Patent Publication Number: US-2015070560-A1

Title: High speed image selecting method and digital camera having high speed image selecting function

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 13/717,453 filed Dec. 17, 2012, which is a continuation of U.S. application Ser. No. 12/533,600 filed Jul. 31, 2009, now U.S. Pat. No. 8,350,947, issued Jan. 8, 2013, which is a continuation of U.S. application Ser. No. 10/199,320, filed Jul. 22, 2002, now U.S. Pat. No. 8,237,840, issued Aug. 7, 2012, which is a divisional of U.S. application Ser. No. 09/059,330, filed Apr. 14, 1998, now U.S. Pat. No. 6,445,412, issued Sep. 3, 2002, which are incorporated by reference, herein, in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention is related to a digital camera, and more specifically, directed to a high speed image selecting method and a digital camera equipped with a high speed image selecting function, by which an enlarged thumbnail image is fed in fast-forward/fast-backward modes when an image is displayed on a display unit such as a liquid crystal display. 
     Very recently, digital cameras (electronic still image cameras) have been developed, and are commercially available, and thus are gradually popularized. 
     A digital camera is arranged as follows. Imaging (photographing) light is photoelectrically converted into image data, and this image data is recorded on a recording medium, and thereafter is outputted to an external image processing apparatus, for instance, a personal computer. Then, the image data is processed by way of a printing image data forming process in the external image processing apparatus, and then the formed printing image data is outputted to a printer, so that a photographed image is printed/reproduced on a print paper. 
     It should be noted that the most digital cameras are equipped with liquid crystal displays (LCD) for displaying photographed images and the like. On the other hand, image data acquired by photoelectric converting operation are compression-processed to be recorded on recording media. Normally, the compression process operation is carried out based on the JPEG (Joint Photographic Image Coding Experts Group) standard (will be referred to as “JPEG compression” hereinafter). 
     In the case that an image is selected on the side of a personal computer, a plurality of thumbnail images are previously acquired to be displayed on a monitor, and a user selects a desirable image. Then, the selected image data is acquired from a digital camera to be expanded, and the expanded image is displayed on the monitor. After this expanded image is confirmed by the user, this image is processed by executing a color printing image data forming process, and then this processed image is printed out by a printer connected to the personal computer. 
     A thumbnail image corresponds to a compressed image which is used when a desirable image is selected from image data acquired by a personal computer and the like. Assuming now that a data size (namely memory capacity) of image data for 1 frame is equal to 1,024×768 pixels, a thumbnail image corresponding to this 1-frame image is such a compressed image having approximately 86×60 pixels by thinning image data from this 1-frame image data. Then the thumbnail image is recorded on a recording medium of a digital camera. 
     In such a system that a digital camera is connected to a communication line and a wireless (radio) unit such as a portable telephone so as to transmit desirable image data via either a wire line or a wireless line, and/or in order to directly transmit printing image data from the digital camera to a printer to be printed out, this system should be arranged in a manner that the images are reproduced on a liquid crystal display on the side of the digital camera so as to select a desirable image. 
     However, since the image data have been JPEG-compressed to be stored in the recording medium, these JPEG-compressed image data stored in this recording medium should be read out and then be expanded, and thereafter be extended over a frame memory in order to reproduce/display the images on the liquid crystal display. 
     When expanding means for compressed data is constituted by a hardware circuit, expanding/extending process time of these compressed data may be shortened. However, in popularized digital cameras, expanding means are normally arranged in a program form (will be referred to as an “expanding program” hereinafter) so as to reduce product cost. In such popularized digital cameras, 2 to 3 seconds are necessarily required to expand a 1-frame image (1,024×768 pixels) which has been JPEG-compressed by using this expanding program. 
     As a result, there is a problem that users have such feelings that image display time would be prolonged. Moreover, when a desirable image is selected, image data must be sequentially read out to be displayed. Under such a circumstance, if a desirable image is stored in a later order, then a long time duration is actually required in order to select this desirable image. Thus, there is a further problem that such a lengthy access time is practically inconvenient. 
     SUMMARY OF THE INVENTION 
     The present invention has been made to solve the above-described problems, and therefore, has an object to provide a high speed image selecting method, and also a digital camera equipped with a high speed image selecting function, capable of enlarging a thumbnail image to feed the enlarged thumbnail image in a fast mode. 
     To achieve these and other objects, a high speed image selecting method, according to a first aspect of the present invention, is featured by such a high speed image selecting method for selecting an image photographed by a digital camera, comprising the steps of: enlarging and feeding the enlarged thumbnail images sequentially in fast-forward/fast-backward modes to be sequentially displayed; and when a desirable thumbnail image is selected from the enlarged thumbnail images under display, extending compression image data corresponding to the selected thumbnail image so as to acquire image data. 
     In this first aspect, the thumbnail image is fed in the fast-forward/fast-backward modes to be displayed in a high speed. After a desirable thumbnail image is selected, the compressed image data is expanded, so that the image can be selected in a high speed. 
     In accordance with a second aspect of the present invention, in the high speed image selecting method of the first aspect, the enlarged thumbnail images are indexed, and then the enlarged thumbnail images with the indexes are sequentially fed in the fast-forward/fast-backward modes to be sequentially displayed. 
     In this second aspect, the thumbnail images with the indexes are enlarged and the enlarged thumbnail images are fed in the fast-forward/fast-backward modes, so that the image can be further easily selected. 
     In accordance with a third aspect of the present invention, a digital camera equipped with a high speed image selecting function is featured by that in a digital camera for recording on a recording medium, image data produced by photoelectrically converting photographing light and thumbnail image data thereof, a digital camera equipped with a high speed image selecting function, comprising: a display unit for displaying an image; data expanding means for expanding compressed image data; thumbnail enlarged image display means for enlarging thumbnail image data and for displaying the enlarged thumbnail image data on the display unit; thumbnail image selecting means for feeding the enlarged thumbnail image under display in fast-forward/fast-backward modes to select a desirable thumbnail image; image display means for displaying image data corresponding to the selected thumbnail image on the display unit; and selection image defining means for defining the displayed image as a selection image. 
     In this third aspect, the thumbnail image is fed in the fast-forward/fast-backward modes to be displayed in a high speed. After a desirable thumbnail image is selected, the compressed image data is expanded, so that the image can be selected in a high speed. 
     In accordance with a fourth aspect of the present invention, a digital camera equipped with a high speed image selecting function is featured by that the fast-forward/fast-backward feeding operations of the enlarged thumbnail image by the thumbnail image selecting means are commenced by executing a predetermined switch operation. 
     In accordance with the fourth aspect, the enlarging process and the fast-forward/fast-backward feeding operations of the thumbnail image can be readily realized by a predetermined switch operation, so that the thumbnail images can be selected in a high speed. 
     A digital camera equipped with a high speed image selecting function according to a fifth aspect of the present invention, is featured by that in the digital camera equipped with the high speed image selecting function, as described in the third aspect or the fourth aspect, the fast-forward/fast-backward feeding operations of the enlarged thumbnail image by the thumbnail image selecting means are commenced when an instruction is issued such that forward/backward feeding operations of normal image data are continuously performed within a predetermined time period. 
     In accordance with the fifth aspect, when the image selection is continuously performed within a predetermined time period, the operation is automatically transferred to the enlarging operation and the fast-forward/fast-backward operations of the thumbnail image, so that the thumbnail image can be readily selected in a high speed. Also, since the enlarged thumbnail image is displayed until the image data is displayed, the waiting tension given to the user can be relaxed. 
     A digital camera equipped with a high speed image selecting function, according to a sixth aspect of the present invention, is featured by that in the digital camera equipped with the high speed image selecting function, as described in the third aspect, the fourth aspect, or the fifth aspect, the expanding process of the image data by the data expanding means is carried out in conjunction with the display process of the enlarged thumbnail image corresponding thereto. 
     According to the sixth aspect, since the enlarging/display process operation of the thumbnail image and the expanding process of the image data are carried out, the image data can be quickly displayed after the selecting operation. 
     A digital camera equipped with a high speed image selecting function, according to a seventh embodiment of the present invention, is featured by that the digital camera equipped with the high speed image selecting function, as described in any one of the preceding aspects 3 to 6, is further comprised of: indexing means for indexing the enlarged thumbnail image displayed by the thumbnail enlarged image display means. In accordance with the seventh embodiment, since the enlarged thumbnail images are indexed, the image selection by the fast-forward/fast-backward operation can be readily performed. 
     A recording medium, according to an eighth aspect of the present invention, is featured by such a recording medium readable by a digital camera for recording on the recording medium, image data produced by photoelectrically converting photographing light and also thumbnail image data thereof, on which a program is recorded and the program is capable of realizing: a data expanding function for expanding compressed image data; a thumbnail enlarged image display function for enlarging the thumbnail image data and for displaying the enlarged thumbnail image data on a display unit; a thumbnail image selecting function for feeding the enlarged thumbnail image under display in fast-forward/fast-backward modes to select a desirable thumbnail image; an image display function for displaying the expanded image data corresponding to the selected thumbnail image or the display unit; and a selection image defining function for defining the displayed image as a selection image. 
     Since the program recorded on the recording medium according to the eighth aspect of the present invention is executed, the enlarged thumbnail image can be fed in the fast-forward/fast-backward operations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1(   a ) and  1 ( b ) is a block diagram for showing a structural example of a digital camera equipped with a high speed image selecting function according to an embodiment of the present invention; 
         FIG. 2  is a block diagram for representing a structural example of high speed image selecting means; 
         FIGS. 3(   a ) and  3 ( b ) show a rear surface portion of the digital camera; 
         FIGS. 4(   a ) and  4 ( b ) are explanatory diagrams for explaining a pixel interpolation method (simple interpolation method); 
         FIG. 5  is a flow chart for describing an example of operation of the high speed image selecting means; 
         FIG. 6  is a flow chart for describing an example of operation of the high speed image selecting means; and 
         FIG. 7  is a flow chart for describing an example of operation of the high speed image selecting means. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1(   a ) and  1 ( b ) are block diagrams for representing a structural example of a digital camera according to an embodiment of the present invention. 
     In  FIG. 1(   a ), a digital camera  100  is constructed of an optical system made of a lens and a diaphragm, for entering reflection light reflected from an imaging object onto a CCD  2 ; a CCD  2  for converting the imaging light projected from the optical system  1  into an electric signal; and an image data forming unit  3  for processing the electric signal derived from the CCD  2  to be supplied as raster data (image data) of multiple values (R, G, B) to a frame memory  12 A. Furthermore, the digital camera  100  is arranged by a control unit  4 , an input means  5 , a moving picture display control unit  6 , an image data output unit  7 , a recording medium control unit  8 , a built-in recording medium  9 , an enlarged recording medium  10 , an interface  11 , an LED lamp  15  functioning as a display means, and a liquid crystal display  16 . 
     In this digital camera, the control unit  4  controls the executions of the operation controls, the image processing operations, and the image compressing/expanding process operations of the image data forming unit  3 , the moving picture display control unit  6 , the image data output unit  7 , the recording medium control unit  8 , and the high speed image selecting means  60 . The input means  5  is constituted by a button and a switch. The input means  5  inputs an instruction made by a user by manipulating these button and switch, and converts the instruction into a digital signal which will be then supplied to the control unit  4 . 
     The moving picture display control unit  6  outputs the image data to the liquid crystal display  16  so as to display the moving picture. In this embodiment, the image data stored in the frame memories  12 A and  12 B are displayed in a superimpose manner during the normal display mode. Normally, it should be noted that the image data are written into the frame memory  12 A predetermined times, for example, 30 times, or 60 times per 1 second by the image data forming unit  3 , and the image is displayed on the liquid crystal display  16  under control of the moving picture display control unit  6  in synchronism with the writing operation of the image data in the same phase. 
     In the case that a specific button is depressed while displaying a moving picture to instruct an image recording operation, the image data output unit  7  converts the R, G, B raster data saved in the frame memory  12 A into a luminance component Y, and color difference components U and V. Also, the image data output unit  7  subjects to these luminance/color difference components to the JPEG-compression, and further executes a compression process operation for producing a thumbnail image. 
     Upon receipt of the image data outputted from the image data output unit  7 , the recording medium control unit  8  controls a writing operation such that JPEG-compressed image data (simply will be referred to as “image data” hereinafter) and compressed image data are written into a predetermined position of the built-in recording medium  9 , or the enlarged recording medium  10 , and also controls a reading operation of each of the recorded JPEG image data. 
     The built-in recording medium  9  and the enlarged recording medium  10  are provided to store thereinto the image data. A serial interface, or a parallel interface  11  is employed to transmit/receive data to/from an external apparatus. Also, the LED lamp  15  displays a condition of a switch, and a functional specification. The liquid crystal display  16  displays a photographed image, or an object to be imaged. 
     Normally, the frame memory  12 A is used as an image display memory of the liquid crystal display  16 . The image data is extended in this frame memory  12 A as a bit map image. The frame memory  12 B is employed as a menu display memory, if required. Then, when an image is displayed on the liquid crystal display  16 , the storage contents of the frame memories  12 A and  12 B are displayed in a superimposed manner, if required. 
     In this embodiment, the built-in recording medium  9  is constructed of a  4  MB (Megabytes)-flash memory fixed inside the camera  100 . Not only the image data, but also other data such as a program are stored into the built-in recording medium  9 . In this embodiment, as the enlarged storage medium  10 , a 4 to 45 MB-memory card is utilized. In this case, although a memory card interface (PCMCIA interface or ATA interface: not shown) is employed, the present invention is riot limited thereto, but other card type memories such as a compact flash (a trade mark of Sun Disk Inc.) may be utilized. 
       FIG. 1(   b ) represents an arrangement of the control unit  4 . The control unit  4  is arranged by a CPU  41 , a RAM  42 , and a ROM  43 . In this ROM  43 , a program group has been previously stored, which is required to execute a data process operation within the digital camera  100 , for example, the operation control of the digital camera  100 , and the data compressing/expanding process operations. 
     Also, the digital camera  100  transmits the image data stored in the built-in recording medium  9  via the interface  11  to an external apparatus, for instance, a computer unit. The digital camera  100  communicates the image data via the modem  300 . Furthermore, in such a case that a printing image data forming process program group is saved in the digital camera  100 , printing image data is formed. Then the printing image data may be directly transmitted to a printer  400  so as to print out the image. 
       FIG. 2  is a schematic block diagram for showing a structural example of the high speed image selecting means  60  which may constitute a major portion of the digital camera according to the present invention. The high speed image selecting means  60  is constituted by a thumbnail compression image data expanding means  61 , a thumbnail image enlarging/displaying means  62 , a thumbnail image selecting means  63 , a compression image data expanding means  64 , an image display means  65 , and a selected image defining means  66 . 
     It should be understood that the high speed image selecting means  60  according to this embodiment is constituted by software. Alternatively, the high speed image selecting means  60  formed in the software may be arranged to be stored in the ROM  43 . Otherwise, the high speed image selecting means  60  recorded on an external recording medium as a software form may be acquired to be saved into the recording medium  9 . When the high speed image selecting means  60  is executed, this high speed image selecting means  60  formed in the software may be transferred to the RAM  42 . 
     The thumbnail compression image data expanding means  61  cause the thumbnail image data to be acquired into the RAM  42  so as to execute the expanding process operation of the compressed thumbnail image data, and then extends the expanded thumbnail image data into the RAM  42 . Since a pixel number of a thumbnail image is small, even when all of the thumbnail images are expanded, a total time duration to execute this expanding process thereof is extremely shorter than the expanding time of the image data. It should also be noted that in such an image process system that no compression process operation is performed to the thumbnail image data, this thumbnail compression image data expanding means  61  is no longer required. 
     The thumbnail image enlarging/displaying means  62  enlarges the expanded thumbnail image data, and transfers the enlarged thumbnail image data to the frame memory  12 A so as to extend the enlarged thumbnail image data as a picture image. Then, the thumbnail image enlarging/displaying means  62  causes either an enlarged thumbnail image  31  or an enlarged thumbnail image  35  to be displayed as an enlarged image on the liquid crystal display  16  ( FIG. 3(   a ) and  FIG. 3(   b )). 
     In this case, when a thumbnail image is simply enlarged to be displayed, intervals among adjoining pixels become coarse, so that the overall image is blurred. As a consequence, it is preferable to display such a thumbnail image produced by interpolating an enlarged image (see  FIGS. 4(   a ) and  4 ( b )). 
     When the button provided near the liquid crystal display  16  is manipulated by the user, the thumbnail image selecting means  63  judges the implication of this button manipulation, and scrolls the enlarged thumbnail image  31  or  35  within the display screen in order that a desirable image by the user is specified. 
     When the enlarged thumbnail image is displayed, the compression image data expanding means  64  acquires image data corresponding to this enlarged thumbnail image from the recording medium so as to expand this acquired image data to thereby extend the expanded image data. 
     The image display means  65  transfers the image data extended in the RAM  42  to the frame memory  12 A, and then extend this transferred image data as a picture image to thereby display this picture image on the liquid crystal display  16 . As a result, the expanding process operation of the image data is accomplished, which is specified while the enlarged thumbnail image displayed in the above-described manner is observed by the user. Then, the specified/expanded image data is overwritten into the enlarged thumbnail data, so that clear image data can be displayed. 
     When the button provided near the liquid crystal display  16  is manipulated by the user, the selected image defining means  66  judges the implication of this button manipulation, and will execute a subsequent process operation when this button manipulation instructs the definition of the selected image. 
     For the sake of an easy explanation, the thumbnail compression image data expanding means  61  is separately provided with the compression image data expanding means  64 . However, since the image data to be expanded are different from each other, both the thumbnail compression image data expanding means  61  and the compression image data expanding means  64  may be arranged to employ the same data expanding means, for example, may be arranged as a subprogram. 
     Also, the above-described high speed image selecting means  60  may be employed so as to not only select the image in the digital camera, but also select the image of the digital camera acquired by the personal computer. 
     Now, a description will be made of a pixel interpolating method that can be employed by the thumbnail image enlarging/displaying means  62 . 
     Typically, there are the linear interpolation method and the simple interpolation method ( FIGS. 4(   a ) and  4 ( b )) as a pixel interpolating method. The present invention may employ any of these interpolation methods. 
     In the linear interpolation method, a resolution conversion is carried out by performing a linear interpolation between adjoining two points, so that resolution with a predetermined level can be maintained. 
     To the contrary, the simple interpolation method is such an interpolation method that, as indicated in  FIGS. 4(   a ) and  4 ( b ), while positions of original pixels A, B, C, and D after being enlarged are calculated, assuming now that a magnification is selected to be “R” and “S” (both R and S are positive integers), the original pixels are copied (R−1) times along the X directions. After the copying operations of the original pixels along the X direction are accomplished, the original pixels are copied (S−1) times along the Y direction to fill the intervals among these original pixels. 
     In other words, as shown in  FIG. 4(   a ), while an origin is set as the original pixel “A”, if an image constituted by original pixels A(0,0), B(0,1), C(1,0), and D(1,1,) located adjacent to each other is first enlarged 4 times along the X direction, and then is enlarged 5 times along the Y direction, then positions of the original pixels A, B, C, and D after being enlarged become A(0,0), B(0,5), C(4,0) and D(4,5) (see  FIG. 4(   b )). Then, the original pixels A, B, C, and D are copied only 3 (=4−1) times along the X direction so as to fill the intervals. When the copy operations of the original pixels along the X direction are accomplished, the column is copied only 4 (=5−1) times along the Y direction. As a result of this operation, as represented in  FIG. 4(   b ), the pixels enlarged by the magnification of 4×5 are formed on the bit map. 
     In accordance with the linear interpolation method, gradation between two points may be calculated, and gradation of an enlarged image can be maintained at a certain level. As a consequence, the image quality achieved by this linear interpolation method is better than that achieved by another interpolation method. However, when the linear interpolation calculation is performed by employing a computer, a complex dividing calculation is required except for a specific case, so that a lengthy processing time period is needed. To the contrary, a processing time period by in the simple interpolation method requires the shortest time. However, since the gradation is not adjusted but also pixels are simply copied, the image quality is coarse. The larger the enlargement ratio becomes, the lower the quality of the enlarged image is rapidly decreased. Accordingly, there is a limitation that the enlargement ratio by the simple interpolation method is selected to be on the order of  4  times. 
     In accordance with this embodiment, the size of the screen of the liquid crystal display  16  employed in the digital camera  100  is limited, arid is substantially equal to a size of a thumbnail image×4 times. As a consequence, there is no problem as to the image quality. Moreover, since the interpolation speed achieved by this simple interpolation method is faster than that of another interpolation method, the enlarged thumbnail image is interpolated by employing the simple interpolation method. It should be understood that when a higher image quality of a displayed image is required, the linear interpolation method is preferably employed. 
       FIG. 5  is a flow chart for indicating an example of operations of the high speed image selecting means. It is assumed that as an initial condition, both the thumbnail image data and the image data have been subjected to the JPEG-compression and the JPEG-compressed image data have been recorded on the recording medium  9 . As indicated in  FIG. 5 , when either the button  19  or the button  20  is depressed to commence the high speed image selection, the thumbnail compression image data expanding means  61  acquires the thumbnail image data into the RAM  42 , and then expands the JPEG-compressed thumbnail image data to extend the expanded thumbnail image data into the RAM  42  (step S 1 ). Subsequently, the thumbnail image emerging/displaying means  62  sequentially gives index numbers to the expanded thumbnail image (namely, image with image number  31  in  FIG. 3(   a )), and then enlarges/interpolates the thumbnail image data with the index number (namely, simple interpolation method in this embodiment). Thus, the interpolated thumbnail image data is displayed as an enlarged thumbnail image on the liquid crystal display  16  (step S 2 ). Also, when the user depresses the button  19  or the button  20 , the high speed image selection process operation is returned to the step S 1  (step S 3 : YES). 
     While the button  20  (fast-forward button) provided near the liquid crystal display  16  is continuously depressed by the user, the thumbnail image selecting means  63  repeats the process operations defined at the steps S 1  and S 2  to successively display the thumbnail images on the liquid crystal display  16  (fast-forward) in the increment order. Conversely when this button  20  is released by the user, the display of this thumbnail image is stopped. 
     The button  19  is the fast-backward button. While this fast-backward button  19  is continuously depressed by the user, the thumbnail image selecting means  63  repeats the process operations defined at the steps S 1  and S 2  to successively display the thumbnail images on the liquid crystal display  16  (fast-backward) in the decrement order. When this button  19  is released by the user, the display of this thumbnail image is stopped. 
     When the image stop time duration has passed for a predetermined time period (2 seconds in this embodiment), it is assumed that this image is specified as the selected image. Then, the process operation is advanced to the next step S 4  (step S 3 : NO). 
     At a step S 4 , when the enlarged thumbnail image is displayed, the compression image data expanding means  64  acquires the image data corresponding to this enlarged thumbnail image from the RAM  42  to expand this acquired image data, and then extends the expanded image data into this RAM  42 . Subsequently, the image display means  65  transfers the image data extended in the RAM  42  to the frame memory i 2 A so as to be extended as the picture image. Then, the image display means  65  overwrites this extended image data on the liquid crystal display  16  (step S 5 ). 
     When either the button  17  or the button  18  is depressed by the user, the selected image defining means  66  executes the “next process” (step S 6 : YES). When either the button  19  or the button  20  is depressed by the user, the process operation is returned to the step  51  (step S 7 : YES). 
     Alternatively, in such a case that even when a predetermined time period (for example, 6 seconds) has passed, either the button  19  or the button  20  is not depressed at the step  6 , the selected image defining means  66  may be arranged to execute the “next process”. 
     It should be understood that as the “next process” after the image is selected by the high speed image selecting means  60 , there are a preparation process operation and a printing image data forming process operation. In this preparation process operation, this image data is transmitted via the wireless line, or the wire line. In this printing image data forming process operation, the printing data is formed in order to directly print out the image by the printer. These process operations may be executed by another program separately introduced into the digital camera  100 . 
       FIG. 6  is a flow chart for indicating an example of operations of the high speed image selecting means. It is assumed that as an initial condition, both the thumbnail image data and the image data have been JPEG-compressed and the JPEG-compressed image data have been recorded on the recording medium  9 . 
     In the example of  FIG. 5 , when the last-forward key button  20  and the fast-backward key button  19  are depressed, the fast-forward operation and the fast-backward operation are commenced. In this example, the normal reproducing operation is carried out at the first stage. When either the button  19  or the button  20  is continuously depressed under a predetermined condition, the operation mode is transferred to the high speed image selection mode. 
     That is, when the normal reproducing operation is carried out (step S 11 ), if either the button  19  or the button  20  is depressed (step S 12 : YES), then the compressed image data expanding means  64  acquires one preceding image data, or one succeeding image data into the RAM  42 , and expands/extends these acquired image data. Subsequently, the image display means  65  transfers the image data extended in the RAM  42  to the frame memory  12 A so as to extend this image data as a picture image which is displayed on the liquid crystal display  16  (step S 13 ). 
     In this case, if the same button is depressed at the time when the image reproducing operation is completed (step S 14 : YES), the process operation is advanced to the high speed image selection mode. The thumbnail compression image data expanding means  61  acquires thumbnail image data corresponding to one preceding image data, or the one succeeding image data into the RAM  42 , and then expands the JPEG-compressed thumbnail image data to extend the expanded thumbnail image data into the RAM  42 . Subsequently, the thumbnail image enlarging/displaying means  62  enlarges/interpolates the expanded thumbnail image data (namely, simple interpolation method in this embodiment). Thus, the interpolated thumbnail image data is displayed as an enlarged thumbnail image on the liquid crystal display  16  (step S 15 ). 
     In such a case that the button is further continuously depressed when this display of the enlarged thumbnail image is completed (step S 16 : YES), the process operation is returned to the step S 14  at which One preceding thumbnail image, or one succeeding thumbnail image is enlarged to be displayed. While the button is continuously depressed, this process operation is repeatedly carried out, so that the high speed image selection can be realized. 
     On the other hand, when depressing of the button is stopped (step S 16 : NO), the enlarged thumbnail image is displayed, the compression image data expanding means  64  acquires the image data corresponding to the thumbnail image under display from the RAM  42  to expand this acquired image data, and then extends the expanded image data into this RAM  42 . Subsequently, the image display means  65  transfers the image data extended in the RAM  42  to the frame memory  12 A so as to be extended as the picture image. Then, the image display means  65  overwrites this extended image data on the liquid crystal display  16  (step S 17 ). Then, the process operation is returned to the step S 12 . 
     While the operations of the high speed image selection process have been described, switching of the normal reproduction operation and the high speed selection reproduction operation may be executed by manipulating a predetermined switch, otherwise by any other manners. 
       FIG. 7  is a flow chart for indicating an example of operations of the high speed image selecting means. It is assumed that as an initial condition, both the thumbnail image data and the image data have been JPEG-compressed and the JPEG-compressed image data have been recorded on the recording medium  9 . 
     In the example of  FIG. 6 , when the fast-forward/fast-backward key buttons  19 / 20  are continuously depressed under a predetermined condition, the process operation is advanced to the high speed selection mode. In this example, when either the button  19 , or the button  20  is firstly depressed from the normal reproducing condition, the normal reproducing operation is carried out. The process operation is advanced to the high speed selection mode after the second process operation. 
     In other words, when the normal reproducing operation is executed (step S 21 ), a check is made as to whether or not a selection key of a menu is depressed (step S 22 ). When the selection key is not depressed (step S 22 : YES), after a menu process is executed (step S 23 ), the process operation is returned to the step S 22 . On the other hand, when the button  19 , or the button  20  is depressed (step S 24 : YES) while the selection key is not depressed (step S 22 : NO), since the first button manipulation is executed, the compressed image data expanding means  64  acquires one preceding image data, or one succeeding image data into the RAM  42 , and expands/extends these acquired image data. Subsequently, the image display means  65  transfers the image data extended in the RAM  42  to the frame memory  12 A so as to extend this image data as a picture image which is displayed on the liquid crystal display  16  (step S 25 ). 
     Next, in such a case that either the button  19  or the button  20  is not depressed for a predetermined time period, e.g., 1 second or 2 second (step S 26 : NO, step S 27 : YES), the process operation is returned to the step S 22 . Conversely, when either the button  19  or the button  20  is depressed within a predetermined time period (step S 26 : YES), since this is the second key manipulation, the process operation is advanced to the high speed image selection mode. The thumbnail compression image data expanding means  61  acquires thumbnail image data corresponding to one preceding image data, or the one succeeding image data into the RAM  42 , the thumbnail image data into the RAM  42 , and then expands the JPEG-compressed thumbnail image data to extend the expanded thumbnail image data into the RAM  42 . Subsequently, the thumbnail image enlarging/displaying means  62  enlarges/interpolates the thumbnail image data (namely, simple interpolation method in this embodiment). Thus, the interpolated thumbnail image data is displayed as an enlarged thumbnail image on the liquid crystal display  16  (step S 28 ). 
     After the display of this enlarged thumbnail image is accomplished, if the button is not depressed within a predetermined time period, for example, 1 second, or 2 seconds (step S 29 : YES), then the process operation is returned to the step S 28  at which either one preceding thumbnail image or one succeeding thumbnail image is enlarged to be displayed. When the button is continuously depressed within a predetermined time period, this process operation is repeatedly performed, so that the high speed image selection can be realized. 
     On the other hand, when the button is not depressed for predetermined time period (step S 19 : NO, step S 30 : YES), the compression image data expanding means  64  acquires the image data corresponding to this enlarged thumbnail image from the RAM  42  to expand this acquired image data, and then extends the expanded image data into this RAM  42 . Subsequently, the image display means  65  transfers the image data extended in the RAM  42  to the frame memory  12 A so as to be extended as the picture image. Then, the image display means  65  overwrites this extended image data on the liquid crystal display  16  (step S 31 ). Then, the process operation is returned to the step S 22 . 
     In  FIG. 7 , when the fast-forward/fast-backward keys are depressed after the normal image reproducing operation, the operation mode is advanced to the high speed selection mode after the second key operation. Alternatively, a predetermined flag may be set by executing the first key operation during the first process operation and the second process operation, so that the first and second process operations can be discriminated from the process operations subsequent to the second process operation. Also, the operation mode is forcibly advanced to the high speed selection mode when the second process operation is carried out. Alternatively, after the first key manipulation, when a predetermined time period (for example, 1 to 3 seconds) has passed, it may be judged that the first key manipulation is again carried out. 
     While the operations of the high speed image selection process have been described, switching of the normal reproduction operation and the high speed selection reproduction operation may be executed by manipulating a predetermined switch, otherwise by any other manners. 
     Although the various embodiments of the present invention have been described, the present invention is not limited to the above-explained embodiments, but may be modified, substituted, or changed. 
     As previously described in detail, according to the present invention, the thumbnail images are enlarged to be displayed so as to select a desirable image. While this desirable thumbnail image is displayed in the enlarge form, the image data corresponding to this thumbnail image is expand-processed, and thus the clear image can be displayed. As a consequence, even when a predetermined time duration is required to expand the JPEG-compressed image of 1 frame, the user does not have lengthy time feelings of the image display. Also, since the thumbnail image can be fed in the fast-forward/fast-backward modes, the desirable image which is recorded on the recording medium in the later order can be selected within a short time period. 
     As described above, the storage of the data captured during the taking of a photographic image may include the storing of the compressed high resolution image, and the storing of a corresponding lower resolution image. Although referred to herein as “thumbnail”, the lower resolution image need not be limited to a thumbnail, but can be a so-called screen-nail or other type of lower resolution image. For the sake of generality, any such lower resolution image referred to above using the term “thumbnail” should be understood to mean any image of lower resolution than the corresponding high resolution image that was taken in the photographic operation. 
     It will also be appreciated that the sequential showing of individual lower resolution images may be thought of as a fast display mode. It will also be understood that the showing of a display image by expanding the compressed high resolution image and displaying it may be thought of as a normal display mode.