Abstract:
A portable information terminal and an image management program are provided. A portable information terminal includes: a display part which has a screen capable of displaying at least an image; an in-focus value computing part which computes an in-focus value from an original image; an image cutting part which cuts a thumbnail image from the original image based on the in-focus value computed at the in-focus value computing part; a data storage part which stores data of the thumbnail image cut at the image cutting part; and a control part which reads the data of the thumbnail image stored in the data storage part as necessary and displays it on a screen of the display part.

Description:
CROSS REFERENCES TO RELATED APPLICATIONS  
       [0001]     The present invention contains subject matter related to Japanese Patent Application JP 2005-278724 filed in the Japanese Patent Office on Sep. 26, 2005, the entire contents of which being incorporated herein by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a portable information terminal which can show an image list on a display device mounted thereon, and an image management program which creates a thumbnail image from an original image and displays it in a list.  
         [0004]     2. Description of the Related Art  
         [0005]     In an image list representation application before, a taken image or an image stored in a storage is scaled down as it, and is formed in a thumbnail image, and thumbnail images are listed and displayed on the screen of a display device.  
         [0006]     In addition, in the case in which thumbnail images are listed and displayed on the screen of a display device mounted on a cellular telephone terminal, the size and resolution of thumbnail images are also scaled down in accordance with the screen size and resolution of the display device, and thus the images are really difficult to see.  
         [0007]     Here, in Publication of unexamined patent application JP-A-2000-224465 (Patent Reference 1), a technique is disclosed in which a digital still camera is provided with a sight line detecting part which detects the convergent point of sight of a user, the essential area in a taken image is specified based on information about the convergent point of sight of the user detected by the sight line detecting part, that is, it is made possible to specify which area in the taken image the photographer focuses on, and such a process is performed that the resolution is increased or the compression ratio is reduced with respect to the image of the essential area, whereby an image easy to see can be created on which the photographer&#39;s intention is reflected.  
         [0008]     In addition, in Publication of unexamined patent application JP-A-2004-328283 (Patent Reference 2), a technique is disclosed in which a portion is calculated that a focal point is obtained in an image, the compression ratio of the portion at which the focal point is obtained is more reduced than the compression ratio of the other portions, whereby the deterioration of image quality is decreased, which is caused by scaling down an original image.  
         [0009]     Patent Reference 1: JP-A-2000-224465 (FIGS. 1, 2 and 5)  
         [0010]     Patent Reference 2: JP-A-2004-328283 (FIGS. 1 and 2)  
       SUMMARY OF THE INVENTION  
       [0011]     However, it is difficult to adapt the technique described in the Publication of unexamined patent application JP-A-2000-224465 to a cellular telephone terminal, for example. More specifically, for example, in the technique described in the publication, the construction of the sight line detecting part. is necessary which detects the convergent point of sight of the user, and it is difficult to mount such the construction on the cellular telephone terminal. In addition, even though the technique described in the publication is adapted to improve the image quality of the essential area on which the photographer focuses on, images listed on a small screen of a display device mounted on the cellular telephone terminal are not made easy to see so much. In addition to this, for example, since the convergent point of sight is unknown in the case of an image obtained from outside, the essential area itself cannot be specified.  
         [0012]     Similarly, also in the case in which the technique described in the Publication of unexamined patent application JP-A-2004-328283 is adapted to the cellular telephone terminal, for example, it is difficult to make images easy to see that are listed on the screen of the display device of the cellular telephone terminal. More specifically, the technique described in the publication can suppress the deterioration of image quality in scaling down the original image but it cannot make images easy to see so much that are listed on a small screen of the display device mounted on the cellular telephone terminal.  
         [0013]     It is desirable to provide a portable information terminal and an image management program which allow images to be made easy to see that are listed on the screen of a display device such as a display device mounted on a cellular telephone terminal that the screen size is small and the resolution is not so high.  
         [0014]     A portable information terminal according to an embodiment of the invention solves the problems by providing a portable information terminal including: a display part which has a screen capable of displaying at least an image; an in-focus value computing part which computes an in-focus value from an original image; an image cutting part which cuts a thumbnail image from the original image based on the in-focus value computed at the in-focus value computing part; a data storage part which stores data of the thumbnail image cut at the image cutting part; and a control part which reads the data of the thumbnail image stored in the data storage part as necessary and displays it on a screen of the display part.  
         [0015]     In addition, an image management program according to an embodiment of the invention solves the problems by providing an image management program which allows a portable information terminal to function as: an in-focus value computing part which computes an in-focus value from an original image; an image cutting part which cuts a thumbnail image from the original image based on the in-focus value computed at the in-focus value computing part.; a storage control part which stores data of the thumbnail image cut out at the image cutting part in a data storage part; and a display control part which reads the data of the thumbnail image stored in the data storage part as necessary and displays it on a screen of a display part.  
         [0016]     More specifically, the in-focus area in the original image is highly likely to be a target for shooting when an image is taken, and is the characteristic portion in the original image. In an embodiment of the invention, the in-focus area (the characteristic portion in the original image) is cut out of the original image as a thumbnail image. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  shows a diagram depicting an application stack of a cellular telephone terminal according to an embodiment of the invention;  
         [0018]      FIG. 2  shows a diagram depicting an exemplary taken original image;  
         [0019]      FIG. 3  shows a diagram depicting a state that an original image is divided into a plurality of equal areas and an exemplary thumbnail image cut out of the original image;  
         [0020]      FIG. 4  shows a diagram depicting an exemplary three-dimensional in-focus value distribution obtained from in-focus computation according to a modified Laplacian method;  
         [0021]      FIG. 5  shows a diagram depicting an exemplary thumbnail image cut out of the original image;  
         [0022]      FIG. 6  shows a flow chart depicting the flow of a thumbnail image creating process according to the embodiment; and  
         [0023]      FIG. 7  shows a block diagram schematically depicting the internal configuration of the essential part of the cellular telephone terminal according to the embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0024]     Hereinafter, an embodiment of a portable information terminal and an image management program will be described with reference to the drawings.  
         [0025]     In addition, in the embodiment, a cellular telephone terminal is taken as an exemplary portable information terminal according to an embodiment of the invention. However, of course, the descriptions explained here are only examples, and it is without saying that the invention is not limited to these examples.  
         [0026]     A cellular telephone terminal according to the embodiment is a terminal installed with a camera function, and the camera function provides a function that detects the area in which a focal point is obtained (hereinafter, denoted as an in-focus area) for a taken image or an image obtained from outside, cuts the in-focus area thereof out of an original image, and creates a thumbnail image from the cut in-focus area.  
         [0000]     Application Stack  
         [0027]      FIG. 1  shows an application stack of the cellular telephone terminal according to the embodiment.  
         [0028]     In  FIG. 1 , the cellular telephone terminal according to the embodiment has a camera application  10  and a viewer application  11  as an application layer.  
         [0029]     The camera application  10  is the application that uses the camera function provided in the cellular telephone terminal to shoot an image. The camera application  10  is executed to take image data, and the taken image data is stored as an original image  14  in a data storage  13  for image data through an image managing part  12  of a middleware. In addition, the data storage  13  is configured to allow storing the image taken by the camera function as well as storing an image obtained from outside, for example, as the original image  14 .  
         [0030]     The viewer application  11  is the application that executes a browsing process in which the image taken by the camera application  10 , the image obtained from outside, and the thumbnail image created by the image managing part  12 , described later, are displayed on the screen of a display device provided in the cellular telephone terminal according to the embodiment.  
         [0031]     The image managing part  12  exists in the middleware layer, which is the software that runs the image management program according to an embodiment of the invention in which in storing the original image  14  taken by the camera function and the original image  14  obtained from outside in the data storage  13 , as described later, the in-focus area is detected based on the data of the original image  14  as well as the in-focus area is cut out to create a thumbnail image  15  from the cut in-focus area. Subsequently, the image managing part  12  stores the thumbnail image  14  in the data storage  13 .  
         [0032]     In addition, for example, when the viewer application  11  requests to read the thumbnail image, the image managing part  12  reads the thumbnail image  14  stored in the data storage  13 , and supplies it to the viewer application  11 . Thus, on the screen of the display device mounted on the cellular telephone terminal according to the embodiment, the thumbnail image  14  is listed.  
         [0000]     Thumbnail Image Creating Process  
         [0033]     Hereinafter, a thumbnail image creating process performed in the image managing part  12  will be described.  
         [0034]     The camera function of the cellular telephone terminal according to the embodiment has a focus control mechanism. Suppose that the focus control mechanism obtains the focal point, and then an original image  20  is taken as shown in  FIG. 2 , for example. In addition, suppose that among some of subject images  21  to  23  (hereinafter, they are referred to as objects  21  to  23 ) shown in the original image  20 , the target subject that a photographer intends to shoot, that is, the subject on which the focal point is obtained by the focus control mechanism is the object  21 . The other objects  22  and  23  are images out of focus as compared with the object  21  which the focal point is obtained for shooting.  
         [0035]     In this case, as shown in  FIG. 3 , the image managing part  12  according to the embodiment divides the original image  20  into a plurality of equal areas  28 , and performs predetermined in-focus computation for each of the areas  28  to compute the area in which the focal point is obtained. For the scheme of in-focus computation, there are various schemes. In the embodiment, a modified Laplacian method is used which is a typical scheme thereof. More specifically, the modified Laplacian method is the scheme in which the focused pixel is expressed by 1 (x, y) to perform computation as expressed by Equation (1), whereby an in-focus value is determined.  
               Equation   ⁢           ⁢   1     ⁢     
     ⁢           ⁢           Δ   ⁢             M   2     ⁢     I   ⁡     (     x   ,   y     )         =                δ   2     ⁢   I       δ   ⁢           ⁢     x   2              +              δ   2     ⁢   I       δ   ⁢           ⁢     y   2                          (   1   )             
 
         [0036]     Of course, in the embodiment of the invention, methods other than the modified Laplacian method may be used.  
         [0037]     Here, suppose that as the result of in-focus computation according to the modified Laplacian method for each of the areas  28  of the original image  20  shown in  FIG. 3 , for example, a three-dimensional in-focus value distribution is obtained as shown in  FIG. 4 . More specifically, from the original image  20  shown in  FIG. 3 , such a in-focus value distribution is obtained that the in-focus value is great in the area including the object  21  that the focal point is obtained for shooting whereas the in-focus value is small in the other areas.  
         [0038]     Subsequently, the image managing part  12  compares the in-focus value for each of the areas  28  with a predetermined threshold based on the in-focus value distribution as shown in  FIG. 4 , and determines only the area in which the in-focus value exceeds the threshold as the in-focus area as well as it cuts the image in a predetermined size including the determined in-focus areas as the thumbnail image. Alternatively, it detects the area having the maximum in-focus value as the in-focus area among the individual areas  28 , and cuts the image in a predetermined size including the detected in-focus area as the thumbnail image. More specifically, in the case of the example shown in  FIG. 3 , the image managing part  12  cuts the image formed of the area (for example, 4×4 area) in a predetermined size including the focused object  21  as a thumbnail image  29  as shown in  FIG. 5 .  
         [0039]     In addition, when the in-focus value distribution above is determined, it may be considered that in the original image, there is a plurality of in-focus areas having almost equal in-focus values dispersedly. In this case, for example, the image managing part  12  is allowed to perform a proper process in accordance with the descriptions of the original image  20  in such a way that it cuts the image in a predetermined size including a closer in-focus area at the center of the original image as a thumbnail image among a plurality of in-focus areas having almost equal in-focus values, or cuts the image in a predetermined size containing some in-focus areas as a thumbnail image among a plurality of in-focus areas having almost equal in-focus values.  
         [0000]     Flow Chart of the Thumbnail Image Creating Process  
         [0040]      FIG. 6  shows a flow chart depicting the thumbnail image creating process performed at the image managing part  12 .  
         [0041]     In  FIG. 6 , when a shooting function is executed by the camera application  10 , for example, at Step S 10 , and the data of the original image is inputted from the camera application  10  at Step S 11 , the image managing part  12  divides the original image  20  into a plurality of equal areas  28  in accordance with the image size as the process step at Step S 12 , as shown in  FIG. 3  described above.  
         [0042]     Subsequently, as the process step at Step S 13 , the image managing part  12  performs in-focus computation for each of the areas  28  according to the modified Laplacian method expressed by the Equation (1), and as the process step at Step S 14 , it computes the in-focus area according to a comparison process with a predetermined threshold or a detecting process of the maximum in-focus value, as described above.  
         [0043]     Subsequently, as the process step at Step S 15 , the image managing part  12  cuts the image in a predetermined size including the in-focus area determined in the process step at Step S 14 , and as the process step at Step S 16 , it then sets the cut image as the thumbnail image  29 .  
         [0044]     After that, the image managing part  12  stores the thumbnail image  29  in the data storage.  
         [0000]     Internal Configuration of the Cellular Telephone Terminal  
         [0045]      FIG. 7  shows the schematic internal configuration of the cellular telephone terminal according to the embodiment having the camera function and the thumbnail image creating function, as described above.  
         [0046]     In  FIG. 7 , a data line is a transmission line which transmits various items of data such as sound data, e-mail data and image data.  
         [0047]     A control line is a transmission line which transmits various items of control information such as control data from a control part  30  which is configured of a CPU (central processing unit).  
         [0048]     An antenna  32  is an antenna built in the cellular telephone terminal according to the embodiment, which is connected to a communication circuit  31  for use in sending and receiving signal waves.  
         [0049]     The communication circuit  31  converts, modulates and demodulates the frequency of sent and received signals.  
         [0050]     Here, the sound data of a call received at the antenna  32  and the communication circuit  31  is sent to a speech processing part  42 , and the other received data is sent to the control part  30  and processed properly, and then sent to each part from the control part  30  as necessary. In addition, the received data other than the sounds of a call is the data of packet transmission. For example, the flowing data is named such as e-mail data, image data such as moving images and still images, music data, HTML (Hyper Text Markup Language) data, data of program codes, etc.  
         [0051]     When the antenna  32  and the communication circuit  31  supply the sound data of a call, the speech processing part  42  decodes the sound data of the call, converts the decoded sound data of the call to an analog sound signal, and sends the analog sound signal to a speaker  40  or to an earphone jack, not shown.  
         [0052]     The speaker  40  is built in the cellular telephone terminal according to the embodiment, which amplifies the supplied analog sound signal by an internal amplifier, converts the sound signal to audible sounds, and then outputs them outside. Thus, the speaker  40  is to output the sounds of the call.  
         [0053]     A microphone  41  is built in the embodiment the cellular telephone terminal, which converts input sounds to an analog sound signal as well as amplifies it by the internal amplifier, and sends the analog sound signal to the speech processing part  42 .  
         [0054]     When the microphone  41  supplies the sound signal of the call, the speech processing part  42  converts the sound signal if the call to digital sound data and then encodes it, and sends the encoded sound data of the call to the communication circuit  31 . Thus, the antenna  32  is to send the sound signal of the call.  
         [0055]     A display part  33  is a display device of the cellular telephone terminal according to the embodiment, which has a display such as a liquid crystal display and a display drive circuit to display images and characters on the screen of the display.  
         [0056]     An operating part  34  is formed of a numeric keypad, various buttons -and an operation signal generator which generates an operation signal when the keys and buttons are operated.  
         [0057]     A camera part  44  corresponds to the camera function provided in the cellular telephone terminal according to the embodiment, which creates data of a still image and a moving image obtained by converting a light figure to an electric signal by an imaging device, and sends it to an image processing part  43 .  
         [0058]     Under control of the control part  30 , the image processing part  43  compresses and encodes the image taken at the camera part  44 , performs the thumbnail image creating process, stores image data in the data storage  45 , performs decompression and decoding processes for the compressed and encoded image data read out of a data storage  45  or a memory part  35 . The image after decompressed and decoded and the data of the thumbnail image are to be sent to the display part  33  through the data line for display. In addition, the control part  30  may perform the thumbnail image creating process.  
         [0059]     The memory part  35  includes a RAM (Read Only Memory) and a RAM (Random Access Memory). The ROM stores an OS (Operating System), a control program that the control part  30  controls each part and program codes for performing various functions, image management program codes that the image processing part  43  or the control part  30  performs the thumbnail image creating process, various default values, font data, dictionary data, an incoming call melody and key operating sounds according to the embodiment, various sound data for alarm sounds, program codes for the camera application  10  according to the embodiment, program codes for the viewer application  11 , program codes for applications to create and edit e-mail, and program codes for applications to perform various processes for images and sounds, in addition to these, program codes for various applications mounted on the cellular telephone terminal, and identification information (ID) for the cellular telephone terminal, etc. The ROM includes rewritable ROM such as a NAND-type flash memory) or EEPROM (Electrically Erasable Programmable Read-Only Memory), which can store e-mail data, data of telephone book and an e-mail address book, still image data and moving image data (video click data, etc.), key operating sounds, sound data for alarm sounds, character data and registration data for candidate words of predictive conversion and learning data for predictive conversion, in addition to these, various user set values, etc. The RAM stores data at anytime as the working area when the control part  30  processes various data.  
         [0060]     The data storage  45  is the storage for image data described in  FIG. 1 . In addition, the data storage  45  may be included in the memory part  35 .  
         [0061]     The control part  30  is formed of the CPU, which performs control over the cellular telephone terminal, control for implementing various functions according to the embodiment and various computation based on the OS and various programs stored in the memory part  35 .  
         [0062]     In addition to this, not shown in  FIG. 7 , the cellular telephone terminal according to the embodiment of course has various functions provided on a classic cellular telephone terminal such as a GPS (Global Positioning System) function, a near wireless communication function, a noncontact communication function, a battery, etc.  
         [0000]     Conclusion  
         [0063]     As described above, according to the cellular telephone terminal according to the embodiment of the invention, the in-focus area including the target object that a photographer intends to shoot-is cut out of the original image taken by the camera function and the original image obtained from outside, and a thumbnail image can be created. Since the thumbnail image is the image that is characteristic portion in the original image, thumbnail images can be listed that are easy to see with high browsing and visual recognition properties even on a display device that has a small screen size and relatively low resolution.  
         [0064]     In addition, the description of the embodiment is an example of the invention. Therefore, the invention is not limited to the embodiment, which can be of course modified variously depending on design, for example, without deviating from the teachings of the technical principles of the invention.  
         [0065]     The thumbnail image process according to the embodiment is not limited to the image taken by the cellular telephone terminal, which can be adapted to the image taken by other devices, and can be used for general purposes.  
         [0066]     It should be understood by those skilled in the art that various modifications combinations, sub-combinations and alterations may occur depending on design requirements and other factors insofar as they are within the scope of the appended claims or the equivalents thereof.