a standard such as Wi-Fi (registered trademark) or Bluetooth (registered trademark). Therefore, the information recording system  10  may not directly include the recording medium  70 . 
     The keyword reception unit  55  receives a keyword. For example, the keyword reception unit  55  is configured as an operation unit. For example, the operation unit is configured to include at least one of a button, a switch, a key, a mouse, a joystick, a touch pad, a track ball, and a touch panel. The keyword reception unit  55  may be configured as a communication unit that wirelessly communicates with the operation unit. The user inputs a keyword for a search via the keyword reception unit  55 . A keyword includes one or more words. 
     The search unit  65  searches for a keyword received by the keyword reception unit  55  in the text information and the conversion candidate word and extracts a word matching the keyword from the word (the determined word) within the text information and the conversion candidate word. For example, the search unit  65  includes an information processing circuit that performs information processing. For example, the text information and the conversion candidate word recorded on the recording medium  70  are read by the reading unit  80 . The search unit  65  searches for the keyword in the text information and the conversion candidate word read by the reading unit  80 . As a result of the search, any one of the determined word and the conversion candidate word can match the keyword. Alternatively, neither the determined word nor the conversion candidate word may match the keyword. Also, the time point information recorded on the recording medium  70  is read by the reading unit  80 . When the determined word matches the keyword, the search unit  65  identifies the time point information associated with the determined word. Thereby, the search unit  65  identifies an utterance time point that is a time point at which a sound corresponding to the keyword was uttered. When the conversion candidate word matches the keyword, the search unit  65  identifies the conversion candidate word or the time point information associated with the determined word corresponding thereto. When the time point information is associated with text information for each block, the search unit  65  identifies the time point information associated with the block. When the time point information is associated with the text information for each event to be described below, the search unit  65  identifies the time point information associated with the event. The recording unit  60  may record the utterance time point identified by the search unit  65  on the recording medium  70 . 
     The reading unit  80  reads the object information, the image information, the sound information, and the text information from the recording medium  70 . Thereby, the reading unit  80  reproduces the object information, the image information, the sound information, and the text information recorded on the recording medium  70 . For example, the reading unit  80  includes a reading processing circuit that performs an information reading process. At least one piece of the object information, the image information, the sound information, and the text information recorded on the recording medium  70  may be compressed. Therefore, the reading unit  80  may include a decompression processing circuit for decompressing the compressed information. The reading unit  80  may include a buffer for a reading process and a decompression process. The reading unit  80  reads the object information, the image information, the sound information, and the text information associated with the time point information corresponding to a word matching a keyword. For example, the reading unit  80  reads the object information, the image information, the sound information, and the text information associated with the same time point information corresponding to the utterance time point identified by the search unit  65 , from the recording medium  70 . When pieces of time point information associated with the information are not synchronized with each other, the reading unit  80  may read the information in consideration of a difference in the time point information with respect to a reference time point. 
     The display unit  90  displays the object information, the image information, and the text information read by the reading unit  80  such that the object information, the image information, and the text information are associated with each other. The display unit  90  is a display device such as a liquid crystal display. For example, the display unit  90  is a monitor of a personal computer (PC). The display unit  90  may be a wearable display such as smart glasses worn by the user. The display unit  90  may be a display unit of a device on which the object information acquisition unit  20  is mounted. The display unit  90  may be a large-size monitor for sharing information. The display unit  90  may be a touch panel display. For example, the display unit  90  simultaneously displays the object information, the image information, and the text information. At this time, the display unit  90  displays the object information, the image information, and the text information in a state in which these pieces of information are arranged. Information selected from a series of object information, image information, and text information corresponding to the same block or the event to be described below and associated with each other may be arranged and displayed on the display unit  90 . Also, the user may be able to switch the information displayed on the display unit  90 . For example, the object information acquired by the sensor or the vital sensor includes time-series sensor signals. For example, the display unit  90  displays a waveform of a sensor signal as a graph. 
     The display unit  90  may visually display the sound information read by the reading unit  80  as character information or a chart. In this case, the display unit  90  displays the object information, the image information, the sound information, and the text information read by the reading unit  80  such that the object information, the image information, the sound information, and the text information are associated with each other. For example, the sound information includes time-series sound signals. For example, the display unit  90  displays a change in amplitude or power of the sound signal over time as a graph. 
     The sound output unit  100  outputs a sound based on the sound information read by the reading unit  80 . For example, the sound output unit  100  is a speaker. 
     When the object information acquired by the object information acquisition unit  20  is image information, the object information may be output to the display unit  90 . The display unit  90  may display the object information in parallel with the acquisition of the object information by the object information acquisition unit  20 . The image information acquired by the image acquisition unit  30  may be output to the display unit  90 . The display unit  90  may display the image information acquired by the image acquisition unit  30  in parallel with the acquisition of the object information by the object information acquisition unit  20 . Thereby, the user can figure out a state of the object and an observation situation in real time. 
     The sound processing unit  50 , the recording unit  60 , the search unit  65 , and the reading unit  80  may include one or more processors. For example, the processor is at least one of a central processing unit (CPU), a digital signal processor (DSP), and a graphics processing unit (GPU). The sound processing unit  50 , the recording unit  60 , the search unit  65 , and the reading unit  80  may include an application specific integrated circuit (ASIC) or a field-programmable gate array (FPGA). 
     In the information recording system  10 , the image information acquisition and recording are optional. Therefore, the information recording system  10  may not include the image acquisition unit  30 . In this case, the recording unit  60  records the object information, the sound information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the sound information, the text information, the conversion candidate word, and the time point information are associated with each other. The time point information indicates time points at which the object information and the sound information were acquired and also indicates a time point at which the sound information that is a source of the text information was acquired. The reading unit  80  reads the object information, the sound information, and the text information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . The display unit  90  displays the object information and the text information read by the reading unit  80  such that the object information and the text information are associated with each other. The sound output unit  100  outputs a sound based on the sound information read by the reading unit  80 . 
     The information recording system  10  may not include the sound output unit  100  and the recording unit  60  may not record the sound information. In this case, the recording unit  60  records the object information, the image information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the image information, the text information, the conversion candidate word, and the time point information are associated with each other. The time point information indicates time points at which the object information and the image information were acquired and also indicates a time point at which the sound information that is a source of the text information was acquired. The reading unit  80  reads the object information, the image information, and the text information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . The display unit  90  displays the object information, the image information, and the text information read by the reading unit  80  such that the object information, the image information, and the text information are associated with each other. 
       FIG. 2  shows a procedure of processing of the information recording system  10 . The procedure of processing of the information recording system  10  will be described with reference to  FIG. 2 . 
     The object information acquisition unit  20  acquires object information about an object (step S 100  (an object information acquisition step)). The object information acquired in step S 100  is stored in the buffer within the recording unit  60 . In parallel with the acquisition of the object information by the object information acquisition unit  20 , the image acquisition unit  30  acquires image information indicating a type of situation in which the object information was acquired (step S 105  (an image acquisition step)). The image information acquired in step S 105  is stored in the buffer within the recording unit  60 . In parallel with the acquisition of the object information by the object information acquisition unit  20 , the processing in step S 110  is performed. Step S 110  includes step S 111  (a sound acquisition step) and step S 112  (a sound processing step). In step S 111 , the sound acquisition unit  40  acquires sound information based on a sound uttered by the observer who observes the object. In step S 112 , the sound processing unit  50  converts the sound information acquired by the sound acquisition unit  40  into text information and generates at least one conversion candidate word corresponding to a sound in a process of converting the sound information into the text information. In step S 110 , the processing in step S 111  and step S 112  is iterated. The sound information acquired in step S 111 , the text information generated in step S 112 , and the conversion candidate word generated in step S 112  are stored in the buffer within the recording unit  60 . Also, the time point information corresponding to the time point at which the information was generated is stored in the buffer within the recording unit  60 . 
     Processing start timings of step S 100 , step S 105 , and step S 110  may not be the same. Processing end timings of step S 100 , step S 105 , and step S 110  may not be the same. At least some of periods during which the processing in step S 100 , step S 105 , and step S 110  is performed overlap each other. 
     After the acquisition of the object information, the image information, and the sound information is completed, the recording unit  60  records the object information, the image information, the sound information, the text information, the conversion candidate word, and the time point information stored in the buffer within the recording unit  60  on the recording medium  70  such that the object information, the image information, the sound information, the text information, the conversion candidate word, and the time point information are associated with each other (step S 115  (a recording step)). 
     After step S 115 , the keyword reception unit  55  receives a keyword (step S 120  (a keyword reception step)). 
     After step S 120 , the search unit  65  searches for the keyword received by the keyword reception unit  55  in the text information and the conversion candidate word, and extracts a word matching the keyword from the words within the text information and the conversion candidate word (step S 125  (a search step)). 
     After step S 125 , the reading unit  80  reads the object information, the image information, the sound information, and the text information associated with the time point information corresponding to the word matching the keyword from the recording medium  70  (step S 130  (a reading step)). The user may be able to specify a timing at which the information is read. 
     After step S 130 , the display unit  90  displays the object information, the image information, and the text information read by the reading unit  80  such that the object information, the image information, and the text information are associated with each other. Also, the sound output unit  100  outputs a sound based on the sound information read by the reading unit  80  (step S 135  (a display step and a sound output step)). 
     When the information recording system  10  does not include the image acquisition unit  30 , the processing in step S 105  is not performed. Also, in step S 115 , the recording unit  60  records the object information, the sound information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the sound information, the text information, the conversion candidate word, and the time point information are associated with each other. In step S 130 , the reading unit  80  reads the object information, the sound information, and the text information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . In step S 135 , the display unit  90  displays the object information and the text information read by the reading unit  80  in step S 130  such that the object information and the text information are associated with each other. Also, in step S 135 , the sound output unit  100  outputs a sound based on the sound information read by the reading unit  80  in step S 130 . 
     When the information recording system  10  does not include the sound output unit  100  and the recording unit  60  does not record the sound information, the recording unit  60  records the object information, the image information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the image information, the text information, the conversion candidate word, and the time point information are associated with each other in step S 115 . In step S 130 , the reading unit  80  reads the object information, the image information, and the text information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . In step S 135 , the display unit  90  displays the object information, the image information, and the text information read by the reading unit  80  in step S 130  such that the object information, the image information, and the text information are associated with each other. 
     At a conventional observation site, the user records a situation of an observation site by writing by hand. On the other hand, because users are working in various environments and situations at a site, there is a case in which it is difficult to record at a site. There are cases in which the users cannot use their hands for reasons of safety or hygiene. In these cases, there is a possibility that a user will cause omissions in recording or erroneous recording due to recording an on-site situation on the basis of ambiguous memory after observation. 
     As described above, the object information is acquired by the object information acquisition unit  20  and the image acquisition unit  30  acquires the image information indicating a type of situation in which the object information was acquired. The acquired object information and image information are recorded on the recording medium  70  by the recording unit  60 . Thereby, the information recording system  10  can record visual information indicating a type of situation in which the object information was acquired. 
     In the above-described method, a burden on the user for recording the information indicating a type of situation in which the object information was acquired is small. Even when the user cannot use his/her hand, necessary information can be recorded and omissions in recording or erroneous recording are reduced. Therefore, the information recording system  10  can accurately and efficiently leave a record showing the type of situation in which the object information was acquired. 
     In the above-described method, the user&#39;s comments when the object information was acquired are recorded as a sound and text corresponding to the sound is recorded in association with the object information and the image information. A “tag” based on the text is attached to the object information, the image information, and the sound information and therefore the user can easily understand a situation when the information was acquired. 
     In the above-described method, the conversion candidate word generated in the process of converting the sound information into the text information is recorded on the recording medium  70  by the recording unit  60 . The search unit  65  searches for the keyword received by the keyword reception unit  55  in the text information and the conversion candidate word and extracts a word matching the keyword from the words within the text information and the conversion candidate word. Even when a word erroneously recognized in a sound recognition process cannot be extracted from the text information through a search, the search unit  65  can extract the conversion candidate word corresponding to the erroneously recognized word. Therefore, the information recording system  10  can reduce omissions in a word search in text information. As a result, the information recording system  10  can provide the user with object information, image information, sound information, and text information corresponding to the keyword received by the keyword reception unit  55 . 
     A specific example of the information recording system  10  will be described below.  FIG. 3  shows a schematic configuration of a microscope system  11  which is an example of the information recording system  10 . As shown in  FIG. 3 , the microscope system  11  includes a microscope  200 , a camera  31   a , a camera  31   b , a camera  31   c , a microphone  41 , a server  201 , and a PC  202 . 
     The microscope  200  is a device for enlarging and observing an object OB 1 . The camera  21  connected to the microscope  200  constitutes the object information acquisition unit  20 . The camera  21  acquires image information of the object OB 1  enlarged by the microscope  200  as object information. For example, the camera  21  acquires moving-image information. 
     The camera  31   a , the camera  31   b , and the camera  31   c  constitute the image acquisition unit  30 . A photographic visual field of each of the camera  31   a , the camera  31   b , and the camera  31   c  is wider than that of the camera connected to the microscope  200 . For example, the camera  31   a , the camera  31   b , and the camera  31   c  acquire moving-image information. 
     The camera  31   a  is disposed in the vicinity of a tip of an objective lens of the microscope  200 . The camera  31   a  acquires image information including an image of the object OB 1  and the tip of the objective lens of the microscope  200  by photographing the vicinity of the tip of the objective lens of the microscope  200 . Thereby, a positional relationship between the object OB 1  and the tip of the objective lens of the microscope  200  is recorded as image information. The user who is the observer does not need to approach the object OB 1  and the tip of the objective lens of the microscope  200  to check states thereof. By viewing the image information acquired by the camera  31   a , the user can easily figure out a situation such as which part of the object OB 1  is being observed or how close the objective lens tip of the microscope  200  is to the object OB 1 . 
     The camera  31   b  is disposed in an indoor space where observation is performed. The camera  31   b  acquires image information including an image of all of the object OB 1  and the microscope  200  by photographing all of the object OB 1  and the microscope  200 . Thereby, all situations of an observation site are recorded as the image information. By viewing the image information acquired by the camera  31   b , the user can easily figure out a situation such as an event occurring in a portion different from a portion to which the user is paying attention. When the object OB 1  is a living thing, the state of the object OB 1  is likely to affect the object information obtained by observation. For example, even when it is difficult to determine a state related to death and life of the object OB 1  from the object information, the user can easily figure out the state of the object OB 1  by viewing the image information acquired by the camera  31   b . The camera  31   b  may acquire image information including an image of the user. 
     The camera  31   c  is configured as a wearable camera. The camera  31   c  is configured as the wearable camera by being attached to an accessory  203  capable of being attached to the user&#39;s head. When the user wears the accessory  203 , the camera  31   c  is disposed at a position near a viewpoint of the user. The camera  31   c  acquires image information including an image of the object OB 1  and the microscope  200  by photographing the object OB 1  and the microscope  200 . Alternatively, the camera  31   c  acquires image information including an image of the microscope  200  without including an image of the object OB 1  by photographing the microscope  200 . Thereby, an observation situation corresponding to a part to which the user is paying attention in observation is recorded as the image information. Thereby, the microscope system  11  can record observation states such as a situation before the object OB 1  is set up on a microscope stage, a procedure of adjusting the microscope  200 , and an adjustment state of the microscope  200 . The user, other people, and the like can easily figure out a situation during the observation in real time or after the end of observation by viewing the recorded observation states. 
     The microphone  41  constitutes the sound acquisition unit  40 . The microphone  41  is configured as a wearable microphone by being attached to the accessory  203 . 
     The server  201  includes the sound processing unit  50 , the keyword reception unit  55 , the recording unit  60 , the search unit  65 , the recording medium  70 , and the reading unit  80 . The object information acquired by the camera  21 , the image information acquired by the camera  31   a , the camera  31   b , and the camera  31   c , and the sound information acquired by the microphone  41  are input to the server  201 . 
     The PC  202  is connected to the server  201 . The screen  91  of the PC  202  constitutes the display unit  90 . The smart glasses may constitute the display unit  90 . In parallel with the acquisition of the object information, the smart glasses may display the image information that is the object information and the image information acquired by each of the camera  31   a , the camera  31   b , and the camera  31   c . By wearing the smart glasses, the user can figure out the state of the object OB 1  and the observation situation in real time. 
     The information recording system  10  may be applied to a microscope system using a multiphoton excitation fluorescence microscope. The multiphoton excitation fluorescence microscope is used within a dark room. A camera connected to the multiphoton excitation fluorescence microscope constitutes the object information acquisition unit  20 . For example, as infrared cameras, the camera  31   a , the camera  31   b , and the camera  31   c  constitute the image acquisition unit  30 . The infrared camera acquires image information including an image of all of the object and the multiphoton excitation fluorescence microscope by photographing all of the object and the multiphoton excitation fluorescence microscope. For example, the user who is an observer wears a wearable microphone constituting the sound acquisition unit  40 . A device such as a PC includes the sound processing unit  50 , the keyword reception unit  55 , the recording unit  60 , the search unit  65 , the recording medium  70 , and the reading unit  80 . The object information acquired by the camera connected to the multiphoton excitation fluorescence microscope, the image information acquired by the infrared camera, and the sound information acquired by the wearable microphone are input to the device. The screen of the device constitutes the display unit  90 . 
     In a dark environment, it is difficult for the user to figure out the state of the microscope and the situation of the experiment and write the state and the situation that have been figured out on paper with the user&#39;s hand. In a system to which the information recording system  10  is applied, the user does not need to stop the experiment and turn on a light in order to know the state of the microscope and the situation of the experiment. Also, the user does not need to temporarily stop the microscope and look into the dark room. Also, the user does not need to manually write the state of the microscope and the situation of the experiment on paper with his/her hand. 
     The information recording system  10  may be applied to an endoscope system. An endoscope is a device for observing the inside of a body of a person, i.e., a patient. The user, i.e., the doctor, utters comments simultaneously with an inspection by the endoscope. The comments uttered by the user can be used to create accurate inspection records. These inspection records are used for the purpose of creating findings, materials for conference presentation, educational content for less experienced doctors, or the like. 
     The information recording system  10  may be applied to a medical examination system at a critical care emergency site. In the examination system, a vital sensor is worn on the person to be examined, i.e., the patient. The vital sensor acquires biological information such as a body temperature, blood pressure, and a pulse of the patient as object information. The user, i.e., the doctor, utters comments simultaneously with the acquisition of the object information by the vital sensor. The comments uttered by the user can be used to accurately and efficiently deliver findings at a site with respect to the patient to other people such as other doctors. 
     The information recording system  10  may be applied to an inspection system. In the inspection system, the probe acquires a signal such as a current according to a defect on the surface of an industrial product such as an aircraft fuselage as the object information. The user utters comments simultaneously with the acquisition of the object information by the probe. The comments uttered by the user can be used to create a work report with respect to examination. The information recording system  10  may be applied to an inspection system using an industrial endoscope. The industrial endoscope acquires image information of objects such as scratches and corrosion inside hollow objects such as boilers, turbines, engines, and chemical plants. 
     The information recording system  10  may be applied to a work recording system. In the work recording system, a camera acquires image information of an object such as a circuit board as the object information. The user utters comments simultaneously with the acquisition of the object information by the camera. The comments uttered by the user can be used to create accurate work records. The work records are used for the purpose of creating a work report related to work with respect to the object and educational content for less experienced workers. Also, the user can easily trace work on the basis of a work history when a problem or the like occurs by storing the work record as the work history. 
     Hereinafter, a search method of the search unit  65  will be described.  FIG. 4  shows the search method of the search unit  65 . In the example shown in  FIG. 4 , a keyword “experiment condition” is specified. The keyword “experiment condition” is pronounced as “jikken jyouken” in Japanese. In the example shown in  FIG. 4 , the keyword “experiment condition” is recognized as the term “ten requirements” without being correctly recognized in the sound recognition process. The term “ten requirements” is pronounced as “jyukken youken” in Japanese. The term “ten requirements” is included in the text information. The keyword “experiment condition” is not included in the text information. Thus, when a search has been performed under the keyword “experiment condition” according to the conventional technology, a part including the term “ten requirements” that is erroneously recognized is not extracted from the text information. That is, omissions in a search occur. 
     The keyword “experiment condition” is divided into two words “experiment” and “condition”. The word “experiment” is pronounced as “jikken” in Japanese. The word “condition” is pronounced as “jyouken” in Japanese. Three conversion candidate words “experiment”, “case”, and “examination” are associated with the word “ten” in the text information which is the determined word after the sound recognition process. These are examples of words that are similar in pronunciation and easily misrecognized. The word “case” is pronounced as “jiken” in Japanese. The word “examination” is pronounced as “jyuken” in Japanese. The word “experiment” included in the keyword matches the word “experiment” in the conversion candidate word. Likewise, three conversion candidate words “securities”, “condition”, and “experiment” whose pronunciations are similar to each other are associated with the word “requirements” in the text information. The word “securities” is pronounced as “syouken” in Japanese. The word “condition” included in the keyword matches the word “condition” in the conversion candidate word. The keyword “experiment condition” does not match the word in the text information. However, the two words constituting the keyword match the conversion candidate words. Therefore, the search unit  65  extracts the term “ten requirements” associated with the conversion candidate words as a corresponding part from the text information. 
     In the above-described example, the search method in Japanese has been described. The above-described method can also be applied to searches in languages other than Japanese. 
     A specific example in which the display unit  90  displays information will be described below.  FIG. 5  shows a screen  92  of the display unit  90 . 
     A keyword input field  300  is displayed on the screen  92 . For example, the user can input a keyword to the keyword input field  300  by operating the operation unit. When the keyword is input to the keyword input field  300 , the keyword reception unit  55  receives the keyword input to the keyword input field  300 . In the example shown in  FIG. 5 , the term “experiment condition” is input as the keyword to the keyword input field  300 . 
     The search unit  65  performs a search on the basis of a keyword received by the keyword reception unit  55 . The search unit  65  extracts a word matching the keyword from words (determined words) within the text information and the conversion candidate word. The search unit  65  identifies an utterance time point by identifying time point information corresponding to the word matching the keyword. The reading unit  80  reads object information, image information, and text information associated with the same time point information corresponding to the utterance time point. The display unit  90  displays the object information, the image information, and the text information read by the reading unit  80  such that the object information, the image information, and the text information are associated with each other. The object information, the image information, and the text information associated with the same object are displayed on the screen  92 . In this example, information in the observation based on the microscope system  11  shown in  FIG. 3  is displayed. 
     In  FIG. 5 , two sets of the object information, the image information, and the text information are displayed. The text information is displayed for each appropriate block such as a sentence or a clause. Here, the corresponding object information, image information, and text information are displayed as the same set on the basis of the time point information associated with the block. The object information, the image information, and the text information corresponding to the same set are arranged in the horizontal direction. The object information, the image information, and the text information of each set are arranged at the same position in the vertical direction. The object information, the image information, and the text information corresponding to the first set are displayed in a region  301  of the screen  92 . The object information, the image information, and the text information corresponding to the second set are displayed in a region  302  of the screen  92 . 
     The object information is an image generated by a camera connected to the microscope  200 . The object information is displayed in a region  303  of the screen  92 . The image information is displayed in a region  304 , a region  305 , and a region  306  of the screen  92 . Image information generated by the camera  31   a  for photographing the vicinity of the tip of the objective lens of the microscope is displayed in the region  304 . Image information generated by the camera  31   b  for photographing all of the object OB 1  and the microscope  200  is displayed in the region  305 . Image information generated by the camera  31   c  attached to the user is displayed in the region  306 . The text information is displayed in a region  307  of the screen  92 . The text information corresponding to the first set includes the term “ten requirements” misrecognized with respect to the keyword “experiment condition”. The text information corresponding to the second set includes text correctly recognized with respect to the keyword “experiment condition”. 
     When the object information recorded on the recording medium  70  is divided into a plurality of pieces in a time series, the reading unit  80  reads the object information associated with the time point information within an event period corresponding to the utterance time point from the recording medium  70 . The display unit  90  displays the object information read by the reading unit  80 . For example, the object information is image information of the object and the image information of the object is moving-image information. The moving-image information includes image information of a plurality of frames generated at different time points. In this case, the reading unit  80  reads image information of the object of the plurality of frames generated during the event period from the recording medium  70 . The display unit  90  sequentially displays the image information of the object of the plurality of frames read by the reading unit  80 . For example, when the user has operated an icon  401 , the display unit  90  displays a moving image of the object during the event period. The event period will be described below. 
     When the object information recorded on the recording medium  70  is divided into a plurality of pieces in a time series, the reading unit  80  may read representative object information associated with the time point information corresponding to the utterance time point from the recording medium  70 . The display unit  90  may display the representative object information read by the reading unit  80 . For example, the object information is image information of the object and the image information of the object is moving-image information. In this case, the reading unit  80  reads the image information of the object of one frame generated at a time point closest to the utterance time point from the recording medium  70 . The display unit  90  displays the image information of the object of one frame read by the reading unit  80 . A thumbnail of one frame generated at a time point closest to the utterance time point may be displayed. 
     When the image information recorded on the recording medium  70  is divided into a plurality of pieces in a time series, the reading unit  80  reads image information associated with the time point information within the event period corresponding to the utterance time point from the recording medium  70 . The display unit  90  displays the image information read by the reading unit  80 . For example, the image information acquired by the image acquisition unit  30  is moving-image information. In this case, the reading unit  80  reads the image information of a plurality of frames generated during the event period from the recording medium  70 . The display unit  90  sequentially displays the image information of the plurality of frames read by the reading unit  80 . For example, when the user has operated any one of an icon  402 , an icon  403 , and an icon  404 , the display unit  90  displays a moving image showing an observation situation during the event period. 
     When the image information recorded on the recording medium  70  is divided into a plurality of pieces in a time series, the reading unit  80  may read representative image information associated with the time point information corresponding to the utterance time point from the recording medium  70 . The display unit  90  may display the representative image information read by the reading unit  80 . For example, the image information acquired by the image acquisition unit  30  is moving-image information. The reading unit  80  reads the image information of one frame generated at a time point closest to the utterance time point from the recording medium  70 . The display unit  90  displays the image information of one frame read by the reading unit  80 . A thumbnail of one frame generated at the time point closest to the utterance time point may be displayed. 
     The reading unit  80  reads the sound information associated with the time point information corresponding to the utterance time point from the recording medium  70 . The sound output unit  100  outputs a sound based on the sound information read by the reading unit  80 . For example, the reading unit  80  reads the sound information associated with the time point information within the event period corresponding to the utterance time point from the recording medium  70 . For example, when the user has operated an icon  405 , the sound output unit  100  outputs the sound during the event period. 
     The display unit  90  may display a word that is within the text information and matches the keyword such that the word is distinguished from other words within the text information and display the word that is within the text information and is associated with the conversion candidate word matching the keyword such that the word is distinguished from other words within the text information. That is, the display unit  90  may display the word that is within the text information and matches the keyword in a first display form, display the word that is within the text information and is associated with the conversion candidate word matching the keyword in a second display form, and display the other words within the text information in a third display form different from the first and second display forms. The first display form and the second display form may be the same. For example, the display unit  90  displays the word that is within the text information and matches the keyword and the word that is within the text information and is associated with the conversion candidate word matching the keyword such that each of the displayed words is emphasized more than the other words within the text information. For example, the display unit  90  displays the above-described words in a color different from those of the other words. The display unit  90  may display the above-described words with characters that are thicker than those of the other words. The display unit  90  may display the above-described words with characters that are larger than those of the other words. A method of distinguishing a specific word from the other words is not limited to the above-described method. By displaying the word corresponding to the keyword in the text information such that the displayed word is distinguished from other words, the user can easily check a search result. 
     Object information, image information, and text information corresponding to the same set may be arranged in the vertical direction. In this case, the object information, the image information, and the text information of each set are arranged at the same position in the horizontal direction. 
     The event period will be described below. The reading unit  80  reads the object information and the image information associated with the time point information corresponding to the time point included in the event period corresponding to the utterance time point from the recording medium  70 . Also, the reading unit  80  reads the sound information and the text information associated with the time point information corresponding to the time point included in the event period corresponding to the utterance time point from the recording medium  70 . 
       FIG. 6  shows a relationship between the event occurrence time point and the event period. An event occurrence time point T 20  is a time point from an event start time ta to an event end time tb. This event continues to occur from the event start time ta to the event end time tb. 
     An event period T 21  is the same as the event occurrence time point T 20 . An event period T 22 , an event period T 23 , and an event period T 24  include a time point before the event occurrence time point T 20 . An end point of the event period T 22  is the event end time point tb. An end point of the event period T 24  is the event start time point ta. An event period T 25 , an event period T 26 , and an event period T 27  include a time point later than the event occurrence time point T 20 . A start point of the event period T 25  is the event start time ta. A start point of the event period T 27  is the event end time tb. An event period T 28  includes only a part of the event occurrence time point. The event period T 28  includes only a time point after the event start time ta and a time point before the event end time tb. 
     In the above description, at least one of a time point before the event occurrence time point and a time point after the event occurrence time point may be a preset predetermined time point. Alternatively, at least one of the time points may be a time point relatively set on the basis of the event occurrence time point corresponding to the event period. Also, at least one of the time points may be set on the basis of the event occurrence time point before or after the event corresponding to the event period. The event may continue to be detected consecutively during a certain period of time. Alternatively, the event may be detected in a trigger manner for a short time. In this case, the event occurrence time point is approximately equal to the event end time point. For example, the event period may be a period from a timing that is 5 seconds before an event in which the amplitude of the sound signal exceeds the threshold value is detected to a timing when an event in which an increase of the object in the image of the object is stopped is detected. 
     The event period is shorter than a period from a first time point to a second time point. The first time point is the earliest time point indicated by the time point information associated with the object information. The second time point is the latest time point indicated by the time point information associated with the object information. When only one event is detected by the event detection unit  75 , the event period may be the same as the period from the first time point to the second time point. The event period related to each piece of the image information, the sound information, and the text information is similar to the event period related to the object information. 
     The utterance time point is a timing at which the user pays attention. As described above, information corresponding to a predetermined period before or after the utterance time point is read from the recording medium  70 . Thus, the user can efficiently view information about an event occurring at a timing when the user pays attention. 
     First Modified Example of First Embodiment 
       FIG. 7  shows a configuration of an information recording system  10   a  according to a first modified example of the first embodiment of the present invention. In terms of the configuration shown in  FIG. 7 , differences from the configuration shown in  FIG. 1  will be described. 
     The information recording system  10   a  includes a situation information acquisition unit  110  in addition to the configuration of the information recording system  10  shown in  FIG. 1 . The situation information acquisition unit  110  acquires situation information that indicates a type of situation in which the object information was acquired and is information other than the image information of the object. For example, the situation information is information about at least one of a time point, a place, and a surrounding environment of the object. For example, the surrounding environment of the object indicates conditions such as temperature, humidity, atmospheric pressure, and illuminance. When the situation information is time point information, the situation information acquisition unit  110  acquires the time point information from a device that generates the time point information. For example, the situation information acquisition unit  110  acquires the time point information from terminals such as a smartphone and a PC. When the situation information is place information, the situation information acquisition unit  110  acquires the place information from a device that generates the place information. For example, the situation information acquisition unit  110  acquires the place information from a terminal such as a smartphone equipped with a Global Positioning System (GPS) function. When the situation information is surrounding environment information, the situation information acquisition unit  110  acquires the surrounding environment information from a device that measures a surrounding environment value. For example, the situation information acquisition unit  110  acquires the surrounding environment information from sensors such as a thermometer, a hygrometer, a barometer, and a luminometer. 
     The situation information may be device information about a device including an object information acquisition unit  20 . The device information may be setting values of the device. For example, in a multiphoton excitation fluorescence microscope, the set values of the device are values such as lens magnification, an amount of observation light, laser power, and a stage position. Additional information such as time point information may be added to the situation information other than the time point information acquired by the situation information acquisition unit  110 . For example, the situation information acquisition unit  110  adds the time point information indicating a time point at which the situation information was acquired to the situation information and outputs the situation information to which the time point information is added. When the situation information is time-series information, time point information for identifying a plurality of different time points is added to the situation information. For example, the time point information associated with the situation information includes a time point at which the acquisition of the situation information was started and a sampling rate. 
     A recording unit  60  records the object information, the image information, the sound information, the text information, the conversion candidate word, the situation information, and the time point information on a recording medium  70  such that the object information, the image information, the sound information, the text information, the conversion candidate word, the situation information, and the time point information are associated with each other. The time point information indicates time points at which the object information, the image information, the sound information, the text information, and the situation information were acquired. The object information, the image information, the sound information, the text information, the conversion candidate word, and the situation information are associated with each other via the time point information. The situation information may be compressed. 
     A reading unit  80  reads the object information, the image information, the text information, and the situation information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . A display unit  90  displays the object information, the image information, the text information, and the situation information read by the reading unit  80  such that the object information, the image information, the text information, and the situation information are associated with each other. For example, the display unit  90  simultaneously displays the object information, the image information, the text information, and the situation information. At this time, the display unit  90  displays the object information, the image information, the text information, and the situation information in a state in which these pieces of information are arranged. Information selected from the object information, the image information, the text information, and the situation information may be displayed on the display unit  90  and the user may be able to switch information to be displayed on the display unit  90 . 
     In terms of points other than the above, the configuration shown in  FIG. 7  is similar to the configuration shown in  FIG. 1 . 
     When the situation information is recorded, the information recording system  10   a  can also record other information as information indicating a type of situation in which the object information was acquired in addition to visual information. Thereby, the information recording system  10   a  can more accurately record an observation situation. Therefore, the user can more accurately reproduce and verify an accurate procedure. 
     Second Modified Example of First Embodiment 
       FIG. 8  shows a configuration of an information recording system  10   b  according to a second modified example of the first embodiment of the present invention. In terms of the configuration shown in  FIG. 8 , differences from the configuration shown in  FIG. 1  will be described. 
     A recording unit  60  records object information, image information, sound information, and time point information on a recording medium  70  such that the object information, the image information, the sound information, and the time point information are associated with each other. A reading unit  80  reads the sound information from the recording medium  70 . A sound processing unit  50  converts the sound information read by a reading unit  80  into text information and generates a conversion candidate word. The recording unit  60  associates the text information and the conversion candidate word with the object information, the image information, the sound information, and the time point information recorded on the recording medium  70  and records the text information and the conversion candidate word on the recording medium  70 . The time point information indicates a time point at which the sound information that is a source of the text information was acquired. 
     In terms of points other than the above, the configuration shown in  FIG. 8  is similar to the configuration shown in  FIG. 1 . 
     In the information recording system  10   b , after the entire sound information is recorded on the recording medium  70 , the sound processing is performed by the sound processing unit  50 . Generally, the load of sound processing is high. Even when the sound processing rate is lower than the acquisition rate of the sound information, the information recording system  10   b  can record text information. 
     Third Modified Example of First Embodiment 
       FIG. 9  shows a configuration of an information recording system  10   c  according to a third modified example of the first embodiment of the present invention. In terms of the configuration shown in  FIG. 9 , differences from the configuration shown in  FIG. 1  will be described. 
     The information recording system  10   c  includes an event detection unit  75  in addition to the configuration of the information recording system  10  shown in  FIG. 1 . The event detection unit  75  detects an event on the basis of at least one piece of the object information, the image information, and the sound information recorded on the recording medium  70 . The event is a state in which the at least one piece of the object information, the image information, and the sound information recorded on the recording medium  70  satisfies a predetermined condition. For example, the event detection unit  75  includes an information processing circuit that performs information processing. When the event detection unit  75  processes the image information, the event detection unit  75  includes an image processing circuit. When the event detection unit  75  processes the sound information, the event detection unit  75  includes a sound processing circuit. For example, the at least one piece of the object information, the image information, and the sound information recorded on the recording medium  70  is read by the reading unit  80 . The event detection unit  75  detects an event on the basis of the information read by the reading unit  80 . Also, the time point information recorded on the recording medium  70  is read by the reading unit  80 . The event detection unit  75  identifies the event occurrence time point which is a time point at which the event occurred on the basis of a relationship between the time point information read by the reading unit  80  and information in which the event was detected. The recording unit  60  may record the event occurrence time point identified by the event detection unit  75  on the recording medium  70 . 
     The reading unit  80  reads the object information, the image information, and the text information associated with the time point information corresponding to the event occurrence time point from the recording medium  70 . The display unit  90  displays the object information, the image information, and the text information read by the reading unit  80 . The search unit  65  searches for a keyword received by a keyword reception unit  55  in the text information and a conversion candidate word associated with the time point information corresponding to the event occurrence time point. The display unit  90  displays the object information, the image information, and the text information associated with the time point information corresponding to the event occurrence time point at which the word matching the keyword was detected such that the object information, the image information, and the text information are distinguished from other object information, other image information, and other text information. That is, the display unit  90  displays the object information, the image information, and the text information associated with the time point information corresponding to the event occurrence time point at which the word matching the keyword was detected in a first display form and displays other object information, other image information, and other text information in a second display form different from the first display form. The display forms are distinguished by changing a color and a thickness of a frame for displaying information, for example, according to a degree of emphasis for display. 
     The time point information is added to a determined word constituting the text information. Alternatively, the time point information is added to the determined word and the conversion candidate word. The event occurrence time point at which the word matching the keyword was detected is a time point indicated by the time point information added to the word. The conversion candidate word is associated with the determined word constituting the text information. When the conversion candidate word to which the time point information is not added matches the keyword, the time point information added to the determined word associated with the conversion candidate word indicates the event occurrence time point at which the conversion candidate word was detected. 
     The time point information may be added to the text information for each event detected by the event detection unit  75 . That is, the event occurrence time point may be added to the text information. 
     When the information recording system  10   c  does not include the image acquisition unit  30 , the recording unit  60  records the object information, the sound information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the sound information, the text information, the conversion candidate word, and the time point information are associated with each other. The event detection unit  75  detects an event on the basis of at least one piece of the object information and the sound information recorded on the recording medium  70 . The reading unit  80  reads the object information, the sound information, and the text information associated with the time point information corresponding to the event occurrence time point from the recording medium  70 . The display unit  90  displays the object information and the text information read by the reading unit  80  such that the object information and the text information are associated with each other. The sound output unit  100  outputs a sound on the basis of the sound information read by the reading unit  80 . The display unit  90  displays the object information and the text information associated with the time point information corresponding to the event occurrence time point at which the word matching the keyword was detected such that the object information and the text information are distinguished from other object information and other text information. 
     The information recording system  10   c  may not include the sound output unit  100  and the recording unit  60  may not record sound information. In this case, the recording unit  60  records the object information, the image information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the image information, the text information, the conversion candidate word, and the time point information are associated with each other. The event detection unit  75  detects an event on the basis of at least one piece of the object information and the image information recorded on the recording medium  70 . The reading unit  80  reads the object information, the image information, and the text information associated with the time point information corresponding to the event occurrence time point from the recording medium  70 . The display unit  90  displays the object information, the image information, and the text information read by the reading unit  80  such that the object information, the image information, and the text information are associated with each other. The display unit  90  displays the object information, the image information, and the text information associated with the time point information corresponding to the event occurrence time point at which the word matching the keyword was detected such that the object information, the image information, and the text information are distinguished from other object information, other image information, and other text information. 
     In terms of points other than the above, the configuration shown in  FIG. 9  is similar to the configuration shown in  FIG. 1 . 
       FIG. 10  shows a procedure of processing of the information recording system  10   c . In terms of the processing shown in  FIG. 10 , differences from the processing shown in  FIG. 2  will be described. 
     After step S 115 , the event detection unit  75  detects an event on the basis of at least one piece of object information, image information, and sound information recorded on the recording medium  70  (step S 140  (an event detection step)). 
     After step S 140 , the reading unit  80  reads the object information, the image information, the sound information, and text information associated with time point information corresponding to an event occurrence time point that is a time point at which an event occurred from the recording medium  70  (step S 145  (a reading step)). The user may be able to specify a timing at which the information is read. 
     After step S 145 , the display unit  90  displays the object information, the image information, and the text information read by the reading unit  80  such that the object information, the image information, and the text information are associated with each other. Also, the sound output unit  100  outputs a sound based on the sound information read by the reading unit  80  (step S 150  (a display step and a sound output step)). After step S 150 , the processing in step S 120  is performed. 
     After step S 125 , the display unit  90  displays the object information, the image information, and the text information associated with the time point information corresponding to the event occurrence time point at which a word matching a keyword was detected such that the object information, the image information, and the text information are distinguished from other object information, other image information, and other text information (step S 155  (a display step)). 
     In terms of points other than the above, the processing shown in  FIG. 10  is similar to the processing shown in  FIG. 2 . 
     When the information recording system  10   c  does not include the image acquisition unit  30 , the processing in step S 105  is not performed. Also, in step S 115 , the recording unit  60  records the object information, the sound information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the sound information, the text information, the conversion candidate word, and the time point information are associated with each other. In step S 140 , the event detection unit  75  detects an event on the basis of at least one piece of the object information and the sound information recorded on the recording medium  70 . In step S 145 , the reading unit  80  reads the object information, the sound information, and the text information associated with the time point information corresponding to the event occurrence time point from the recording medium  70 . In step S 150 , the display unit  90  displays the object information and the text information read by the reading unit  80  such that the object information and the text information are associated with each other. Also, in step S 150 , the sound output unit  100  outputs a sound based on the sound information read by the reading unit  80 . In step S 155 , the display unit  90  displays the object information and the text information associated with the time point information corresponding to the event occurrence time point at which the word matching the keyword was detected such that the object information and the text information are distinguished from other object information and other text information. 
     When the information recording system  10   c  does not include the sound output unit  100  and the recording unit  60  does not record sound information, the recording unit  60  records object information, image information, text information, a conversion candidate word, and time point information on the recording medium  70  such that the object information, the image information, the text information, the conversion candidate word, and the time point information are associated with each other in step S 115 . In step S 140 , the event detection unit  75  detects an event on the basis of at least one piece of the object information and the image information recorded on the recording medium  70 . In step S 145 , the reading unit  80  reads the object information, the image information, and the text information associated with the time point information corresponding to the event occurrence time point from the recording medium  70 . In step S 150 , the display unit  90  displays the object information, the image information, and the text information read by the reading unit  80  such that the object information, the image information, and the text information are associated with each other. In step S 155 , the display unit  90  displays the object information, the image information, and the text information associated with the time point information corresponding to the event occurrence time point at which the word matching the keyword was detected such that the object information, the image information, and the text information are distinguished from other object information, other image information, and other text information. 
     As described above, the event is detected on the basis of at least one piece of the object information, the image information, and the sound information recorded on the recording medium  70 . Information associated with the time point information corresponding to the event occurrence time point at which the word matching the keyword within the information corresponding to the event was detected is displayed such that the information is distinguished from other information. Thereby, the information recording system  10   c  can support efficient information viewing of the user. 
     According to the above-described method, the information recording system  10   c  can extract a useful scene to which the user pays attention and a list of information about the scene from a plurality of pieces of and a large amount of information recorded at an observation site. Also, the information recording system  10   c  can extract information corresponding to a keyword from the list. Therefore, the user can efficiently view information about an event occurring at a timing when the user pays attention. 
     A specific example of event detection of the event detection unit  75  will be described below. 
       FIGS. 11 and 12  show examples of event detection based on the object information. In  FIGS. 11 and 12 , the object information is image information (a microscope image) of the object acquired by the camera connected to the microscope. 
     As shown in  FIG. 11 , an object OB 10  is included in an image G 10 . An image G 11  is captured at a time point later than that when the image G 10  was captured. The object OB 10  is included in the image G 11 . The shape of the object OB 10  is different between the image G 10  and the image G 11 . That is, the shape of the object OB 10  varies with time. When the shape of the object OB 10  has changed, the event detection unit  75  detects an event. For example, the event detection unit  75  determines whether or not an event in which the shape of the object OB 10  changes has occurred by comparing image information of a plurality of frames acquired at different time points. 
     As shown in  FIG. 12 , an object OB 11 , an object OB 12 , an object OB 13 , and an object OB 14  are included in an image G 12 . An image G 13  is captured at a time point later than a time point when the image G 12  was captured. In addition to the objects OB 11  to OB 14 , an object OB 15 , an object OB 16 , and an object OB 17  are included in the image G 13 . The objects OB 15  to OB 17  are added between the image G 12  and the image G 13 . That is, the number of objects varies with time. When the number of objects has changed, the event detection unit  75  detects an event. For example, the event detection unit  75  determines whether or not an event in which the number of objects changes has occurred by comparing image information of a plurality of frames acquired at different time points. 
     When a state of the object indicated by the object information is a state predefined as an event detection condition, the event detection unit  75  detects the event. For example, the event detection condition is recorded on the recording medium  70  in advance. The reading unit  80  reads the event detection condition from the recording medium  70 . The event detection unit  75  detects an event on the basis of the event detection condition read by the reading unit  80 . Thereby, the event detection unit  75  can detect a phenomenon that the object is in a predetermined state as the event. 
     The image acquisition unit  30  acquires image information including an image of at least one of the object and surroundings of the object. When at least one state of the object and the surroundings of the object indicated by the image information is a state predefined as the event detection condition, the event detection unit  75  detects the event. For example, when a feature of the image information is the same as a feature predefined as the event detection condition, the event detection unit  75  detects the event. For example, in a microscope system using a multiphoton excitation fluorescence microscope, the event detection unit  75  detects an event when it is detected that light has entered a dark room from the image information. For example, in the examination system  13 , the event detection unit  75  detects an event when a state such as bleeding or seizure of a patient is detected from image information. For example, feature information indicating the above-described feature is recorded on the recording medium  70  in advance as an event detection condition. The event detection unit  75  extracts the feature information from the image information. The reading unit  80  reads the event detection condition from the recording medium  70 . The event detection unit  75  compares the feature information extracted from the image information with the feature information that is the event detection condition read by the reading unit  80 . When the feature information extracted from the image information is the same as or similar to the feature information as the event detection condition, the event detection unit  75  detects the event. Thereby, the event detection unit  75  can detect a phenomenon that the observation state indicated by the image information becomes a predetermined state as an event. 
       FIGS. 13 and 14  show examples of event detection based on sound information. In  FIGS. 13 and 14 , the sound information is a time-series sound signal (sound data). The sound signal includes amplitude information of the sound at each of the plurality of time points.  FIG. 13  shows a graph of a sound signal A 10  and  FIG. 14  shows a graph of a sound signal A 11 . In the graphs of  FIGS. 13 and 14 , the horizontal direction represents time and the vertical direction represents amplitude. 
     The sound signal A 10  shown in  FIG. 13  is a sound during an inspection with an industrial endoscope. For example, the amplitude of the sound signal exceeds a threshold value during a period T 10 , a period T 11 , and a period T 12  shown in  FIG. 13 . The threshold value is greater than zero. The user is an inspector. For example, during the period T 10 , the user utters a sound indicating that there is a scratch at a position of 250 mm. For example, during the period T 11 , the user utters a sound indicating that there is a hole with a diameter of 5 mm at a position of 320 mm. For example, during the period T 12 , the user utters a sound indicating that there is rust at a position of 470 mm. When the amplitude of the sound signal exceeds the predetermined threshold value, the event detection unit  75  detects the event. Even when the user has uttered a series of sounds, a sound signal at that time includes a period with small amplitude. When a plurality of events are continuously detected within a predetermined time, the event detection unit  75  may aggregate the plurality of events as one event. Alternatively, the event detection unit  75  may use an average value of amplitudes within a predetermined time or the like as a representative value and detect the presence or absence of an event at predetermined time intervals. In this manner, the event detection unit  75  detects the event during the period T 10 , the period T 11 , and the period T 12  corresponding to a period during which the user has uttered the sound. 
     The threshold value may be smaller than zero. If the amplitude of the sound signal is smaller than the threshold value smaller than 0, the amplitude of the sound signal exceeds the threshold value. When the power of the sound signal exceeds a predetermined threshold value, the event detection unit  75  may detect the event. For example, the power of the sound signal is a square mean value of the amplitude. 
     As described above, the sound acquisition unit  40  acquires sound information based on the sound uttered by the observer who observes the object. The sound information is a time-series sound signal. When the amplitude or the power of the sound signal exceeds the threshold value predefined as the event detection condition, the event detection unit  75  detects the event. For example, a threshold value determined on the basis of amplitude or power of predetermined sound information or a threshold value specified by a user who is the observer is recorded on the recording medium  70  in advance as the event detection condition. The reading unit  80  reads the event detection condition from the recording medium  70 . The event detection unit  75  compares the amplitude or power of the sound signal acquired by the sound acquisition unit  40  with the threshold value which is the event detection condition read by the reading unit  80 . When the amplitude or the power of the sound signal exceeds the threshold value, the event detection unit  75  detects the event. Thereby, the event detection unit  75  can detect a phenomenon when the user has uttered comments as the event. 
     The sound signal A 11  shown in  FIG. 14  is a sound during the inspection with a medical endoscope. The user is a doctor. For example, during the period T 13  shown in  FIG. 14 , the user utters a word “polyp”. When the word “polyp” is registered as a keyword for event detection in advance, the event detection unit  75  detects an event during the period T 13 . 
     As described above, the sound acquisition unit  40  acquires sound information based on the sound uttered by the observer who observes the object. When the sound indicated by the sound information is the same as the sound of the keyword predefined as the event detection condition, the event detection unit  75  detects the event. For example, the sound information generated by acquiring the sound of the keyword is recorded on the recording medium  70  in advance as the event detection condition. The reading unit  80  reads the event detection condition from the recording medium  70 . The event detection unit  75  compares the sound information acquired by the sound acquisition unit  40  with the sound information that is the event detection condition read by the reading unit  80 . For example, when the two pieces of the sound information are the same, i.e., when the similarity between the two pieces of the sound information is greater than or equal to a predetermined value, the event detection unit  75  detects the event. Thereby, the event detection unit  75  can detect a phenomenon when the user who is the observer utters a predetermined keyword as the event. 
     In the observation site, in many cases, the user recognizes the state of the object or the observation situation and utters comments with respect to the state of the object or the observation situation. Thus, when the event detection unit  75  detects an event on the basis of the sound information, the event detection unit  75  can more easily detect the event to which the user pays attention. 
     A specific example of display of information by the display unit  90  will be described below.  FIG. 15  shows a window W 10  displayed on a screen  93  of the display unit  90 . 
     The event detection unit  75  detects an event on the basis of at least one piece of the object information, the image information, and the sound information recorded on the recording medium  70 . The reading unit  80  reads the object information, the image information, and the text information associated with the time point information corresponding to the event occurrence time point from the recording medium  70 . The display unit  90  displays the object information, the image information, and the text information read by the reading unit  80  such that the object information, the image information, and the text information are associated with each other. 
     The event detection unit  75  detects a plurality of event occurrence time points. The reading unit  80  reads the object information, the image information, and the text information associated with time point information corresponding to each of the plurality of event occurrence time points from the recording medium  70 . The display unit  90  displays the object information, the image information, and the text information read by the reading unit  80  at each event occurrence time point such that the object information, the image information, and the text information are associated with each other. In the present example, information in the observation with the microscope system  11  shown in  FIG. 3  is shown. 
     In  FIG. 15 , object information, image information, and text information corresponding to five events among a plurality of events are shown. Object information, image information, and text information corresponding to the same event are displayed such that the object information, the image information, and the text information are associated with each other. The object information, the image information, and the text information corresponding to the same event are arranged in the horizontal direction. The object information, the image information, and the text information in each event are associated with the same position of the vertical direction. The object information, the image information, and the text information corresponding to an event 1 are displayed in a region  308  of the screen  93 . The object information, the image information, and the text information corresponding to an event 2 are displayed in a region  309  of the screen  93 . The object information, the image information, and the text information corresponding to an event 3 are displayed in a region  310  of the screen  93 . The object information, the image information, and the text information corresponding to an event 4 are displayed in a region  311  of the screen  93 . The object information, the image information, and the text information corresponding to an event 5 are displayed in a region  312  of the screen  93 . 
     The object information is an image generated by a camera connected to the microscope  200 . The object information is displayed in a region  313  of the screen  93 . The image information is displayed in a region  314 , a region  315 , and a region  316  of the screen  93 . Image information generated by the camera  31   a  for photographing the vicinity of the tip of the objective lens of the microscope is displayed in the region  314 . Image information generated by the camera  31   b  for photographing all of the object OB 1  and the microscope  200  is displayed in the region  315 . Image information generated by the camera  31   c  attached to the user is displayed in the region  316 . Text information is displayed in a region  317  of the screen  93 . 
     When the object information recorded on the recording medium  70  is divided into a plurality of pieces in a time series, the reading unit  80  reads object information associated with the time point information within the event period corresponding to the event occurrence time point from the recording medium  70 . The display unit  90  displays the object information read by the reading unit  80 . For example, when the user has operated an icon  401 , the display unit  90  displays a moving image of the object during the event period. The reading unit  80  may read representative object information associated with the time point information corresponding to the event occurrence time point from the recording medium  70 . The display unit  90  may display the representative object information read by the reading unit  80 . For example, the representative object information is image information of an object of one frame generated at a time point closest to the event occurrence time point. The representative object information may be a thumbnail of one frame generated at the time point closest to the event occurrence time point. 
     When the image information recorded on the recording medium  70  is divided into a plurality of pieces in a time-series, the reading unit  80  reads the image information associated with the time point information within the event period corresponding to the event occurrence time point from the recording medium  70 . The display unit  90  displays the image information read by the reading unit  80 . For example, when the user has operated any one of an icon  402 , an icon  403 , and an icon  404 , the display unit  90  displays a moving image showing an observation situation during the event period. The reading unit  80  may read representative image information associated with the time point information corresponding to the event occurrence time point from the recording medium  70 . The display unit  90  may display representative image information read by the reading unit  80 . For example, the representative image information is image information of one frame generated at the time point closest to the event occurrence time point. The representative image information may be a thumbnail of one frame generated at the time point closest to the event occurrence time point. 
     The reading unit  80  reads the sound information associated with the time point information corresponding to the event occurrence time point from the recording medium  70 . The sound output unit  100  outputs a sound based on the sound information read by the reading unit  80 . For example, the reading unit  80  reads the sound information associated with the time point information within the event period corresponding to the event occurrence time point from the recording medium  70 . For example, when the user has operated an icon  405 , the sound output unit  100  outputs a sound during the event period. 
     The description of the event period in the first embodiment can be applied to the description of the event period in the third modified example of the first embodiment. An utterance time point in the above description is replaced with the event occurrence time point. 
     After the information of each event shown in  FIG. 15  is displayed, the user can input a keyword to a keyword input field  300  by operating an operation unit. When the keyword is input to the keyword input field  300 , the keyword reception unit  55  receives the keyword input to the keyword input field  300 . In the example shown in  FIG. 15 , the term “experiment condition” is input as the keyword to the keyword input field  300 . 
     The search unit  65  searches for the keyword received by the keyword reception unit  55  in the text information and the conversion candidate word associated with the time point information within the event period. That is, the search unit  65  searches for the keyword in the text information displayed by the display unit  90  and the conversion candidate word associated with the word within the text information. The search unit  65  extracts the word matching the keyword from the word (the determined word) within the text information and the conversion candidate word. The display unit  90  displays the object information, the image information, and the text information within an event period corresponding to the time point information corresponding to an event occurrence time point at which the word matching the keyword was detected such that the object information, the image information, and the text information are distinguished from other object information, other image information, and other text information. 
     In the example shown in  FIG. 15 , the text information corresponding to the event 1 does not include the keyword “experiment condition”, but includes the term “ten requirements” which is an erroneous recognition result. Also, conversion candidate words associated with the text information corresponding to the event 1 include the keyword “experiment condition”. The text information corresponding to the event 3 includes the keyword “experiment condition”. Thus, the display unit  90  displays the object information, the image information, and the text information corresponding to each of the event 1 and the event 3 such that they are distinguished from the object information, the image information, and the text information corresponding to each of the event 2, the event 4, and the event 5. Specifically, the display unit  90  displays the object information, the image information, and the text information corresponding to each of the event 1 and the event 3 such that they are emphasized more than the object information, the image information, and the text information corresponding to each of the event 2, the event 4, and the event 5. For example, the object information, the image information, and the text information corresponding to each of the event 1 and the event 3 are surrounded by thick lines. 
     The display unit  90  may brightly display the object information, the image information, and the text information corresponding to each of the event 1 and the event 3. The display unit  90  may enlarge and display the object information, the image information, and the text information corresponding to each of the event 1 and the event 3. A method of distinguishing information of an event corresponding to an event occurrence time point at which a word matching a keyword was detected from information of another event is not limited to the above-described method. 
     The display unit  90  may display the word that is within the text information and matches the keyword such that the word is distinguished from other words within the text information and display the word that is within the text information and is associated with the conversion candidate word matching the keyword such that the word is distinguished from other words within the text information. 
     As described above, information associated with the time point information corresponding to the event occurrence time point at which the word matching the keyword within the information corresponding to the event was detected is displayed such that the information is distinguished from other information. Thus, the user can easily recognize information corresponding to a desired keyword. Also, the word corresponding to the keyword in the text information is displayed such that the word is distinguished from other words and therefore the user can easily check a search result. 
     The information recording system  10   c  may include a situation information acquisition unit  110  in the information recording system  10   a  shown in  FIG. 7 . When the situation indicated by situation information is a state predefined as an event detection condition, the event detection unit  75  may detect an event. For example, the situation information is surrounding environment information acquired from a thermometer, i.e., a temperature. When the temperature indicated by the situation information exceeds a threshold value predefined as the event detection condition, the event detection unit  75  detects an event. For example, a threshold value specified by the user is recorded on the recording medium  70  in advance as the event detection condition. The reading unit  80  reads the event detection condition from the recording medium  70 . The event detection unit  75  compares the temperature indicated by the situation information acquired by the situation information acquisition unit  110  with the threshold value that is the event detection condition read by the reading unit  80 . When the temperature exceeds the threshold value, the event detection unit  75  detects an event. 
     Second Embodiment 
       FIG. 16  shows a configuration of an information recording system  10   d  according to a second embodiment of the present invention. In terms of the configuration shown in  FIG. 16 , differences from the configuration shown in  FIG. 1  will be described. 
     As shown in  FIG. 16 , the information recording system  10   d  includes an object information acquisition unit  20 , an image acquisition unit  30 , a sound acquisition unit  40 , an information recording device  120 , a display unit  90 , and a sound output unit  100 . Configurations of the object information acquisition unit  20 , the image acquisition unit  30 , the sound acquisition unit  40 , the display unit  90 , and the sound output unit  100  are similar to those corresponding to the components shown in  FIG. 1 . In the information recording system  10   d  shown in  FIG. 16 , the sound processing unit  50 , the keyword reception unit  55 , the recording unit  60 , the search unit  65 , the recording medium  70 , and the reading unit  80  in the information recording system  10  shown in  FIG. 1  are changed to the information recording device  120 . 
     In terms of points other than the above, the configuration shown in  FIG. 16  is similar to the configuration shown in  FIG. 1 . 
       FIG. 17  shows a configuration of the information recording device  120 . As shown in  FIG. 17 , the information recording device  120  includes a sound processing unit  50 , a keyword reception unit  55 , a recording unit  60 , a search unit  65 , a recording medium  70 , a reading unit  80 , an input unit  130 , and an output unit  140 . 
     The configurations of the sound processing unit  50 , the keyword reception unit  55 , the recording unit  60 , the search unit  65 , the recording medium  70 , and the reading unit  80  are similar to those corresponding to the components shown in  FIG. 1 . Object information from the object information acquisition unit  20 , image information from the image acquisition unit  30 , and sound information from the sound acquisition unit  40  are input to the input unit  130 . For example, at least one of the object information acquisition unit  20 , the image acquisition unit  30 , and the sound acquisition unit  40  is connected to the information recording device  120  through a cable. In this case, the input unit  130  is an input terminal to which the cable is connected. At least one of the object information acquisition unit  20 , the image acquisition unit  30 , and the sound acquisition unit  40  may be wirelessly connected to the information recording device  120 . In this case, the input unit  130  is a wireless communication circuit that wirelessly communicates with at least one of the object information acquisition unit  20 , the image acquisition unit  30 , and the sound acquisition unit  40 . 
     The output unit  140  outputs the object information, the image information, the sound information, and the text information read by the reading unit  80 . That is, the output unit  140  outputs the object information, the image information, and the text information to the display unit  90  and outputs the sound information to the sound output unit  100 . For example, at least one of the display unit  90  and the sound output unit  100  is connected to the information recording device  120  through a cable. In this case, the output unit  140  is an output terminal to which the cable is connected. At least one of the display unit  90  and the sound output unit  100  may be wirelessly connected to the information recording device  120 . In this case, the output unit  140  is a wireless communication circuit that wirelessly communicates with at least one of the display unit  90  and the sound output unit  100 . 
     The information recording device  120  may read a program and execute the read program. That is, the function of the information recording device  120  may be implemented by software. This program includes instructions for defining the operations of the sound processing unit  50 , the recording unit  60 , the search unit  65 , and the reading unit  80 . For example, this program may be provided by a “computer-readable recording medium” such as a flash memory. Also, the above-described program may be transmitted from a computer having a storage device or the like in which the program is stored to the information recording device  120  via a transmission medium or transmission waves in the transmission medium. The “transmission medium” for transmitting the program refers to a medium having an information transmission function, for example, a network (a communication network) such as the Internet or a communication circuit (a communication line) such as a telephone circuit. Also, the above-described program may be a program for implementing some of the above-described functions. Further, the above-described program may be a program capable of implementing the above-described function in combination with a program already recorded on the computer, i.e., a so-called differential file (differential program). 
     Various modifications applied to the information recording system  10  shown in  FIG. 1  may be similarly applied to the information recording system  10   d  shown in  FIG. 16 . For example, the information recording system  10   d  may not include the image acquisition unit  30 . In this case, the object information and the sound information are input to the input unit  130 . The recording unit  60  records the object information, the sound information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the sound information, the text information, the conversion candidate word, and the time point information are associated with each other. The reading unit  80  reads the object information and the text information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . The output unit  140  outputs the object information, the sound information, and the text information read by the reading unit  80 . The display unit  90  displays the object information and the text information output by the output unit  140  such that the object information and the text information are associated with each other. The text information may not be output from the information recording device  120 . The sound output unit  100  outputs a sound based on the sound information output by the output unit  140 . 
     The information recording system  10   d  does not include the sound output unit  100  and the recording unit  60  may not record sound information. In this case, the object information, the image information, and the sound information are input to the input unit  130 . The recording unit  60  records the object information, the image information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the image information, the text information, the conversion candidate word, and the time point information are associated with each other. The reading unit  80  reads the object information, the image information, and the text information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . The output unit  140  outputs the object information, the image information, and the text information read by the reading unit  80 . The display unit  90  displays the object information, the image information, and the text information output by the output unit  140  such that the object information, the image information, and the text information are associated with each other. No text information may be output from the information recording device  120 . 
       FIG. 18  shows a procedure of processing of the information recording device  120 . The procedure of processing of the information recording device  120  will be described with reference to  FIG. 18 . 
     Object information about the object is input to the input unit  130  (step S 200  (an input step)). The object information input in step S 200  is stored in a buffer within the recording unit  60 . In parallel with the input of the object information to the input unit  130 , image information indicating a type of situation in which the object information was acquired is input to the input unit  130  (step S 205  (an input step)). The image information input in step S 205  is stored in the buffer within the recording unit  60 . In parallel with the input of the object information to the input unit  130 , the processing in step S 210  is performed. Step S 210  includes step S 211  (a sound input step) and step S 212  (a sound processing step). In step S 211 , sound information based on a sound uttered by an observer who observes the object is input to the input unit  130 . In step S 212 , the sound processing unit  50  converts the sound information input to the input unit  130  into text information and generates at least one conversion candidate word corresponding to the sound in the process of converting the sound information into the text information. In step S 210 , the processing in steps S 211  and S 212  is iterated. The sound information input in step S 211 , the text information generated in step S 212 , and the conversion candidate word generated in step S 212  are stored in the buffer within the recording unit  60 . 
     Processing start timings of step S 200 , step S 205 , and step S 210  may not be the same. Processing end timings of step S 200 , step S 205 , and step S 210  may not be the same. At least some of periods during which the processing in step S 200 , step S 205 , and step S 210  is performed overlap each other. 
     After the input of the object information, the image information, and the sound information is completed, the recording unit  60  records the object information, the image information, the sound information, the text information, the conversion candidate word, and the time point information stored in the buffer within the recording unit  60  on the recording medium  70  such that the object information, the image information, the sound information, the text information, the conversion candidate word, and the time point information are associated with each other (step S 215  (a recording step)). 
     After step S 215 , the keyword reception unit  55  receives a keyword (step S 220  (a keyword reception step)). 
     After step S 220 , the search unit  65  searches for the keyword received by the keyword reception unit  55  in the text information and the conversion candidate word, and extracts a word matching the keyword from words within the text information and the conversion candidate word (step S 225  (a search step)). 
     After step S 225 , the reading unit  80  reads the object information, the image information, the sound information, and the text information associated with the time point information corresponding to the word matching the keyword from the recording medium  70  (step S 230  (a reading step)). The user may be able to specify a timing at which the information is read. 
     After step S 230 , the output unit  140  outputs the object information, the image information, the sound information, and the text information read by the reading unit  80 . The display unit  90  displays the object information, the image information, and the text information output by the output unit  140  such that the object information, the image information, and the text information are associated with each other. Also, the sound output unit  100  outputs a sound based on the sound information output by the output unit  140  (step S 235  (an output step, a display step, and a sound output step)). 
     When the information recording system  10   d  does not include the image acquisition unit  30 , the processing in step S 205  is not performed. Also, in step S 215 , the recording unit  60  records the object information, the sound information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the sound information, the text information, the conversion candidate word, and the time point information are associated with each other. In step S 230 , the reading unit  80  reads the object information, the sound information, and the text information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . In step S 235 , the output unit  140  outputs the object information, the sound information, and the text information read by the reading unit  80  in step S 230 . Also, in step S 235 , the display unit  90  displays the object information and the text information output by the output unit  140  such that the object information and the text information are associated with each other. No text information may be output from the information recording device  120 . Also, in step S 235 , the sound output unit  100  outputs a sound based on the sound information read by the reading unit  80  in step S 230 . 
     When the information recording system  10   d  does not include the sound output unit  100  and the recording unit  60  does not record sound information, the recording unit  60  records the object information, the image information, the text information, the conversion candidate word, and the time point information on the recording medium  70  such that the object information, the image information, the text information, the conversion candidate word, and the time point information are associated with each other in step S 215 . In step S 230 , the reading unit  80  reads the object information, the image information, and the text information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . In step S 235 , the output unit  140  outputs the object information, the image information, and the text information read by the reading unit  80  in step S 230 . Also, in step S 235 , the display unit  90  displays the object information, the image information, and the text information output by the output unit  140  such that the object information, the image information, and the text information are associated with each other. No text information may be output from the information recording device  120 . 
     At least one of the sound processing unit  50  and the recording medium  70  may be disposed outside the information recording device  120 . When the sound processing unit  50  is disposed outside the information recording device  120 , the text information from the sound processing unit  50  is input to the input unit  130 . The recording medium  70  may be attachable to and detachable from the information recording device  120 . The information recording device  120  may have a network interface and the information recording device  120  may be connected to the recording medium  70  via a network. The information recording device  120  may have a wireless communication interface and the information recording device  120  may be connected to the recording medium  70  through wireless communication. 
     The information recording device  120  may not include the output unit  140 . For example, the recording medium  70  is configured so that the recording medium  70  can be attached to and detached from the information recording device  120 . The reading unit  80  reads the object information, the image information, the sound information, and the text information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . The recording unit  60  records the object information, the image information, the sound information, and the text information read by the reading unit  80  on the recording medium  70  such that the object information, the image information, the sound information, and the text information are associated with each other. When the recording medium  70  is detached from the information recording device  120  and is attached to a device outside the information recording device  120 , the device can use the information recorded on the recording medium  70 . When the information recording device  120  does not include the output unit  140 , the information recording device  120  does not perform the processing in step S 235 . 
     As described above, object information is input to the input unit  130  and image information indicating a type of situation in which the object information was acquired is input to the input unit  130 . The input object information and image information are recorded on the recording medium  70  by the recording unit  60 . Thereby, the information recording device  120  can record visual information indicating a type of situation in which the object information was acquired. 
     As described above, the conversion candidate word generated in the process of converting the sound information into the text information is recorded on the recording medium  70  by the recording unit  60 . The search unit  65  searches for a keyword received by the keyword reception unit  55  in the text information and the conversion candidate word and extracts a word matching the keyword from the words within the text information and the conversion candidate word. Even when a word erroneously recognized in the sound recognition process cannot be extracted from the text information during a search, the search unit  65  can extract a desired word from the conversion candidate word corresponding to the erroneously recognized word. Therefore, the information recording device  120  can reduce omissions in a word search in the text information. As a result, the information recording device  120  can provide the user with the object information, the image information, the sound information, and the text information corresponding to the keyword received by the keyword reception unit  55 . The effect obtained in the information recording system  10  of the first embodiment can be similarly obtained also in the information recording device  120  of the second embodiment. 
     The matters disclosed in the first to third modified examples of the first embodiment may be similarly applied to the information recording device  120  of the second embodiment. Therefore, the information recording system  10   d  may include the situation information acquisition unit  110  and the situation information acquired by the situation information acquisition unit  110  may be input to the input unit  130 . Alternatively, the information recording device  120  may include an event detection unit  75 . 
     Third Embodiment 
       FIG. 19  shows a configuration of an information recording system  10   e  according to a third embodiment of the present invention. In terms of the configuration shown in  FIG. 19 , differences from the configuration shown in  FIG. 1  will be described. 
     The information recording system  10   e  shown in  FIG. 19  does not include the object information acquisition unit  20  and the image acquisition unit  30  in the information recording system  10  shown in  FIG. 1 . A recording unit  60  records sound information, text information, conversion candidate word, and time point information on a recording medium  70  such that the sound information, the text information, the conversion candidate word, and the time point information are associated with each other. A reading unit  80  reads text information including a first part corresponding to a word matching the keyword from the recording medium  70 . A display unit  90  displays the text information read by the reading unit  80  such that the first part and a second part other than the first part can be distinguished. 
     Also, the reading unit  80  reads the sound information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . A sound output unit  100  outputs a sound based on the sound information read by the reading unit  80 . 
     The information recording system  10   e  may not include the sound output unit  100 . In this case, the recording unit  60  records the text information and the conversion candidate word on the recording medium  70  such that the text information and the conversion candidate word are associated with each other. The reading unit  80  reads text information including the first part corresponding to the word matching the keyword from the recording medium  70 . Because the conversion candidate word is associated with a determined word constituting the text information, no time point information may be recorded. 
     In terms of points other than the above, the configuration shown in  FIG. 19  is similar to the configuration shown in  FIG. 1 . 
       FIG. 20  shows a procedure of processing of the information recording system  10   c . In terms of the processing shown in  FIG. 20 , differences from the processing shown in  FIG. 2  will be described. 
     The processing in steps S 100  and S 105  shown in  FIG. 2  is not performed. After step S 110 , the recording unit  60  records sound information, text information, conversion candidate word, and time point information stored in the buffer in the recording unit  60  on the recording medium  70  such that the sound information, the text information, the conversion candidate word, and the time point information are associated with each other (step S 160  (a recording step)). 
     After step S 125 , the reading unit  80  reads the text information including a first part corresponding to a word matching a keyword from the recording medium  70 . Also, the reading unit  80  reads the sound information associated with the time point information corresponding to the word matching the keyword from the recording medium  70  (step S 165  (a reading step)). 
     After step S 165 , the display unit  90  displays the text information read by the reading unit  80  such that the first part can be distinguished from the second part other than the first part. Also, the sound output unit  100  outputs a sound based on the sound information read by the reading unit  80  (step S 170  (a display step and a sound output step)). 
     When the information recording system  10   e  does not include the sound output unit  100 , the recording unit  60  records the text information and the conversion candidate word on the recording medium  70  such that the text information and the conversion candidate word are associated with each other in step S 160 . In step S 165 , the reading unit  80  reads text information including the first part corresponding to the word matching the keyword from the recording medium  70 . In step S 170 , the display unit  90  displays the text information read by the reading unit  80  such that the first part and the second part other than the first part can be distinguished. 
     In terms of points other than the above, the processing shown in  FIG. 20  is similar to the processing shown in  FIG. 2 . 
     An example of a search by a search unit  65  will be described with reference to  FIG. 21 . In  FIG. 21 , a graph of a sound signal A 20  is shown. In the graph, the horizontal direction represents time and the vertical direction represents amplitude. During a period T 30 , a period T 31 , and a period T 32 , the amplitude of the sound signal exceeds the threshold value. During these periods, the user utters sounds. 
     From the text information associated with the time point information of the period T 30 , conversion candidate words are generated by a sound processing unit  50 . In the example shown in  FIG. 21 , three conversion candidate words “experiment”, “case”, and “examination” are associated with the word “ten” within the text information which is a determined word. Likewise, three conversion candidate words “securities”, “condition”, and “experiment” are associated with the word “requirements” within the text information. Likewise, a conversion candidate word “return” is associated with the word “change” within the text information. The word “change” is pronounced as “henkou” in Japanese. The word “return” is pronounced as “hennou” in Japanese. 
     Likewise, conversion candidate words are generated by the sound processing unit  50  from the text information associated with the time point information of each of the period T 30  and the period T 31 . In  FIG. 21 , these conversion candidate words are omitted. 
     When the keyword “experiment condition” is specified, the search unit  65  searches for the keyword in the text information and the conversion candidate word. The search unit  65  extracts a conversion candidate word matching the word “experiment” in the keyword and a conversion candidate word matching the word “condition” in the keyword from the conversion candidate words corresponding to the period T 30 . Also, the search unit  65  extracts words matching the term “experiment condition” within the keyword from the text information corresponding to the period T 32 . 
       FIG. 22  shows text information displayed by the display unit  90 . The display unit  90  displays text information TX 10  corresponding to the period T 30 , text information TX 11  corresponding to the period T 31 , and text information TX 12  corresponding to the period T 32 . The display unit  90  displays a frame F 10  in the first part corresponding to the word matching the keyword in the text information TX 10 . The first part in the text information TX 10  includes a determined word corresponding to a conversion candidate word matching the keyword. Also, the display unit  90  displays a frame F 11  in the first part corresponding to the word matching the keyword in the text information TX 12 . The first part in the text information TX 12  includes a determined word matching the keyword. In the text information TX 10 , a part other than the first part where the frame F 10  is displayed constitutes a second part that does not include the word corresponding to the word matching the keyword. The text information TX 11  constitutes the second part. In the text information TX 12 , a part other than the first part in which the frame F 11  is displayed constitutes the second part. 
     The display unit  90  may display the first part in a first display form and the second part in a second display form different from the first display form. For example, the display unit  90  displays the first part such that the first part is emphasized more than the second part. For example, the display unit  90  displays the word within the first part in a color different from that of the word within the second part. The display unit  90  may display the word within the first part with characters thicker than those of the word within the second part. The display unit  90  may display the word within the first part with characters larger than those of the word within the second part. A method of distinguishing the first part from the second part is not limited to the above-described method. 
     The information recording system  10   e  can reduce omissions in a word search in text information. As a result, the information recording system  10   e  can provide the user with text information corresponding to the keyword received by a keyword reception unit  55 . 
     As described above, the first part corresponding to the word matching the keyword and the second part other than the first part in the text information are distinguished and displayed. Thus, the user can easily check the search result. 
     The matters disclosed in the second modification of the first embodiment may be similarly applied to the information recording system  10   c  of the third embodiment. 
     Fourth Embodiment 
       FIG. 23  shows a configuration of an information recording system  10   f  according to a fourth embodiment of the present invention. In terms of the configuration shown in  FIG. 23 , differences from the configuration shown in  FIG. 15  will be described. 
     The information recording system  10   f  shown in  FIG. 23  does not include the object information acquisition unit  20  and the image acquisition unit  30  in the information recording system  10   d  shown in  FIG. 15 . 
     In terms of points other than the above, the configuration shown in  FIG. 23  is similar to the configuration shown in  FIG. 15 . 
     A configuration of an information recording device  120   f  is similar to that of the  25  information recording device  120  shown in  FIG. 17  except for the following points. Sound information from a sound acquisition unit  40  is input to an input unit  130 . A recording unit  60  records sound information, text information, conversion candidate word, and time point information on a recording medium  70  such that the sound information, the text information, the conversion candidate word, and the time point information are associated with each other. A reading unit  80  reads text information including a part corresponding to a word matching the keyword from the recording medium  70 . Also, the reading unit  80  reads the sound information associated with the time point information corresponding to the word matching the keyword from the recording medium  70 . An output unit  140  outputs the sound information and the text information read by the reading unit  80 . That is, the output unit  140  outputs the text information to a display unit  90  and outputs the sound information to a sound output unit  100 . 
     The information recording system  10   f  may not include the sound output unit  100 . In this case, the recording unit  60  records the text information and the conversion candidate word on the recording medium  70  such that the text information and the conversion candidate word are associated with each other. The reading unit  80  reads the text information including a part corresponding to a word matching the keyword from the recording medium  70 . The output unit  140  outputs the text information read by the reading unit  80 . Because the conversion candidate word is associated with a determined word constituting the text information, no time point information may be recorded. 
       FIG. 24  shows a procedure of processing of the information recording device  120   f . In terms of the processing shown in  FIG. 24 , differences from the processing shown in  FIG. 18  will be described. 
     The processing in steps S 200  and S 205  shown in  FIG. 18  is not performed. After step S 210 , the recording unit  60  records sound information, text information, conversion candidate word, and time point information stored in a buffer within the recording unit  60  on the recording medium  70  such that the sound information, the text information, the conversion candidate word, and the time point information are associated with each other (step S 215  (a recording step)). 
     After step S 225 , the reading unit  80  reads the text information including a first part corresponding to a word matching a keyword from the recording medium  70 . Also, the reading unit  80  reads the sound information associated with the time point information corresponding to the word matching the keyword from the recording medium  70  (step S 245 ). 
     After step S 245 , the output unit  140  outputs the sound information and the text information read by the reading unit  80 . The display unit  90  displays the text information output by the output unit  140  such that the first part can be distinguished from a second part other than the first part. Also, the sound output unit  100  outputs a sound based on the sound information read by the reading unit  80  (step S 250  (an output step, a display step, and a sound output step)). 
     When the information recording system  10   f  does not include the sound output unit  100 , the recording unit  60  records the text information and the conversion candidate word on the recording medium  70  such that the text information and the conversion candidate word are associated with each other in step S 240 . In step S 245 , the reading unit  80  reads the text information including the first part corresponding to the word matching the keyword from the recording medium  70 . In step S 250 , the output unit  140  outputs the text information read by the reading unit  80 . Also, in step S 250 , the display unit  90  displays the text information read by the reading unit  80  such that the first part and the second part other than the first part can be distinguished. 
     In terms of points other than the above, the processing shown in  FIG. 24  is similar to the processing shown in  FIG. 18 . 
     The information recording device  120   f  can reduce omissions in a word search in text information. As a result, the information recording device  120   f  can provide the user with text information corresponding to the keyword received by a keyword reception unit  55 . 
     As described above, in the text information, the first part corresponding to the word matching the keyword and the second part other than the first are distinguished and displayed. Thus, the user can easily check a search result. 
     The matters disclosed in the second modified example of the first embodiment may be similarly applied to the information recording system  10   f  of the fourth embodiment. 
     (Supplement) 
     According to an aspect of the present invention, an information recording device includes an input unit, a sound processing unit, a recording unit, a keyword reception unit, a search unit, and a reading unit. Sound information based on a sound uttered by a user is input to the input unit. The sound processing unit converts the sound information input to the input unit into text information and generates at least one conversion candidate word corresponding to the sound in a process of converting the sound information into the text information. The recording unit records the text information and the conversion candidate word on a recording medium such that the text information and the conversion candidate word are associated with each other. The keyword reception unit receives a keyword. The search unit searches for the keyword received by the keyword reception unit in the text information and the conversion candidate word and extracts a word matching the keyword from words within the text information and the conversion candidate word. The reading unit reads the text information including a part corresponding to the word matching the keyword from the recording medium. 
     According to an aspect of the present invention, an information recording device includes an input unit, a sound processing unit, a recording unit, a keyword reception unit, a search unit, and a reading unit. Object information about an object and sound information based on a sound uttered by an observer who observes the object are input to the input unit. The sound processing unit converts the sound information input to the input unit into text information and generates at least one conversion candidate word corresponding to the sound in a process of converting the sound information into the text information. The recording unit records the object information, the text information, the conversion candidate word, and time point information on a recording medium such that the object information, the text information, the conversion candidate word, and the time point information are associated with each other. The time point information indicates a time point at which the object information was acquired and a time point at which the sound information based on the text information was acquired. The keyword reception unit receives a keyword. The search unit searches for the keyword received by the keyword reception unit in the text information and the conversion candidate word and extracts a word matching the keyword from words within the text information and the conversion candidate word. The reading unit reads the object information associated with the time point information corresponding to the word matching the keyword from the recording medium. 
     According to an aspect of the present invention, an information recording method includes an object information acquisition step, a sound acquisition step, a sound processing step, a recording step, a keyword reception step, a search step, a reading step, and a display step. In the object information acquisition step, an object information acquisition unit acquires object information about an object. In the sound acquisition step, a sound acquisition unit acquires sound information based on a sound uttered by an observer who observes the object. In the sound processing step, a sound processing unit converts the sound information acquired by the sound acquisition unit into text information and generates at least one conversion candidate word corresponding to the sound in a process of converting the sound information into the text information. In the recording step, a recording unit records the object information, the text information, the conversion candidate word, and time point information on a recording medium such that the object information, the text information, the conversion candidate word, and the time point information are associated with each other. The time point information indicates a time point at which the object information was acquired and a time point at which the sound information that is a source of the text information was acquired. In the keyword reception step, a keyword reception unit receives a keyword. In the search step, a search unit searches for the keyword received by the keyword reception unit in the text information and the conversion candidate word and extracts a word matching the keyword from words within the text information and the conversion candidate word. In the reading step, a reading unit reads the object information associated with the time point information corresponding to the word matching the keyword from the recording medium. In the display step, a display unit displays the text information read by the reading unit. 
     According to an aspect of the present invention, an information recording method includes an input step, a sound processing step, a recording step, a keyword reception step, a search step, and a reading step. In the input step, sound information based on a sound uttered by a user is input to an input unit. In the sound processing step, a sound processing unit converts the sound information input to the input unit into text information and generates at least one conversion candidate word corresponding to the sound in a process of converting the sound information into the text information. In the recording step, a recording unit records the text information and the conversion candidate word on a recording medium such that the text information and the conversion candidate word are associated with each other. In the keyword reception step, a keyword reception unit receives a keyword. In the search step, a search unit searches for the keyword received by the keyword reception unit in the text information and the conversion candidate word and extracts a word matching the keyword from words within the text information and the conversion candidate word. In the reading step, a reading unit reads the text information including a part corresponding to the word matching the keyword from the recording medium. 
     According to an aspect of the present invention, an information recording method includes an input step, a sound processing step, a recording step, a keyword reception step, a search step, and a reading step. In the input step, object information about an object and sound information based on a sound uttered by an observer who observes the object are input to an input unit. In the sound processing step, a sound processing unit converts the sound information input to the input unit into text information and generates at least one conversion candidate word corresponding to the sound in a process of converting the sound information into the text information. In the recording step, a recording unit records the object information, the text information, the conversion candidate word, and time point information on a recording medium such that the object information, the text information, the conversion candidate word, and the time point information are associated with each other. The time point information indicates a time point at which the object information was acquired and a time point at which the sound information that is a source of the text information was acquired. In the keyword reception step, a keyword reception unit receives a keyword. In the search step, a search unit searches for the keyword received by the keyword reception unit in the text information and the conversion candidate word and extracts a word matching the keyword from words within the text information and the conversion candidate word. In the reading step, a reading unit reads the object information associated with the time point information corresponding to the word matching the keyword from the recording medium. 
     While preferred embodiments of the invention have been described and shown above, it should be understood that these are exemplars of the invention and are not to be considered as limiting. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit or scope of the present invention. Accordingly, the invention is not to be considered as being limited by the foregoing description, and is only limited by the scope of the appended claims.