Patent Publication Number: US-2018054551-A1

Title: Observation apparatus, observation method and observation system

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2016-159972, filed on Aug. 17, 2016, the entire contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an observation apparatus, an observation method and an observation system. 
     2. Description of the Related Art 
     An apparatus wherein a culture vessel is statically placed in an incubator and images of cultured cells or the like in the culture vessel are taken, is known in the art. For example, Jpn. Pat. Appln. KOKAI Publication No. 2005-295818 discloses a technique related to an apparatus which takes a number of images while moving a camera (imaging unit) inside an incubator so as to take images of cells existing in a wide range of a culture vessel. 
     BRIEF SUMMARY OF THE INVENTION 
     According to a first aspect of the present invention, there is provided an observation apparatus including an imaging unit configured to take an image of an object, a driving mechanism configured to move the imaging unit, a control circuit configured to control an operation of the driving mechanism and an operation of the imaging unit in association with each other, and a position designation unit configured to designate a priority observation position in part of the object, wherein the control circuit moves the imaging unit to the priority observation position on a priority basis when the control circuit controls the operation of the driving mechanism and the operation of the imaging unit in association with each other to observe a predetermined region including the part of the object. 
     According to a second aspect of the present invention, there is provided an observation method in which an operation of an imaging unit configured to take an image of an object and an operation of a driving mechanism configured to move the imaging unit are controlled in association with each other, the method including designating a priority observation position in part of the object; and moving the imaging unit to the priority observation position on a priority basis when the operation of the driving mechanism and the operation of the imaging unit are controlled in association with each other to observe a predetermined region including the part of the object. 
     According to a third aspect of the present invention, there is provided an observation system including the observation apparatus according to the first aspect wherein the apparatus further includes a communication device, and a controller configured to communicate with the observation apparatus through the communication device and control an operation of the observation apparatus. 
     Advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the invention. 
         FIG. 1  is a schematic perspective view showing an exemplary configuration of an observation system according to a first embodiment of the present invention. 
         FIG. 2  is a schematic block diagram of the exemplary configuration of the observation system according to the first embodiment. 
         FIG. 3  is a schematic side view showing an exemplary configuration of a sample and its neighboring portions in an observation apparatus included in the observation system according to the first embodiment. 
         FIG. 4  is a plan view of a controller that configures the observation system according to the first embodiment, which schematically shows an exemplary configuration of an input/output device of the controller. 
         FIG. 5A  illustrates a first part of a flowchart showing an example of an observation apparatus control process performed by the observation apparatus according to the first embodiment. 
         FIG. 5B  illustrates a second part of the flowchart showing an example of an observation apparatus control process performed by the observation apparatus according to the first embodiment. 
         FIG. 6  illustrates backlash correction in the movement direction of an imaging unit of the observation apparatus according to the first embodiment. 
         FIG. 7  illustrates image acquisition in the observation apparatus according to the first embodiment. 
         FIG. 8  illustrates a movement pattern of the imaging unit in the observation apparatus according to the first embodiment. 
         FIG. 9  is a schematic diagram showing an exemplary configuration of observation data acquired by the observation system according to the first embodiment. 
         FIG. 10A  illustrates a first part of a flowchart showing an example of a controller control process performed by the controller according to the first embodiment. 
         FIG. 10B  illustrates a second part of the flowchart showing an example of a controller control process performed by the controller according to the first embodiment. 
         FIG. 11  illustrates an example of an operation of designating an origin when an observation is started using the controller according to the first embodiment. 
         FIG. 12  is a schematic perspective view showing an exemplary configuration of an observation system according to a second embodiment of the present invention. 
         FIG. 13  illustrates initial position determination in an observation apparatus according to the second embodiment. 
         FIG. 14  illustrates auxiliary driving in the observation apparatus according to the second embodiment. 
         FIG. 15  illustrates response wait type driving in the observation apparatus according to the second embodiment. 
         FIG. 16A  illustrates a state in which a belt is not extended in the observation apparatus according to the second embodiment. 
         FIG. 16B  illustrates a state in which the belt is extended in the observation apparatus according to the second embodiment. 
         FIG. 17A  illustrates images combined when the belt is not extended in the observation apparatus according to the second embodiment. 
         FIG. 17B  illustrates images combined when the belt is extended in the observation apparatus according to the second embodiment. 
         FIG. 18A  illustrates a first part of a flowchart showing an example of an observation apparatus control process performed by the observation apparatus according to the second embodiment. 
         FIG. 18B  illustrates a second part of the flowchart showing an example of an observation apparatus control process performed by the observation apparatus according to the second embodiment. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     First Embodiment 
     A first embodiment of the present invention will be described with reference to the accompanying drawings. The observation system according to the first embodiment is a system which takes images of a cell and the like, which are being cultured, and which records the taken images. 
     (Configuration of Observation System) 
     As shown in  FIG. 1 , the observation system  1  according to the first embodiment includes an observation apparatus  100  and a controller  200 . 
     The observation apparatus  100  includes a casing  101  that is shaped substantially like a plate. The observation apparatus  100  is placed in, for example, an incubator (not shown) or a clean bench (not shown) for operations. On the top of the observation apparatus  100 , a sample  300  to be observed is placed. For the sake of description, an X-axis and a Y-axis perpendicular to each other are defined in a plane parallel to the surface of the observation apparatus on which the sample  300  is placed, and a Z-axis is defined as an axis perpendicular to both the X-axis and the Y-axis. 
     On the top of the casing  101  of the observation apparatus  100 , a transparent plate  102  is provided. The sample  300  is mounted on the transparent plate  102 . Inside the casing  101  of the observation apparatus  100 , an imaging unit  110  is provided. The imaging unit  110  takes an image of the sample  300  through the transparent plate  102  to acquire the image of the sample  300 . 
     The controller  200  is provided outside the incubator. The observation apparatus  100  and the controller  200  communicate with each other wirelessly or by a cable. The controller  200  controls the operation of the observation apparatus  100 . 
     (Sample) 
     An example of the sample  300  to be observed by the observation system  1  will be described. The sample  300  includes a vessel  301 . A culture medium  302  is in the vessel  301 , and cells  303  are cultured in the culture medium  302 . The vessel  301  is a petri dish, a culture flask, a multiwell plate, or the like. The vessel  301  is a culture vessel for culturing a living specimen, for example. The vessel  301  is not limited to any specific shape, size or the like. The culture medium  302  may be either a liquid medium or a solid medium. The cells  303  to be observed may be either adhesive cells or floating cells. Alternatively, the cells  303  may be spheroids or tissues. In addition, the cells  303  may be derived from any living substance or may be bacteria or the like. As described above, the sample  300  includes a living sample which is either the living substance itself or is derived from the living substance. On the top of the vessel  301 , a vessel lid  304  is placed. The vessel lid  304  reflects illumination light, which will be described later. 
     (Observation Apparatus) 
     On the top of the casing  101  of the observation apparatus  100 , the transparent plate  102  made of, e.g. glass is provided. The sample  300  is statically placed on this transparent plate  102 .  FIG. 1  shows that the top of the casing  101  is entirely formed of a transparent plate. The observation apparatus  100  may be so configured that part of the top of the casing  101  is a transparent plate and the remaining part thereof is opaque. 
     Various structural elements of the observation apparatus  100  are provided inside the casing  101 . The interior of the incubator has a temperature of 37° C. and a humidity of 95%. Since the observation apparatus  100  is used in the environment of high ambient temperature and humidity, the casing  101  is designed to have an air-tight structure. Although the first embodiment assumes that the observation apparatus  100  is used inside the incubator and emphasizes that it is used mainly to observe cells, the observation apparatus  100  is a generally-used one which is resistant to a severe use environment and which is configured to enlarge details of an object to be observed. 
     The imaging unit  110  in the casing  101  is fixed and supported on a support member  103 . The imaging unit  110  is disposed to take an image of the region where the sample  300  is present and thus acquire a local image of the sample  300 . 
     An illumination unit  120  for illuminating the sample  300  is fixed and supported close to the imaging unit  110  of the support member  103 . The illumination unit  120  is disposed to emit illumination light in the direction toward the transparent plate  102 , namely, in the direction toward the sample  300 . 
     The support member  103  on which the imaging unit  110  and the illumination unit  120  are fixed is moved by a driving mechanism  130 . The driving mechanism  130  includes an X feed screw  131  and an X actuator  132  for moving the support member  103  in the X-axis direction. The driving mechanism  130  also includes a Y feed screw  133  and a Y actuator  134  for moving the support member  103  in the Y-axis direction. In other words, the observation apparatus  100  includes the imaging unit  110  for taking an image of an object such as the sample  300  and the driving mechanism  130  for moving the imaging unit  110 . The operations of the driving mechanism  130  and imaging unit  110  are controlled in association with a control unit to be described later. The control unit needs not be one, but a driving control unit and an imaging control unit can be associated with each other in a predetermined sequence. The position of the imaging unit  110  can be controlled while determining an absolute position; however, there are a configuration and a method for controlling the position relatively by the driving amounts of the actuators. In this case, it is important where a reference position or an initial position is set. The observation apparatus  100  according to the first embodiment is so configured that the initial position can be determined using a magnetic sensor, a photocoupler, a specific-position marker or the like, which are not shown. If it is determined how much the actuators are driven, the position of the imaging unit  110  can correctly be adjusted and controlled. 
     An operation member  140  is provided on the front of the casing  101  to instruct the driving mechanism  130  to move the support member  103  in the X-axis direction and Y-axis direction. The front of the casing  101  is opposed to an incubator opening/closing section for setting the observation apparatus  100  into the incubator. A user can thus operate the operation member  140  through the incubator opening/closing section. 
     The operation member  140  can be configured as a slide button for providing an instruction to move the imaging unit  110  in the X-axis direction and a slide button for providing an instruction to move it in the Y-axis direction and can also be configured by a cross-direction key or the like. The user can thus move the imaging unit  110  to his or her desired or favorite position as a priority observation position and observe an object intensively and on a priority basis. Since, however, this method allows an observation only in a narrow range, the observation apparatus  100  is configured to take an image of each section in a specific sequence and observe all or part of an observation area corresponding to a movable portion within a specific range. In other words, the observation apparatus  100  includes an observation apparatus control circuit  160  (described later) serving as a control unit to control the driving mechanism  130  and imaging unit  110  in time sequence according to a specific rule in order to observe a predetermined region including at least part of the observation area from the priority observation position. 
     When the user moves the imaging unit  110  to the priority observation position, the control unit may not be able to understand the relative positional relationship between the priority observation position and the foregoing reference position or initial position due to backlash and play of the driving mechanism  130 . In the observation apparatus  100 , therefore, a control for removing a backlash is performed in the priority observation position, or an initial positioning is performed to determine a relative position. In this way, the priority observation position is considered to be a driving mechanism driving amount from the initial position, or an error of the drive control position of the driving mechanism  130  can be canceled. The reference position or initial position can be determined by the output of sensors or the like, which are positioned at the drive ends of the imaging unit  110  in the X and Y directions. 
     If the priority observation position is stored as an actuator driving amount with reference to the initial position, the same region can be monitored repeatedly even after various types of drive control. There is another method for observing a specific region by obtaining a movement error by removing a backlash and a flexure and moving the imaging unit  110  to correct the error. The observation apparatus  100  further includes an observation apparatus storage circuit  170  (described later) as a storage circuit for storing the priority observation position and the movement error. Thus, both the priority observation in a given position and drive association observation in a specific range can be made correctly. 
     The imaging position in the Z-axis direction is changed by changing the focus position of an imaging optical system of the imaging unit  110 . In other words, the imaging optical system includes a focus adjustment mechanism for moving a focusing lens in the direction of the optical axis. In place of the focus adjustment mechanism or in combination therewith, the driving mechanism  130  may include a Z feed screw, a Z actuator, etc. for moving the support member  103  in the Z-axis direction. The moving of the support member  103  in the Z-axis direction may be controlled relatively from the initial position to move to the absolute position by a stepping motor, as in the X-axis and Y-axis directions. 
     A circuit group  104  for controlling the imaging unit  110 , illumination unit  120  and driving mechanism  130  are provided inside the casing  101 . The circuit group  104  is provided with an observation apparatus communication device  150 . The observation apparatus communication device  150  is, for example, a device which communicates with the controller  200  by wireless. The communications are wireless communications using Wi-Fi (registered trademark), Bluetooth (registered trademark) or the like. The observation apparatus  100  and the controller  200  may be connected by a cable, and cable communications may be performed between them. As described above, the imaging unit  110  (which generates image data by photographing an object through the transparent plate  102 ) and the driving mechanism  130  (which moves the imaging unit  110 ) are provided inside the casing  101 . This structure increases reliability, facilitates handling and cleaning, and prevents contamination and the like. 
     The observation system  1  will be described further in detail with reference to  FIG. 2  showing functional blocks of the observation system  1 . 
     The imaging unit  110  includes an imaging optical system  111  and an image sensor  112 . The imaging unit  110  generates image data based on an image formed on the imaging plane of the image sensor  112  by the imaging optical system  111 . 
     The illumination unit  120  includes an illumination optical system  121  and a light source  122 . The light source  122  emits illumination light. The sample  300  is irradiated with the illumination light through the illumination optical system  121 . The light source  122  includes, for example, an LED. Though it has been described that the illumination unit  120  is fixed on the support member  103 , a light radiation portion of the illumination optical system  121  has only to be placed on the support member  103  and, for example, the light source  122  can also be placed anywhere in the observation apparatus  100 . 
       FIG. 3  is a schematic diagram showing the sample  300  viewed from one side thereof. As shown in  FIG. 3 , the vessel lid  304 , which is made of transparent plastics and provided on the top of the vessel  301 , is irradiated with the illumination light emitted from the illumination optical system  121  of the illumination unit  120  on the support member  103 . The vessel lid  304  transmits part of the illumination light and reflects the other. The vessel lid  304  can thus be designed as a reflector plate. The light reflected by the vessel lid  304  illuminates the cells  303  and enters the imaging optical system  111  of the imaging unit  110 . The region illuminated by the illumination light covers at least a local area of the sample  300  which corresponds to one image taken by the imaging unit  110 . 
     As shown in  FIG. 2 , the observation apparatus  100  includes an observation apparatus control circuit  160 , an observation apparatus storage circuit  170  and an image processing circuit  180 , in addition to the foregoing imaging unit  110 , illumination unit  120 , driving mechanism  130 , operation member  140  and observation apparatus communication device  150 . The observation apparatus communication device  150 , observation apparatus control circuit  160 , observation apparatus storage circuit  170  and image processing circuit  180  are arranged, for example, in the circuit group  104  described above. 
     The observation apparatus control circuit  160  controls the operation of each of the elements of the observation apparatus  100 . The observation apparatus control circuit  160  includes functions as a position control unit  161 , an imaging control unit  162 , an illumination control unit  163 , a recording control unit  164 , a communication control unit  165  and an observation control unit  166 . 
     The position control unit  161  controls the driving mechanism  130  to control the position of the support member  103 . The imaging control unit  162  controls the imaging unit  110  to cause the imaging unit  110  to take an image of the sample  300 . In other words, the driving mechanism  130  and imaging unit  110  of the observation apparatus  100  are controlled in association with the position control unit  161  and imaging control unit  162  of the observation apparatus control circuit  160 . 
     In this association control, it is important to control a position correctly. This control may be position control to be performed while determining an absolute position and relative control to be performed by the driving amounts of the actuators. It is important which position is a reference position or the initial position. Thus, the initial position can be determined by a magnetic sensor, a photocoupler, a specific-position marker or the like, neither of which is shown. The reference position or the initial position has only to be determined by the output of a sort of sensor, such as a magnetic sensor, a photocoupler, and a specific-position marker, which is provided by positioning at the drive ends of the imaging unit  110  in the X and Y directions. In this case, however, the imaging unit  110  needs to be configured by a member to which the sensor reacts or needs to have a structure to which the sensor reacts. If it is determined how much the actuators are driven from the reference position or the initial position, the position of the imaging unit  110  can correctly be adjusted and controlled. This position adjustment data can be stored in the observation apparatus storage circuit  170 . 
     The illumination control unit  163  controls the operation of the illumination unit  120 . The recording control unit  164  controls recording of data obtained by the observation apparatus  100  on the observation apparatus storage circuit  170 . The communication control unit  165  controls communications with the controller  200 , which are performed through the observation apparatus communication device  150 . The observation control unit  166  controls the overall observation, including observation timings and the number of times the observation is made. 
     The observation apparatus storage circuit  170  includes a storage medium such as a semiconductor memory to store, for example, programs and various parameters used by the observation apparatus control circuit  160 . The observation apparatus storage circuit  170  also stores data, etc. obtained by the observation apparatus  100 . 
     The image processing circuit  180  performs various kinds of image processing for the image data obtained by the imaging unit  110 . The data processed by the image processing circuit  180  is stored in, e.g. the observation apparatus storage circuit  170  or transmitted to the controller  200  through the observation apparatus communication device  150  as a taken image. 
     (Controller) 
     The controller  200  is a personal computer (PC), a tablet type information terminal or the like. In  FIG. 1 , a tablet type information terminal is depicted. 
     The controller  200  of the tablet type information terminal is provided with, for example, an input/output device  210  including a display device  211  (e.g., a liquid crystal display) and an input device  212  (e.g., a touch panel). The touch panel can be placed on almost all the display screen of the display device  211 . The input device  212  is not limited to the touch panel but may include a switch, a dial, a keyboard, a mouse, etc. 
     The controller  200  is provided with a controller communication device  220 . The controller communication device  220  is a device which communicates with the observation apparatus communication device  150 . The observation apparatus  100  and the controller  200  communicate with each other through the observation apparatus communication device  150  and the controller communication device  220 . 
     The controller  200  includes a controller control circuit  230  and a controller storage circuit  240 . The controller control circuit  230  controls each of the elements of the controller  200 . The controller storage circuit  240  includes a storage medium such as a semiconductor memory to store, for example, programs and various parameters used by the controller control circuit  230 . The controller storage circuit  240  also stores data obtained by the observation apparatus  100  and received from the observation apparatus  100 . The controller storage circuit  240  may store positioning parameters. 
     The controller control circuit  230  includes functions as a system control unit  231 , a display control unit  232 , a recording control unit  233  and a communication control unit  234 . The system control unit  231  performs various operations for controlling the observation of the sample  300 . The display control unit  232  controls the display device  211 . The display control unit  232  causes the display device  211  to display the necessary information and the like. The recording control unit  233  controls the operation of recording information in the controller storage circuit  240 . The communication control unit  234  controls the communications with the observation apparatus  100 , which are performed through the controller communication device  220 . 
     The display device  211  of the input/output device displays, for example, an observation screen  213  as shown in  FIG. 4 . The observation screen  213  includes a taken image display section  214 , an imaging position display section  215  and an operation button display section  216 . 
     The taken image display section  214  is a region to display image data received from the observation apparatus  100 . The display control unit  232  of the controller control circuit  230  displays, in the taken image display section  214 , one of the image data that the imaging unit  110  moves to acquire from a plurality of local areas, as a local image. The display control unit  232  can combine a plurality of local images acquired by the imaging unit  110  and display a whole image. The display control unit  232  may display, in the taken image display section  214 , an image size index  214 A to indicate which of the local image and the whole image is displayed. The display control unit  232  switches the display between the local image and the whole image based on the operation information input through the input device  212  in response to a touch operation of the image size index  214 A. 
     The imaging position display section  215  is a region to display which portion of the observation apparatus  100  corresponds to an image displayed in the taken image display section  214 , namely a region to display an imaging position as a map. The display control unit  232  displays a position index  215 A in the imaging position display section  215  to indicate which region of the observation apparatus  100  corresponds to an image being displayed in the taken image display section  214 . The position index  215 A can be described as character information  215 B. In the example of  FIG. 4 , the character information  215 B represents the position of the position index  215 A by X and Y coordinates. The display control unit  232  switches a local image to be displayed in the taken image display section  214 , based on the operation information input through the input device  212  in response to a touch operation of the imaging position display section  215 . As will be described later, the touch operation of the imaging position display section  215  allows a priority observation position (origin of start of observation) to be designated. 
     The operation button display section  216  is a region to display various operation buttons when necessary. The display control unit  232  displays an image of a necessary operation button in the operation button display section  216  according to the situation of an operation controlled by the observation apparatus control circuit  160 . The observation apparatus control circuit  160  controls an operation selected and designated by a user, based on the operation information input through the input device  212  in response to a touch operation in a position corresponding to the image of the operation button. In the example of  FIG. 4 , the operation button display section  216  displays a menu button  216 A to display a list of operations that can be selected by the user and a cross-direction button  216 B to instruct the driving mechanism  130  to move the support member  103  in the X-axis and Y-axis directions. The cross-direction button  216 B corresponds to the operation member  140 . 
     The observation apparatus control circuit  160  and image processing circuit  180  of the observation apparatus  100  and the controller control circuit  230  of the controller  200  each include an integrated circuit, such as a central processing unit (CPU), an application specific integrated circuit (ASIC) and a field programmable gate array (FPGA). Each of the observation apparatus control circuit  160 , image processing circuit  180  and controller control circuit  230  can be configured by a single integrated circuit or the like or by the combination of a plurality of integrated circuits. The observation apparatus control circuit  160  and image processing circuit  180  can be configured by a single integrated circuit or the like. 
     Each of the position control unit  161 , imaging control unit  162 , illumination control unit  163 , recording control unit  164 , communication control unit  165  and observation control unit  166  of the observation apparatus control circuit  160  can be configured by a single integrated circuit or the like or by the combination of a plurality of integrated circuits. Two or more of the position control unit  161 , imaging control unit  162 , illumination control unit  163 , recording control unit  164 , communication control unit  165  and observation control unit  166  can be configured by a single integrated circuit or the like. 
     Likewise, each of the system control unit  231 , display control unit  232 , recording control unit  233  and communication control unit  234  of the controller control circuit  230  can be configured by a single integrated circuit or the like or by the combination of a plurality of integrated circuits. Two or more of the system control unit  231 , display control unit  232 , recording control unit  233  and communication control unit  234  can be configured by a single integrated circuit or the like. 
     The operations of these integrated circuits are executed in accordance with, for example, programs stored in the observation apparatus storage circuit  170  or the controller storage circuit  240 , or the programs stored in the storage areas of the integrated circuits. 
     (Operation of Observation System) 
     The operation of the observation system  1  will be described. First, the operation of the observation apparatus  100  will be described with reference to the flowchart shown in  FIGS. 5A and 5B . The operation of the flowchart starts when the sample  300  is set in the observation apparatus  100  and then the observation apparatus  100  is held in the incubator. The flowchart corresponds to time lapse imaging, such as repeating an observation at predetermined times. 
     In step S 101 , the observation apparatus control circuit  160  determines whether the power source should be turned on. The observation apparatus control circuit  160  is configured to turn on the power source, e.g. at predetermined times. The observation apparatus control circuit  160  determines that the power source should be turned on when it is time to turn on the power source. The observation apparatus  100  constantly communicates with the controller  200  through low-power-consumption communication means such as Bluetooth Low Energy. Upon receiving an instruction to turn on the power source from the controller  200  through the communication means, the observation apparatus control circuit  160  may determine that the power source should be turned on. When the observation apparatus control circuit  160  determines that the power source should not be turned on, it repeats the process of step S 101  and thus stands by. When the observation apparatus control circuit  160  determines that the power source should be turned on, it advances the process to step S 102 . 
     In step S 102 , the observation apparatus control circuit  160  turns on the power source to supply power to the respective portions of the observation apparatus  100 . If the power source is turned on only when necessary, such as when the sample  300  is observed in practice, power saving can be attained. Particularly when the power source of the observation apparatus  100  is a battery, the advantage of lengthening the driving time of the observation apparatus  100  can be obtained. 
     In step S 103 , the observation apparatus control circuit  160  establishes communications with the controller  200 . The communication means used in this embodiment is high-speed communication means, such as Wi-Fi. 
     In step S 104 , the observation apparatus control circuit  160  determines whether setting information should be acquired from the controller  200  through the established communications. For example, when setting information is transmitted from the controller  200 , the observation apparatus control circuit  160  determines that the information should be acquired. When it determines that the setting information should not be acquired, it advances the process to step S 106 . If the observation apparatus control circuit  160  determines that the setting information should be acquired, it advances the process to step S 105 . 
     In step S 105 , the observation apparatus control circuit  160  acquires the setting information transmitted from the controller  200 . In accordance with the setting information, the circuit  160  makes settings on the respective portions of the observation apparatus  100  and performs the following process. The acquired setting information includes: information such as observation conditions including a depth of the culture medium  302  of the sample  300 , an observation mode, imaging conditions, imaging intervals, information for specifying a movement pattern, and the other parameters; a method for recording observation results; and condition information such as transmission conditions for the observation results. For example, the imaging control unit  162  adjusts the focusing position of the imaging unit  110  using information of a depth of the culture medium  302 , namely information of the thickness of an object to be observed. Furthermore, the aperture value, the exposure time, the standby time, the intensity of illumination light, etc. can properly be controlled in accordance with the imaging conditions. After that, the observation apparatus control circuit  160  advances the process to step S 106 . 
     The respective portions of the observation apparatus  100  are set in a default state according to default setting information when a first observation is started after the observation apparatus  100  is placed in the incubator. Therefore, when the process advances to step S 106  but not through step S 105 , the observation apparatus control circuit  160  performs a default process for the respective portions set in the default state. 
     In step S 106 , the observation apparatus control circuit  160  determines whether the observation apparatus is set in a manual observation mode as the observation mode. The observation mode includes a manual observation mode and an automatic observation mode. In the default state, the observation apparatus  100  is set in the manual observation mode. Since the origin of start of observation is not set when a first observation is started, the setting information transmitted from the controller  200  includes information for setting the observation apparatus  100  in the manual observation mode. It is thus assumed that the observation apparatus  100  is set in the manual observation mode when a first observation is started. When the observation apparatus control circuit  160  determines that the observation apparatus  100  is set in the manual observation mode, it advances the process to step S 107 . When the circuit  160  determines that the observation apparatus  100  is not set in the manual observation mode, namely when it determines that the observation apparatus  100  is set in the automatic observation mode, it advances the process to step S 118 . 
     In step S 107 , the observation apparatus control circuit  160  determines whether the origin position is manually designated. For example, when the operation member  140  is operated, the observation apparatus control circuit  160  determines that the origin position is manually designated. In other words, the operation member  140  functions as a position designation unit that makes it possible to designate the origin position at which a sample observation is started. Alternatively, when the controller  200  transmits designated position information in response to a user&#39;s instruction using the input device  212 , such as a touch operation of the cross-direction button  216 B of the operation button display section  216  of the display device  211  of the controller  200 , the observation apparatus communication device  150  receives the designated position information and the observation apparatus control circuit  160  determines that the origin position is manually designated. In other words, the observation apparatus communication device  150  and observation apparatus control circuit  160  each function as a position designation unit that makes it possible to designate the origin position at which a sample observation is started. When the observation apparatus control circuit  160  determines that the origin position is not manually designated, it advances the process to step S 113 . When it determines that the origin position is manually designated, it advances the process to step S 108 . 
     In step S 108 , the observation apparatus control circuit  160  turns on the light source  122  of the illumination unit  120  to emit illumination light for observation. When the illumination light has been emitted, the step S 108  can be skipped. After that, the observation apparatus control circuit  160  advances the process to step S 109 . The local area whose image is taken by the imaging unit  110  is considerably smaller than the entire region of the sample  300  as shown in  FIG. 4  as the position index  215 A, and corresponds to the illumination region of the illumination light. If, therefore, illumination light is emitted in step S 108 , a user who looks into the incubator to operate the operation member  140 , can determine a position in which the illumination light is emitted from the illumination optical system  121  or a position in which the sample  300  is irradiated with the illumination light. From the position, the user can understand the position of the imaging unit  110  disposed close to the illumination unit  120 , namely the imaging position. The user can thus operate the operation member  140  or the input device  212  of the controller  200  based on the illumination light emitting position or irradiation position to move the imaging unit  110  to a desired position in which an observation is started, namely a position close to the origin of the observation. 
     In step S 109 , the observation apparatus control circuit  160  stores the designated position in the observation apparatus storage circuit  170  as the origin position and operates the driving mechanism  130  to move the imaging unit  110  to the designated position. After that, the observation apparatus control circuit  160  advances the process to step S 110 . 
     In step S 110 , the observation apparatus control circuit  160  causes the imaging unit  110  to acquire an image at the position. After that, the observation apparatus control circuit  160  advances the process to step S 111 . 
     In step S 111 , the observation apparatus control circuit  160  corrects the imaging position information of the acquired image based on the movement direction of the imaging unit  110 . In other words, correct imaging position information is added to the acquired image based on the relationship between the last movement direction of the imaging unit  110  and the current movement direction thereof. After that, the observation apparatus control circuit  160  advances the process to step S 112 . 
     In step S 112 , the observation apparatus control circuit  160  transmits the corrected image to the controller  200  through the observation apparatus communication device  150 . After that, the observation apparatus control circuit  160  advances the process to step S 113 . 
     In step S 113 , the observation apparatus control circuit  160  determines whether an observation start is designated. For example, the observation apparatus control circuit  160  determines that an observation start is designated when an observation information transmission request is transmitted from the controller  200  in response to a user&#39;s instruction using the input device  212 , such as a touch operation of an operation button displayed on the operation button display section  216  of the display device  211  of the controller  200 . When the circuit  160  determines that an observation start is designated, it advances the process to step S 116 . When the circuit  160  determines that an observation start is not designated, it advances the process to step S 114 . 
     In step S 114 , the observation apparatus control circuit  160  determines whether the origin position designation is ended. For example, the observation apparatus control circuit  160  determines that the origin position designation is ended when the operation member  140  is operated. The observation apparatus control circuit  160  also determines that the origin position designation is ended when origin position designation end information is transmitted from the controller  200  in response to a user&#39;s instruction using the input device  212 , such as a touch operation of an operation button displayed on the operation button display section  216  of the display device  211  of the controller  200 . When the circuit  160  determines that the origin position designation is not ended, it returns the process to step S 107 . When the circuit  160  determines that the origin position designation is ended, it advances the process to step S 115 . 
     In step S 115 , the observation apparatus control circuit  160  turns off the light source  122  of the illumination unit  120  to stop emitting illumination light for observation. After that, the observation apparatus control circuit  160  advances the process to step S 128 . When the illumination light is not emitted, the step S 115  can be skipped. 
     If, therefore, the process from step S 107  to step S 114  is repeated, a user can determine a desired position at which an observation is started, namely the origin of observation to move the imaging unit  110  to the origin of observation. In other words, the image transmitted in step S 112  is displayed on the taken image display section  214  of the display device  211  of the controller  200 , and the imaging position based on the imaging position information added to the image is displayed on the imaging position display section  215  of the display device  211  as the position index  215 A. The user can thus confirm the display of the observation screen  213  of the display device  211  of the controller  200  in addition to the illumination light emitting position or irradiation position to touch the operation member  140  or the cross-direction button  216 B displayed on the display device  211  and move the imaging unit  110  to a desired position at which an observation is started, namely the origin of observation. Accordingly, the user can observe his or her favorite position (a priority observation position or the origin of observation) intensively and by priority. Since, however, this method allows an observation only in a narrow range, the observation apparatus  100  is configured to take images of respective parts in a specific sequence and observe all or part of an observation area corresponding to a movable portion within a specific range. In other words, the observation apparatus control circuit  160  (position control unit  161  and imaging control unit  162 ) is provided as a control unit and controls the operations of the driving mechanism  130  and imaging unit  110  in time sequence according to a specific rule to observe a predetermined region including at least part of the observation area from the priority observation position. 
     The X feed screw  131  and Y feed screw  133  of the driving mechanism  130  each have a backlash. For example, as shown in  FIG. 6 , there is a gap between the thread of the X feed screw  131  and the projecting portion  103 A of the support member  103  fitted to the X feed screw  131 . With this gap, the rotation directions of the feed screw, namely the last and current movement directions of the imaging unit  110  will differ from each other and thus the movement amount of the imaging unit  110  will differ from the rotation amount of the feed screw. 
     Assume that the projecting portion  103 A of the support member  103  abuts on the thread of the X feed screw  131  on the left side of  FIG. 6  when the X feed screw  131  rotates by amount N 1  as shown as state a in  FIG. 6 . Assume that from this state a, the X feed screw  131  is rotated by amount N 2  corresponding to the movement amount X 0  of the imaging unit  110  in the left direction as indicated by the arrow in  FIG. 6 . The projecting portion  103 A is thus pushed and moved immediately by the thread to move the imaging unit  110  by X n1  as shown as state b. In this case, X n1  is equal to X 0 . 
     Assume that from the state b shown in  FIG. 6 , the X feed screw  131  is rotated by amount N 1  corresponding to the movement amount X 0  of the imaging unit  110  in the right direction as indicated by the arrow in  FIG. 6 . In this state b, the projecting portion  103 A does not abut on the thread on the left side in  FIG. 6 . Therefore, even though the X feed screw  131  is rotated, the imaging unit  110  does not move at once. As shown as state c in  FIG. 6 , the imaging unit  110  starts to move after the X feed screw  131  rotates by the amount corresponding to gap Δx between the thread on the left side of  FIG. 6  and the projecting portion  103 A. Consequently, the imaging unit  110  moves by X n2  only as shown as state d in  FIG. 6 . In this case, X n2  is not equal to X 0  but to X 0 −Δx. In other words, it can be said that Δx is a movement error caused when the imaging unit  110  moves. 
     The same as above is true of the reversal of the Y feed screw  133 , namely the Y-direction movement amount of the imaging unit  110 . 
     The imaging unit  110  is moved to the origin of observation by repeating the process from step S 107  to step S 114 . If the movement direction of the imaging unit  110  is reversed, it is necessary to consider the influence of a backlash, namely the movement error Δx. In step S 111 , the imaging position information of the acquired image is corrected based on the movement direction and, in other words, correct imaging position information is added to the acquired image. The origin of observation can thus be designated correctly. When the user moves the imaging unit  110  to the priority observation position, the observation apparatus control circuit  160  may not be able to hold the correct relative positional relationship between the priority observation position and the foregoing reference position or initial position due to backlash and play of the driving mechanism  130 . This drawback can be overcome if the control for removing the backlash is performed in the priority observation position. At that time, if a taken image is recorded and the backlash removal control is performed, and then a position in which the same image is acquired in no-backlash state can be found, it will be the virtual “origin.” 
     The priority observation position may be considered to be a driving mechanism driving amount from the initial position, or an error of the drive control position of the driving mechanism  130  can be canceled, by determining a relative position by initial positioning. For example, the image detected in the priority observation position designated by the user is provisionally recorded. Once the imaging unit  110  is returned to the initial position or the reference position and then the position of an image similar to the provisionally-recorded image, the amount of relative movement of the imaging unit  110  will be position control information. If the position control information is recorded, the priority observation position will be the origin of observation. If the priority observation position is so recorded as an actuator driving amount of the initial position reference, the same place can be monitored repeatedly even after various types of drive control. The amount of relative movement of the imaging unit  110  from the initial position or the reference position can be defined as the virtual “origin.” 
     If the origin of observation is determined as described above, an observation information transmission request is transmitted from the controller  200  and thus the observation apparatus control circuit  160  determines in step S 113  that an observation start is designated and advances the process to step S 116 . 
     In step S 116 , the observation apparatus control circuit  160  turns off the light source  122  of the illumination unit  120  to stop emitting illumination light for observation. After that, the observation apparatus control circuit  160  advances the process to step S 117 . 
     In step S 117 , the observation apparatus control circuit  160  performs an observation process with correction. More specifically, the observation apparatus control circuit  160  turns on the light source  122  of the illumination unit  120  to emit illumination light for observation and instructs the imaging unit  110  and the driving mechanism  130  to cause the imaging unit  110  to take images repeatedly while changing the position of the imaging unit  110  according to a specific rule by the driving mechanism  130 . In this case, the rotation amount of the X feed screw  131  or the Y feed screw  133 , namely the driving amount of the X actuator  132  or the Y actuator  134  to move the imaging unit  110  is controlled to remove the influence of a backlash as described above, namely to correct the movement error Δx. The observation apparatus control circuit  160  performs a predetermined process for the acquired image and stores a result of observation in the observation apparatus storage circuit  170 . Upon completion of observation, the observation apparatus control circuit  160  turns off the light source  122  of the illumination unit  120  to stop emitting illumination light for observation. After that, the observation apparatus control circuit  160  advances the process to step S 122 . 
     Image acquisition according to the specific rule in the observation process of step S 117  will be described with reference to the schematic diagram of  FIG. 7 . The observation apparatus  100  takes images repeatedly while changing the position in the X direction and Y direction within, e.g. a first plane to acquire a plurality of local images  400  that are locally taken images. The image processing circuit  180  combines the local images  400  into a first whole image  401  that is one taken image in the first plane. The first plane is, for example, perpendicular to the optical axis of the imaging unit  110 , namely parallel to the transparent plate  102 . The observation apparatus  100  also takes images repeatedly while changing the imaging position to a second plane and then a third plane in the thickness direction and similarly while changing the position in the X direction and Y direction, and combines the images  400  into a second whole image  402  and a third hole image  403 . The thickness direction is a Z-axis direction corresponding to the direction of the optical axis of the imaging unit  110  and is perpendicular to the transparent plate  102 . Thus, a three-dimensional image of each portion can be acquired. 
     An example of taking images repeatedly while changing the imaging plane in the Z direction has been described. However, the image taking can be repeated while changing the position only in the X and Y directions without acquiring a plurality of images in the Z direction and, in this case, a combined image of one plane is acquired. 
     In  FIG. 7 , the whole images  401 ,  402  and  403  each include 4×4 local images  400  but actually include more local images  400 . The whole images  401 ,  402  and  403  are not limited to rectangle images. The local images  400  can be acquired such that the whole images are shaped like a polygon to conform to the circular bottom of the vessel  301 . 
     The local images  400  on each plane are acquired by moving the imaging unit  110  in a predetermined movement pattern from the determined origin of observation (X n , Y m ), as shown in  FIG. 8 . The predetermined movement pattern follows information for specifying a movement pattern included in the setting information transmitted from the controller  200 . Alternatively, it can be preset in the programs stored in the storage area in an integrated circuit to configure the observation apparatus storage circuit  170  and/or the observation apparatus control circuit  160 . For the sake of description,  FIG. 8  simply shows a movement pattern in 5×5 local images of 7×7 local images  400 . 
     When the imaging unit  110  is moved in accordance with the movement pattern, the influence of a backlash is removed or the movement error Δx is corrected to control the amount of movement so as not to vary with the movement direction of the imaging unit  110 . For example, in the example of  FIG. 8 , the rotation amount of the X feed screw  131  or the driving amount of the X actuator  132  to move the imaging unit  110  from a position in which a local image  400   2  is taken to a position in which a local image  400   3  is taken, is increased by an amount corresponding to the backlash or the movement error Δx more than the rotation amount of the X feed screw  131  or the driving amount of the X actuator  132  to move the imaging unit  110  from a position in which a local image  400   0  is taken to a position in which a local image  400   1  is taken. 
       FIG. 9  shows an exemplary configuration of data of observation results acquired as described above and stored in the observation apparatus storage circuit  170 . As shown in  FIG. 9 , observation results  500  include first data  501   1  acquired by a first observation in a manual observation mode. The observation results  500  also include second data  501   2  acquired by a second observation in an automatic observation mode described later. These data increase or decrease in number according to the number of times of observation. 
     For example, the first data  501   1  includes the following information. In other words, the first data  501   1  includes a start condition  502 . In the manual observation mode, the start condition  502  includes time at which an observation starts. In the automatic observation mode, for example, observation start time is determined in advance and thus recorded as the start condition  502 . 
     The first data  501   1  includes first local image information  503   1 , second local image information  503   2 , third local image information  503   3  and the like. Each information is a set of data acquired when one image is taken. 
     The first local image information  503   1  includes the following information. In other words, the first local image information  503   1  includes order  504 , position  505 , Z position  506 , imaging condition  507  and local image  400   0 . The order  504  is a series number for each imaging when the imaging is repeated while varying the position. The position  505  includes X and Y coordinates of the imaging position. The X and Y coordinates in the first local image information  503   1  are origin coordinates (X n , Y m ) that were determined. The X and Y coordinates are values used for control of the driving mechanism  130  and can be obtained from, e.g. the position control unit  161 . The Z position  506  includes a Z coordinate of the imaging position. The Z coordinate is a value used for control of the imaging optical system  111  and can be obtained from, e.g. the imaging control unit  162 . The imaging condition  507  includes exposure conditions such as a shutter speed and an aperture value and the other conditions. The imaging conditions may differ, depending upon each imaging operation. They may be the same for the imaging operations included in the first data  501   1 . Alternatively, they may be the same for all imaging operations included in the observation results  500 . The local image  400   0  is image data acquired by imaging. 
     Similarly, the second local image information  503   2  and the third local image information  503   3  each include information of the order, position, Z position, imaging condition and local image.  FIG. 9  shows an example of the case of the movement pattern as shown in  FIG. 8 . 
     When the imaging plane is not changed in the Z direction, information of the Z position can be omitted. 
     Like the first data  501   1 , the second data  501   2  includes a start condition, first image data, second image data, third image data and the like. 
     The observation apparatus storage circuit  170  may include all of the observation results  500  as one file and also may include some of the observation results  500  as one file. 
     Returning to  FIGS. 5A and 5B , a description will be continued. When the observation apparatus control circuit  160  determines in step S 106  that the observation apparatus is not set in the manual observation mode or it is set in the automatic observation mode, it performs the following process. More specifically, the observation apparatus control circuit  160  determines in step S 118  whether the origin of observation has already been determined, namely whether the origin position is stored in the observation apparatus storage circuit  170 . When the circuit  160  determines that the origin of observation has not yet been determined, it advances the process to step S 107  to determine the origin as in the manual observation mode. When the circuit  160  determines that the origin of observation has been determined, it advances the process to step S 119 . 
     In step S 119 , the observation apparatus control circuit  160  activates the driving mechanism  130  to move the imaging unit  110  to the origin position. The circuit  160  moves the imaging unit  110  to remove the influence of a backlash as described above, namely to correct the movement error Δx. In other words, the circuit  160  controls the rotation amount of the X feed screw  131  or the Y feed screw  133 , namely the driving amount of the X actuator  132  or the Y actuator  134  to move the imaging unit  110  to the origin position correctly. After that, the circuit  160  advances the process to step S 120 . 
     In step S 120 , the observation apparatus control circuit  160  performs the same observation process with correction as in step S 117 . More specifically, the circuit  160  turns on the light source  122  of the illumination unit  120  to emit illumination light for observation and instructs the imaging unit  110  and the driving mechanism  130  to cause the imaging unit  110  to take images repeatedly while changing the position of the imaging unit  110  according to the specific rule by the driving mechanism  130 . In this case, the rotation amount of the X feed screw  131  or the Y feed screw  133 , namely the driving amount of the X actuator  132  or the Y actuator  134  to move the imaging unit  110  is controlled to remove the influence of the backlash as described above, namely to correct the movement error Δx. The circuit  160  performs the predetermined process for the acquired image and stores a result of observation in the observation apparatus storage circuit  170 . Upon completion of observation, the circuit  160  turns off the light source  122  of the illumination unit  120  to stop emitting illumination light for observation. After that, the circuit  160  advances the process to step S 121 . 
     In step S 121 , the observation apparatus control circuit  160  determines whether the controller  200  requests observation information. For example, the controller  200  requests data acquired in the observation with correction in step S 120 . When the circuit  160  determines that the controller  200  does not request observation information, it advances the process to step S 123 . When the circuit  160  determines that the controller  200  requests observation information, it advances the process to step S 122 . 
     In step S 122 , the observation apparatus control circuit  160  transmits observation information such as the first data  501   1  and the second data  501   2  acquired by the observation with correction in step S 120  or S 117  to the controller  200  through the observation apparatus communication device  150 . The controller  200  that has received the observation information allows the observation information to be displayed on the display device  211 . After that, the circuit  160  advances the process to step S 123 . 
     In step S 123 , the observation apparatus control circuit  160  determines whether a manual position is designated by the controller  200 . There is a case where a user confirms the observation information transmitted in step S 122  by the display device  211  of the controller  200  and wishes to observe a specific position of the sample  300  again. In this case, a manual position can be designated by a user&#39;s instruction using the input device  212 , such as an operation of touching a portion corresponding to a specific position of the imaging position display section  215  of the display device  211 . When the circuit  160  determines that a manual position is not designated, it advances the process to step S 128 . When the circuit  160  determines that a manual position is designated, it advances the process to step S 124 . 
     In step S 124 , the observation apparatus control circuit  160  activates the driving mechanism  130  to move the imaging unit  110  to a manually-designated position. After that, the circuit  160  advances the process to step S 125 . 
     In step S 125 , the observation apparatus control circuit  160  causes the illumination unit  120  to emit illumination light and causes the imaging unit  110  to acquire an image in that position. After that, the circuit  160  advances the process to step S 126 . 
     In step S 126 , the observation apparatus control circuit  160  corrects the acquired image based on the movement direction of the imaging unit  110 . In other words, correct imaging position information is added to the acquired image based on the relationship between the last movement direction of the imaging unit  110  and the current movement direction thereof, in consideration of the foregoing backlash, namely the movement error Δx. After that, the circuit  160  advances the process to step S 127 . 
     In step S 127 , the observation apparatus control circuit  160  transmits the corrected image to the controller  200  through the observation apparatus communication device  150 . After that, the circuit  160  returns the process to step S 123 . 
     In step S 128 , the observation apparatus control circuit  160  determines whether the observation apparatus control process is ended. For example, when the circuit  160  receives an instruction to end the observation apparatus control process from the controller  200 , it determines that the observation apparatus control process is ended. When the circuit  160  determines that the observation apparatus control process is ended, it ends the process. For example, in a situation where a series of observations is ended and the observation apparatus  100  is taken out of the incubator, the controller  200  sends an instruction to end the observation apparatus control process and thus the observation apparatus control process is ended. Note that the setting made in step S 105  is cleared and a default value is set again, though not shown in particular. When the circuit  160  determines that the observation apparatus control process is not ended, it advances the process to step S 129 . 
     In step S 129 , the observation apparatus control circuit  160  determines whether the power source should be turned off. If standby time from the observation made in step S 117  or step S 120  to the subsequent observation is long, the circuit  160  determines that the power source should be turned off to save power consumption. Furthermore, when the circuit  160  receives an instruction to turn off the power source from the controller  200 , it determines that the power source should be turned off. When the circuit  160  determines that the power source should not be turned off, it returns the process to step S 104 . When the circuit  160  determines that the power source should be turned off, it advances the process to step S 130 . 
     In step S 130 , the observation apparatus control circuit  160  turns off the power source of each section of the observation apparatus  100 . After that, the circuit  160  returns the process to step S 101 . 
     The observation apparatus  100  makes an observation repeatedly as described above. 
     An operation of the controller  200  will be described with reference to the flowchart shown in  FIGS. 10A and 10B . The operation shown in the flowchart start when the sample  300  is placed in the observation apparatus  100  and the observation apparatus  100  is held in the incubator. 
     In step S 201 , the controller control circuit  230  determines whether an observation program according to the present embodiment is activated. Unless the observation program is activated, the circuit  230  repeats the process of step S 201 . The controller  200  is not limited to the functions of the controller of the observation system of the present embodiment but may have various functions. Therefore, when the observation program is not activated, the controller  200  may operate as a system other than the observation system  1 . If the circuit  230  determines that the observation program is activated, it advances the process to step S 202 . 
     In step S 202 , the controller control circuit  230  establishes communications with the observation apparatus  100 . This operation is related to step S 103  of the observation apparatus control performed by the observation apparatus  100 . That is, the observation apparatus  100  and the controller  200  operate such that the communications between them are established. The communications established then may be low-power-consumption communications being irrelevant to step S 103  of the observation apparatus control and only enabling the transmission of an instruction to turn on the observation apparatus  100 . 
     In step S 203 , the controller control circuit  230  determines whether the user is requesting that the observation apparatus  100  be turned on. For example, when an instruction to turn on the observation apparatus  100  is supplied through the input device  212  by, e.g. a user&#39;s touch to an operation button displayed on the operation button display section  216  of the controller  200 , the circuit  230  determines that the user is requesting that the power source be turned on. When the circuit  230  determines that the user is not requesting that the power source be turned on, it advances the process to step S 205 . The time when the user is not requesting that the power source be turned on includes a case where the power source has been turned on. When the circuit  230  determines that the user is requesting that the power source be turned on, it advances the process to step S 204 . 
     In step S 204 , the controller control circuit  230  transmits an instruction to turn on the observation apparatus  100  to the observation apparatus  100 . Subsequently, the circuit  230  advances the process to step S 205 . The operation of step S 204  is related to step S 101  of the observation apparatus control performed by the observation apparatus  100 . Upon receipt of the instruction to turn on the observation apparatus  100  from the controller  200 , the observation apparatus  100  is turned on in step S 102 . The communication means used in the embodiment are low-power-consumption communications such as Bluetooth Low Energy. 
     In step S 205 , the controller control circuit  230  determines whether a manual observation mode is requested as the observation mode in the observation apparatus  100 . For example, when an instruction to set the observation apparatus  100  in the manual observation mode is supplied through the input device  212  by, e.g. a user&#39;s touch to an operation button displayed on the operation button display section  216  of the controller  200 , the circuit  230  determines that the manual observation mode is requested. When the circuit  230  determines that the manual observation mode is not requested, or when it determines that an instruction to set the apparatus in the automatic observation mode is supplied through the input device  212 , it advances the process to step S 217 . When the circuit  230  determines that the manual observation mode is requested, it advances the process to step S 206 . 
     In step S 206 , the controller control circuit  230  sets the apparatus in the manual observation mode as the observation mode. Then, the circuit  230  advances the process to step S 207 . 
     In step S 207 , the controller control circuit  230  transmits the setting information to the observation apparatus  100 . Then, the circuit  230  advances the process to step S 208 . The operation of step S 207  is related to step S 104  of the observation apparatus control performed by the observation apparatus  100 . Upon receipt of the setting information from the controller  200 , the observation apparatus  100  sets each section in accordance with the setting information through the process of step S 105 . The setting information includes an observation mode including information for setting the observation apparatus  100  in the manual observation mode. The setting information also includes: information such as observation conditions including a depth of the culture medium  302  of the sample  300 , imaging conditions, imaging intervals, information for specifying a movement pattern, and the other parameters; a method for recording observation results; and condition information such as transmission conditions for the observation results. These items of setting information are stored in advance in the controller storage circuit  240  and can be selected by the user through the input device  212 . Alternatively, they can be set arbitrarily by the user. Since the observation apparatus  100  is set in the manual observation mode in accordance with the setting information, the observation apparatus  100  determines that the apparatus is set in the manual observation mode through the process of step S 106  and performs the process from step S 107 . 
     In step S 208 , the controller control circuit  230  determines whether the user is requesting that the manual designation of the origin position should be transmitted to the observation apparatus  100 . For example, when the circuit  230  receives a signal of a touch to the cross-direction button  216 B of the operation button display section  216  from the input device  212 , it determines that the user is requesting that the manual designation of the origin position should be transmitted. When the circuit  230  determines that the user does not request it, it advances the process to step S 213 . When the circuit  230  determines that the user is requesting it, it advances the process to step S 209 . 
     In step S 209 , the controller control circuit  230  transmits designated position information to the observation apparatus  100  to move the imaging unit  110  in a direction input by the input device  212 . Then, the circuit  230  advances the process to step S 210 . The operation of step S 209  is related to step S 107  of the observation apparatus control performed by the observation apparatus  100 . In accordance with the designated position information transmitted to the observation apparatus  100  from the controller  200 , position adjustment is made through the process of step S 109 . An image in that position is acquired by the process of step S 110  and transmitted by the process of step S 112 . 
     To designate the origin position by the input device  212 , various position designation methods can be considered in addition to the foregoing method in which the imaging unit  110  is moved to a desired origin position by repeating a touch to the cross-direction button  216 B of the operation button display section  216 . For example, as shown in  FIG. 11 , the user may designate a desired origin position directly by touching a portion corresponding to the desired origin position with his or her finger  600  on the imaging position display section  215  of the display device  211 . In accordance with the direct designation of the origin position, the position index  215 A is moved and displayed in the position of the touch and the character information  215 B indicative of the designation of the origin position is displayed. 
     In step S 210 , the controller control circuit  230  receives an image from the observation apparatus  100 . Then, the circuit  230  advances the process to step S 211 . The operation of step S 210  is related to step S 112  of the observation apparatus control performed by the observation apparatus  100 . The circuit  230  receives the corrected image which was transmitted to the controller  200  from the observation apparatus  100 . 
     In step S 211 , the controller control circuit  230  displays the received image on the taken image display section  214  of the display device  211 . Then, the circuit  230  advances the process to step S 212 . The user can confirm the displayed image to determine whether the current position of the imaging unit  110  of the observation apparatus  100  can be determined as the origin. 
     In step S 212 , the controller control circuit  230  determines whether the user is requesting that information be acquired from the observation apparatus  100 . For example, when the circuit  230  receives an instruction about information request through the input device  212 , it determines that the user is requesting information. Information to be requested is, for example, observation information about the sample  300  obtained by the observation apparatus  100 . The observation information may be included in the observation results  500  that have been described with reference to  FIG. 9 , such as image data on the sample  300 . When the circuit  230  determines that the user is requesting information, it advances the process to step S 215 . When the circuit  230  determines that the user is not requesting information, it advances the process to step S 213 . 
     In step S 213 , the controller control circuit  230  determines whether the origin position designation is ended. For example, when the circuit  230  receives a signal of a touch to the operation button displayed on the operation button display section  216  of the display device  211 , it determines that the origin position designation is ended. When the circuit  230  determines that the origin position designation is not ended, it returns the process to step S 208 . When the circuit  230  determines that the origin position designation is ended, it advances the process to step S 214 . 
     In step S 214 , the controller control circuit  230  transmits origin position designation end information to the observation apparatus  100 . Then, the circuit  230  advances the process to step S 227 . The operation of step S 214  is related to step S 114  of the observation apparatus control performed by the observation apparatus  100 . Upon receipt of the origin position designation end information from the controller  200 , the observation apparatus  100  advances the process to step S 115  by the determination in step S 114 . 
     When the controller control circuit  230  determines in step S 212  that the user is requesting that information be acquired from the observation apparatus  100 , it transmits an observation information transmission request, which is an instruction to transmit information requested by the user, to the observation apparatus  100  in step S 215 . After that, the circuit  230  advances the process to step S 216 . The operation of step S 215  is related to step S 113  of the observation apparatus control performed by the observation apparatus  100 . Upon receipt of the observation information transmission request from the controller  200 , the observation apparatus  100  performs an observation process with correction in step S 117  as described above. 
     In step S 216 , the controller control circuit  230  stands by to receive observation information, such as the first data  501   1  transmitted from the observation apparatus  100 . Upon receiving the observation information, the circuit  230  advances the process to step S 222 . The operation of step S 216  is related to step S 122  of the observation apparatus control performed by the observation apparatus  100 . Since it takes time to perform the observation process with correction in step S 117 , the circuit  230  stands by until it receives an observation result from the observation apparatus  100 . 
     When the controller control circuit  230  determines in step S 205  that the manual observation mode is not requested as the observation mode of the observation apparatus  100 , namely when it determines that an instruction to set the observation apparatus  100  in the automatic observation mode is input through the input device  212 , the circuit  230  sets the observation apparatus  100  in the automatic observation mode in step S 217 . Then, the circuit  230  advances the process to step S 218 . 
     In step S 218 , the controller control circuit  230  transmits the setting information to the observation apparatus  100 . After that, the circuit  230  advances the process to step S 219 . The operation of step S 218  is related to step S 104  of the observation apparatus control performed by the observation apparatus  100 . Upon receipt of the setting information from the controller  200 , the observation apparatus  100  sets each section in accordance with the setting information through the process of step S 105 . The setting information includes an observation mode including information for setting the observation apparatus  100  in the automatic observation mode. Since the observation apparatus  100  is set in the automatic observation mode in accordance with the setting information, the circuit  230  determines that the observation apparatus  100  is not set in the manual observation mode through the process of step S 106  and performs the process from step S 118 . 
     In step S 219 , the controller control circuit  230  determines whether the user is requesting that information be acquired from the observation apparatus  100 . For example, when the circuit  230  receives an instruction about information request through the input device  212 , it determines that the user is requesting information. Information to be requested is, for example, observation information about the sample  300  obtained by the observation apparatus  100 . The observation information may be included in the observation results  500  that have been described with reference to  FIG. 9 , such as image data on the sample  300 . When the circuit  230  determines that the user is not requesting information, it advances the process to step S 221 . When the circuit  230  determines that the user is requesting information, it advances the process to step S 220 . 
     In step S 220 , the controller control circuit  230  transmits an observation information transmission request, which is an instruction to transmit information requested by the user, to the observation apparatus  100 . Then, the circuit  230  advances the process to step S 221 . The operation of step S 220  is related to step S 121  of the observation apparatus control performed by the observation apparatus  100 . Upon receipt of the observation information transmission request from the controller  200 , the observation apparatus  100  transmits the observation information obtained by the observation process with correction in step S 120  through the process of step S 122 . 
     In step S 221 , the controller control circuit  230  determines whether it receives the observation information, such as the second data  501   2  transmitted from the observation apparatus  100 . When the circuit  230  determines that it does not receive the observation information, it advances the process to step S 223 . When the circuit  230  determines that it receives the observation information, it advances the process to step S 222 . The operation of step S 221  is related to step S 122  of the observation apparatus control performed by the observation apparatus  100  and is performed to determine whether an observation result is transmitted from the observation apparatus  100 . 
     In step S 222 , the controller control circuit  230  displays the received observation information on the display device  211  and stores it in the controller storage circuit  240 . Then, the circuit  230  advances the process to step S 223 . 
     In step S 223 , the controller control circuit  230  determines whether an instruction about manual position designation is input through the input device  212 . There is a case where the user confirms the observation information displayed in step S 222  and thus wishes to observe a specific position of the sample  300  again. In this case, a manual position can be designated by a user&#39;s instruction using the input device  212 , such as an operation of touching a portion corresponding to a specific position of the imaging position display section  215 . When the circuit  230  determines that a manual position is not designated, it advances the process to step S 227 . When the circuit  230  determines that a manual position is designated, it advances the process to step S 224 . 
     In step S 224 , the controller control circuit  230  transmits designated position information to the observation apparatus  100  to move the imaging unit  110  in a direction input by the input device  212 . Then, the circuit  230  advances the process to step S 225 . The operation of step S 224  is related to step S 123  of the observation apparatus control performed by the observation apparatus  100 . In accordance with the designated position information transmitted to the observation apparatus  100  from the controller  200 , position adjustment is made through the process of step S 124 . An image in that position is acquired by the process of step S 125  and transmitted by the process of step S 127 . 
     In step S 225 , the controller control circuit  230  receives the image from the observation apparatus  100 . Then, the circuit  230  advances the process to step S 226 . The operation of step S 225  is related to step S 127  of the observation apparatus control performed by the observation apparatus  100 . The circuit  230  receives the corrected image which was transmitted to the controller  200  from the observation apparatus  100 . 
     In step S 226 , the controller control circuit  230  displays the received image on the taken image display section  214  and stores it in the controller storage circuit  240 . Then, the circuit  230  advances the process to step S 227 . 
     In step S 227 , the controller control circuit  230  determines whether the user is requesting that the observation apparatus  100  should be turned off. For example, upon receipt of an instruction to turn off the power source of the observation apparatus  100 , the circuit  230  determines that the user is requesting that the power source should be turned off. When the circuit  230  determines that the user is not requesting that the power source should be turned off, it advances the process to step S 229 . When the circuit  230  determines that the user is requesting that the power source should be turned off, it advances the process to step S 228 . 
     In step S 228 , the controller control circuit  230  transmits an instruction to turn off the power source of the observation apparatus  100  to the observation apparatus  100 . Then, the circuit  230  advances the process to step S 229 . The operation of step S 228  is related to step S 129  of the observation apparatus control performed by the observation apparatus  100 . In accordance with the instruction to turn off the power source of the observation apparatus  100 , which is transmitted to the observation apparatus  100  from the controller  200 , the power source is turned off through the process of step S 130 . 
     In step S 229 , the controller control circuit  230  determines whether the observation program should be ended. For example, in a situation where the observation apparatus  100  is taken out of the incubator, an instruction to end the observation program is input through the input device  212 . When the circuit  230  determines that the observation program should not be ended, it returns the process to step S 203 . In other words, the foregoing operation is repeated. When the circuit  230  determines that the observation program should be ended, it advances the process to step S 230 . 
     In step S 230 , the controller control circuit  230  transmits to the observation apparatus  100  an instruction to end the observation apparatus control process in the observation apparatus  100 . After that, the circuit  230  returns the process to step S 201 . The operation of step S 230  is related to step S 128  of the observation apparatus control performed by the observation apparatus  100 . In accordance with the instruction to end the observation apparatus control process transmitted to the observation apparatus  100  from the controller, the observation apparatus  100  determines that the observation apparatus control process should be ended through the process of step S 128 . Thus, the observation apparatus control process is ended. 
     As described above, the observation in the observation system  1  can be repeated under preset conditions with preset timing from the origin position designated by the user. The observation timing and conditions are input by the user using the controller  200  and set in the observation apparatus  100 . Furthermore, the observation in the observation system  1  may be made manually each time the user instructs the observation apparatus  100  using the controller  200 . 
     (Advantage of Observation System) 
     The observation system  1  of the present embodiment can take an image of cells in the state where the sample  300  is kept stationary in the incubator. It should be noted that an image can be repeatedly taken with time. Since the origin position in which an observation is started is determined, images taken at different times can be compared with one another, with attention focused on the same portion. As a result, how the same cell or cell group changes with time can be observed by comparing the images. Even if the sample  300  is shifted in position as a result of the replacement of a culture medium, the user can designate the same origin position with the last observation timing. In the case of adhesive cells, therefore, how the same cell or cell group changes with time can be observed by comparing the images. The user can thus observe how the same cell or cell group changes with time and analyze the change. 
     The user can designate the origin position by a simple operation while watching the emitting position or irradiation position of illumination light and the taken image. The origin position can thus be determined in a short time. Therefore, no structural elements other than the imaging unit  110  and the illumination unit originally included in the observation apparatus  100  are necessary for determination of the origin position. The observation apparatus  100  can thus be simplified. 
     Furthermore, while the imaging unit  110  is moving to the origin position and while it is observing an object, it corrects an image of the object in its moving direction. It is thus possible to obtain an observation result in which the influence of a backlash of the X feed screw  131  and Y feed screw  133  is removed, namely the movement error Δx is corrected. 
     Second Embodiment 
     The second embodiment of the present invention will be described. In the description below, reference will be made to how the second embodiment differs from the first embodiment. Therefore, the same symbols will be used to denote structural elements similar or corresponding to those of the first embodiment, and a description of such structural elements will be omitted. In the observation system  1  of the first embodiment, the feed screws are used as the driving mechanism  130  to move the imaging unit  110 . In the second embodiment, a belt is used to move the imaging unit  110 . The descriptions of the first embodiment can be applied to the second embodiment unless they are inconsistent with the descriptions of the second embodiment. The devices of the first embodiment can be incorporated into the second embodiment. 
     (Configuration of Observation System) 
       FIG. 12  schematically shows a configuration of an observation system  1  according to the second embodiment. In the second embodiment, a support member  103  on which an imaging unit  110  and an illumination unit  120  are fixed, is attached to an X feed belt  135 , as shown in  FIG. 12 . The X feed belt  135  is wound on a drive roller  136  rotated by an X drive motor and a driven roller  137  provided in the C-axis direction with reference to the drive roller  136 . The X feed belt  135  is reciprocated in the X-axis direction by the rotation of the drive roller  136 . Accordingly, the imaging unit  110  fixed on the support member  103  attached to the X feed belt  135  can be moved to a desired position in the X-axis direction in accordance with a rotation direction and a rotation amount of the drive roller  136 . For the sake of brevity,  FIG. 12  does not show the X drive motor, rail guide, or the like. 
     The feed screw of the first embodiment has the problem of the influence of a backlash upon the movement of the imaging unit  110 . The belt used in the second embodiment causes the problem of the influence of extension of the belt upon the movement of the imaging unit  110 . 
     For example, as shown as state a in  FIG. 13 , assume that the X feed belt  135  is moved by movement amount X t  in the left direction as indicated by the arrow in the figure when the support member  103  is in a stationary state. In this case, the drive roller  136  is rotated to roll up a left-side belt  135 L of the X feed belt  135 , which is on the left side of the support member  103  and feed a right-side belt  135 R of the X feed belt  135 , which is on the right side of the support member  103 . At the initial stage of driving of the drive roller  136 , as shown as state b in  FIG. 13 , the left-side belt  135 L is simply pulled and extended by the drive roller  136 , and the support member  103  does not move immediately. As the drive roller  136  rotates further, the support member  103  moves abruptly to cancel the extension of the left-side belt  135 L. 
     Assume then that the drive roller  136  is stopped by the rotation amount corresponding to the movement amount X t . Even though the drive roller  136  is stopped, the support member  103  cannot be stopped immediately by the movement amount X t  due to an inertial force of the abrupt movement of the support member  103 , but moves further in the left direction in  FIG. 13 , as shown as state c in the figure. Then, the right-side belt  135 R is pulled and extended by the support member  103 . Thus, the support member  103  is pulled in the direction in which the extension of the right-side belt  135 R is canceled, and the support member  103  is pulled back in the right direction in  FIG. 13 . As a result, the support member  103  (or the imaging unit  110  fixed on the support member  103 ) is stopped in a position corresponding to a movement amount that is ΔX t  larger than a desired movement amount X t , as shown as state d in  FIG. 13 . 
     In the second embodiment, therefore, auxiliary driving  700  as shown in  FIG. 14  is performed to eliminate the influence of extension of the belt when the drive roller  136  is driven or to correct the movement error ΔX t . In  FIG. 14 , the solid line indicates an ideal movement amount in which the driving amount of the drive controller  136  is replaced with the movement amount of the imaging unit  110  and the broken line indicates the actual movement amount of the imaging unit  110 . When the drive roller  136  is driven only for time R t1  to move the support member  103  by movement amount X t , a movement error ΔX t  is caused from X t  as shown as state d in  FIG. 13 . Performing auxiliary driving  700  of moving the X feed belt  135  backward or rotating the drive roller  136  backward and then forward every predetermined time interval, the imaging unit  110  can be moved to a target position. In the auxiliary driving  700 , the drive roller  136  is driven at low speed to prevent the X feed belt  135  from extending and allow the imaging unit  110  to be positioned correctly. 
     The extension of the X feed belt  135  is the problem caused when the drive roller  136  is driven at high speed. When the imaging unit  110  is moved to the origin of observation, the drive roller  136  should be driven at high speed such that the imaging unit  110  can move a long distance in a short time. In other words, it is when correct positioning is required that the X feed belt  135  is extended. 
     In the actual observation, the movement distance is very short and thus the drive roller  136  need not be driven at so high speed. As shown in  FIG. 15 , when the drive roller  136  is drive at low speed, or when it is driven for time R t2  that is longer than time R t1  to move by the movement amount X t , no movement error is caused. Hereinafter, the low-speed driving will be referred to as response wait type driving. 
     The X feed belt  135  not only extends dynamically when the drive roller  136  is driven at high speed as described above, but also extends statically irrespective of the driving state. In other words, it is considered that the X feed belt  135  extends due to a change in temperature and with time. When the X feed belt  135  is not extended as shown in  FIG. 16A , the driving amount of the drive roller  136  necessary to move the support member  103  by a given amount in the left direction in the figure is considered to be an amount as represented by the hatched arrow in the figure. As shown in  FIG. 16B , the static extension of the X feed belt  135  is caused on both the left-side belt  135 L and right-side belt  135 R and requires a larger driving amount as represented by the hatched arrow in the figure. 
     In the second embodiment, therefore, the relationship between the current rotation amount and movement pitch of the drive roller  136  is detected when the observation is started from the origin position with each observation timing in order to correct a movement error due to a static extension of the X feed belt  135 . This relationship can be obtained by driving the drive roller  136  by a very small amount and comparing local images acquired by the imaging unit  110 . For example, when the X feed belt  135  is not extended as shown in  FIG. 16A , the drive roller  136  is controlled such that for example, adjacent two local images  400   n  and  400   n+1  in the X direction can be acquired as shown in  FIG. 17A . When the drive roller  136  is so driven, if the X feed belt  135  is extended as shown in  FIG. 16B , the acquired two local images  400   n  and  400   n+1  will overlap each other as shown in  FIG. 17B . If, therefore, the rotation amount is increased to prevent the local images from overlapping, the influence of the extension of the X feed belt  135  can be eliminated, and each of the local images  400  can be acquired in the same position with each observation timing. 
     (Operation of Observation System) 
     The operation of an observation apparatus  100  in the observation system  1  according to the second embodiment will be described below with reference to the flowchart shown in  FIGS. 18A and 18B . The operation of the flowchart starts when a sample  300  is set in the observation apparatus  100  and then the observation apparatus  100  is held in the incubator. The flowchart corresponds to time lapse imaging, such as repeating an observation at predetermined times. 
     Steps S 101  to S 108  in the flowchart are described in the foregoing first embodiment. 
     In the second embodiment, an observation apparatus control circuit  160  activates a driving mechanism  130  to move the imaging unit  110  to the designated position with auxiliary driving  700  in step S 151  in place of step S 109  of the first embodiment. Then, the observation apparatus control circuit  160  advances the process to step S 110 . 
     Steps S 110  to S 115  in the flowchart are described in the foregoing first embodiment. In the second embodiment, however, the imaging unit  110  can be moved correctly to the designated position because it is moved with auxiliary driving  700  in step S 151 . It is thus unnecessary to correct the imaging position information of the acquired image based on the movement direction as in step S 111  of the first embodiment. The process of step S 111  is thus omitted. 
     Steps S 107  to S 114  described above are repeated. Accordingly, the origin of observation can be designated correctly by auxiliary driving  700  to correct a movement error of the imaging unit  110 , caused by the extension of the X feed belt  135  due to high-speed driving of the drive roller  136  in step S 151  while the imaging unit  110  is moving to the origin of observation. 
     If the origin of observation is so determined, the observation apparatus control circuit  160  receives an observation information transmission request from a controller  200  and thus determines in step S 113  that an observation start is designated. The circuit  160  advances the process to step S 116 . 
     Step S 116  is as described in the first embodiment. 
     After that, in the second embodiment, the operations of steps S 152  and S 153  are performed in place of the operation of step S 117  in the first embodiment. 
     In step S 152 , the observation apparatus control circuit  160  instructs the driving mechanism  130  to drive the drive roller by a very small amount as described above, and compares local images acquired by the imaging unit  110  before and after the driving to detect the relationship between the rotation amount and movement pitch of the drive roller  136 . Then, the circuit  160  advances the process to step S 153 . 
     In step S 153 , the observation apparatus control circuit  160  performs a response wait type observation process. More specifically, first, the circuit  160  instructs the driving mechanism  130  to return the imaging unit  110 , which was moved for the above detection in step S 152 , to the origin position by the response wait type driving. Then, the circuit  160  turns on a light source  122  of the illumination unit  120  to emit illumination light for observation, and instructs the driving mechanism  130  to cause the imaging unit  110  to take images repeatedly while changing the position of the imaging unit  110  according to a specific rule by the response wait type driving. In this case, the rotation amount of the drive roller  136  for moving the imaging unit  110  to a desired position is controlled based on the relationship detected in step S 152  so as to remove the influence due to a static extension of the X feed belt  135 , which is caused by temperature or a lapse of time as described above, namely to correct a static movement error. The circuit  160  performs a given process for the acquired image and stores a result of the observation in an observation apparatus storage circuit  170 . Upon completion of the observation, the circuit  160  turns off the light source  122  of the illumination unit  120  to stop emitting illumination light for observation. After that, the circuit  160  advances the process to step S 122 . 
     When the observation apparatus control circuit  160  determines in step S 106  that the observation apparatus  100  is not set in the manual observation mode, or it is set in the automatic observation mode, the circuit  160  advances the process to step S 118 . Step S 118  is as described in the foregoing first embodiment. When the circuit  160  determines in step S 118  that the origin of observation has already determined, it advances the process to step S 154  in place of step S 119  of the first embodiment. 
     In step S 154 , the observation apparatus control circuit  160  activates the driving mechanism  130  to move the imaging unit  110  to the origin position. In the automatic observation mode, at least one observation has already been made, and the imaging unit  110  is not so distant from the origin position. The imaging unit  110  is thus moved to the origin position by the response wait type driving to rotate the drive roller  136  at low speed. To start the observation quickly, the imaging unit  110  can be moved by not the response wait type driving but with the auxiliary driving  700 . Then, the circuit  160  advances the process to step S 155 . 
     In step S 155 , the observation apparatus control circuit  160  determines a pitch. This operation is to detect the relationship between the rotation amount and movement pitch of the drive roller  136  by instructing the driving mechanism  130  to drive the drive roller  136  by a very small amount and comparing local images acquired by the imaging unit  110  before and after the driving, as in step S 152 . Then, the circuit  160  advances the process to step S 156 . 
     In step S 156 , the observation apparatus control circuit  160  performs a response wait type observation process as in step S 153 . More specifically, the circuit  160  first instructs the driving mechanism  130  to return the imaging unit  110 , which was moved for the pitch determination in step S 155 , to the origin position by the response wait type driving. Then, the circuit  160  turns on the light source  122  of the illumination unit  120  to emit illumination light for observation, and instructs the driving mechanism  130  to cause the imaging unit  110  to take images repeatedly while changing the position of the imaging unit  110  according to a specific rule by the response wait type driving. In this case, the rotation amount of the drive roller  136  for moving the imaging unit  110  to a desired position is controlled based on the relationship detected in step S 155  so as to remove the influence due to a static extension of the X feed belt  135 , which is caused by temperature or a lapse of time as described above, namely to correct a static movement error. The circuit  160  performs a given process for the acquired image and stores a result of the observation in the observation apparatus storage circuit  170 . Upon completion of the observation, the circuit  160  turns off the light source  122  of the illumination unit  120  to stop emitting illumination light for observation. After that, the circuit  160  advances the process to step S 121 . 
     Steps S 121  to S 123  are as described in the foregoing first embodiment. When the observation apparatus control circuit  160  determines in step S 123  that a manual position is designated by the controller  200 , it advances the process to step S 157  in place of step S 124  of the first embodiment. 
     In step S 157 , the observation apparatus control circuit  160  activates the driving mechanism  130  to move the imaging unit  110  to a manually designated position with the auxiliary driving  700 . Since the designated position corresponds to somewhere in the sample  300 , it is not so distant from the position of the imaging unit  110  at the end of the observation. The imaging unit  110  can thus be moved with not the auxiliary driving  700  but the response wait type driving. Then, the circuit  160  advances the process to step S 125 . 
     Steps S 125  to S 130  are as described in the foregoing first embodiment. In the second embodiment, however, the imaging unit  110  can be moved correctly to the designated position because it is moved with the auxiliary driving  700  in step S 157 . It is thus unnecessary to correct the imaging position information of the acquired image based on the movement direction as in step S 126  of the first embodiment. The process of step S 126  is thus omitted. 
     As has been described, the observation apparatus  100  repeats the observation in the second embodiment as well. 
     (Feature of Observation System) 
     The same advantages as described above in relation to the observation system  1  of the first embodiment can be obtained by the observation system  1  of the second embodiment as well. 
     In the second embodiment, the X feed belt  135  is used in place of the X feed screw  131  of the first embodiment. Since a dynamic movement error of the imaging unit  110  due to the extension of the X feed belt  135  at the time of high-speed driving is corrected by the auxiliary driving  700 , the imaging unit  110  can be moved correctly to the origin position. Since, furthermore, the rotation amount of the drive roller  136  is controlled so as to detect the relationship between the rotation amount and movement pitch of the drive roller  136  and correct a static movement error due to an extension of the X feed belt  135 , which is caused by a change in temperature or a lapse of time, each of the local images  400  can be acquired in the same position with each observation timing. 
     Of the techniques described in connection with the above embodiments, the controls described with reference to the flowcharts are achieved as programs. The programs can be stored in a recording medium or a storage unit. The programs can be recorded in the recording medium or storage unit in various ways. They may be recorded at the time of shipping a product, they can be recorded using a distributed recording medium, or they can be downloaded from the Internet. 
     In each of the foregoing embodiments, the top of the casing  101  of the observation apparatus  100  is covered with the transparent plate  102 , and the sample  300  is placed on the top of the casing  101 . However, the present invention is not limited to this. The shape of the observation apparatus  100  can be modified appropriately in accordance with the shape of the sample  300 , a desired observation direction, or the like. 
     In each of the foregoing embodiments, the observation apparatus  100  is simply designed to take images of a cell and the like, which are being cultured, and which records the taken images. The observation apparatus  100  may conduct different analyses, based upon the acquired image, using the observation apparatus control circuit  160  or the image processing circuit  180 . For example, the observation apparatus control circuit  160  or the image processing circuit  180  may extract images of a cell or a cell group included in the sample  300  based upon the acquired image, and calculates the number of cells or cell groups. The results of the analysis so obtained are stored in the observation apparatus storage circuit  170  or transmitted to the controller  200  through the observation apparatus communication device  150 . The observation apparatus  100  can be configured as a measurement apparatus for measurement as well as observation. Alternatively, if the controller  200  is caused to have functions of analyzing an image taken by the observation apparatus  100  of each of the embodiments to acquire the number of cells or cell groups, the form thereof, or the like, and recording the analysis results. Accordingly, a measurement system including the observation apparatus  100  can be configured. 
     Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative devices, and illustrated examples shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.