Abstract:
The digital camera being capable of recording stereoscopic first and second still images includes an imaging device that captures the first and second still images in this order, a display unit that displays a moving image captured by the imaging device to allow framing an image to be taken. The display unit superimpose a framing assisting pattern on the moving image to facilitate the framing of the image to be taken. A grid pattern may be utilized as the framing assisting pattern. After the first still image is captured, the display unit displays the first still image, with the framing assisting pattern superimposed thereon, besides the moving image after said first still image is captured.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to a digital still camera, and in particular, to a digital still camera suitable for taking a stereoscopic pair of images. 
   A stereoscopic pair of images can be generated with a single digital camera by shooting a first still image of an object, then displacing the camera horizontally for an suitable distance, and then shooting a second still image of the same object. 
   In order to obtain a good stereoscopic effect from the pair of images taken as above, the framing of the second shoot should be adjusted to that of the first shoot. In conventional digital cameras, the framing of the image is typically performed by looking at a LCD monitor that shows a moving image currently captured by an imaging device such as a CCD. 
   The framing of the second still image, however, is difficult since the user has to remember the composition of the first still image and perform the framing of the second image by adjusting the image displayed on the LCD monitor as close as possible to that of the first image based on his/her memory. Therefore, there is a need for providing a digital camera that allows framing the second image of the stereoscopic pair of images without relying on the user&#39;s memory. 
   SUMMARY OF THE INVENTION 
   The present invention is advantageous in that a digital camera is provided that allows proper framing of the digital camera for taking a stereoscopic pair of images without relying on the user&#39;s memory. 
   According to an aspect of the invention, there is provided a digital camera for taking a stereoscopic pair of images of an object. The digital camera includes an imaging device for capturing the image of the object, a memory unit for storing a still image captured by the imaging device, and a display unit that simultaneously displays the still image stored in the memory unit, or the still image previously taken, and a moving image currently captured by the imaging device. The moving image is displayed beside the still image for allowing framing the image to be taken. 
   Since the still image previously taken is simultaneously displayed on the display unit, one can easily point the digital camera such that the object is located within the moving image at the same location as it is in the still image. By shooting the camera after framing the moving image as above, a still image can be obtained that provides a good stereoscopic effect together with the still image previously taken. 
   Optionally, the moving image and the still image are displayed side by side in a lateral direction of the display unit. Further optionally, the moving image and the still image are displayed in substantially the same size so that one can easily compare the still image and the moving image and thereby decide whether a proper framing is achieved or not. 
   In some embodiments of the invention, the display unit superimposes a framing assisting pattern on each of the moving image and the still image to facilitate the determination of the object&#39;s locations within the still image and the moving image. A grid pattern may be utilized as the framing assisting pattern that has at least one line parallel to top and bottom edges of the display unit and at least one line parallel to the side edges of the display unit. Such a grid pattern facilitates the detection of displacement and/or tilting between the objects within the two images simultaneously displayed. 
   According to another aspect of the invention, a digital camera is provided that is capable of taking stereoscopic first and second still images. The digital camera includes an imaging device that captures the first and second still images in this order, and a display unit that displays a moving image captured by the imaging device to allow framing an image to be taken. The display unit superimposes a framing assisting pattern on the moving image to facilitate the framing of the image to be taken. A grid pattern may be utilized as the framing assisting pattern. 
   After the first still image is captured, the display unit displays the first still image, with the framing assisting pattern superimposed thereon, besides the moving image. 
   In the digital camera configured as above, the framing assisting pattern is superimposed on the moving image not only during the framing of the second still image but also during the framing of the first still image. Accordingly, the user can carry out the first shoot by aiming at a distinctive part of the object with the framing assisting pattern, and then the second shoot by aiming again at the same part of the object with the same framing assisting pattern. As a result, a pair of still images providing a good stereoscopic effect can be obtained. 
   In some embodiments of the invention, the display unit has a screen which is longer in the lateral direction than in top and down direction. In such cases, two areas can be defined on the screen by dividing the screen in half along the lateral direction and the first still image is displayed on one of the two areas while the moving image is displayed on the other one of the two areas. 
   In some embodiments of the invention, the first still image is defined as a partial area of an image captured by the imaging device. In such cases, the display unit displays only an area of the moving image captured by the imaging device that corresponds to the first still image before said still image is taken. In this way, the digital camera facilitates the framing of the first still image. 
   Optionally, the digital camera has a memory device for storing the first and second still images thereinto. The first and second still images may be stored into the memory device as a single set of data for generating a picture suitable for observing a stereoscopic view by parallel view method. Alternatively, The first and second still images may be stored into the memory device as a single set of data for generating a picture suitable for observing a stereoscopic view by cross view method. 
   According to another aspect of the invention, a method for displaying images on a display unit of a digital camera is provided. The digital camera is adapted to take first and second images of an object in this order to generate a stereoscopic pair of images. The method includes displaying a moving image of the object on the display unit to allow framing an image to be taken, and additionally displaying the first still image besides the moving image after the first still image is taken. 

   
     BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS 
       FIG. 1  is a block diagram illustrating an electronic configuration of a digital camera according to an embodiment of the invention; 
       FIG. 2  illustrates a hierarchical structure of operating modes of the digital camera of  FIG. 1 ; 
       FIGS. 3A through 3C  are flow charts showing a process carried out in the digital camera of  FIG. 1 ; 
       FIGS. 4A through 4J  show exemplary images displayed on a LCD monitor of the digital camera of  FIG. 1 ; 
       FIG. 5  schematically illustrates how a first stereo image is generated; 
       FIG. 6  schematically illustrates how a set of data of a stereoscopic image to be observed by parallel view method is generated; and 
       FIG. 7  schematically illustrates how a set of data of a stereoscopic image to be observed by cross view method is generated. 
   

   DETAILED DESCRIPTION OF THE EMBODIMENTS 
   Hereinafter, an embodiment of the invention will be described with reference to the accompanying drawings. 
     FIG. 1  is a block diagram illustrating an electronic configuration of a digital camera according to the embodiment of the invention. 
   In the digital camera according to the present embodiment, a lens system  11  forms an optical image on a light receiving surface of a CCD  12  which is driven by a CCD driver  24 . The pixels of the CCD  12  convert the optical image of the object into an analog electronic signal. The analog signal is sampled by a correlation double sampling circuit (CDS circuit)  13  and then converted into digital image signal by an A/D converter  14 . Then, the digital image signal enters a microprocessor  15  which applies various processing to the image signal, such as color balancing and gamma correction, to generate digital data on the brightness and color of the image captured by the CCD  12 . 
   The microprocessor stores the obtained digital image data into a memory such as a DRAM  16 . The microprocessor  15  also saves, if required, the digital image data held in the DRAM  16  into a recording medium  26  via an interface  25 . A memory card such as a compact flash (CF) card may be utilized as the recording medium  26 . 
   The digital image data held in the DRAM  16  can be copied into a VRAM  17  to display the image on a monitor device such as an LCD monitor  22 . The digital image data copied into the VRAM  17  is converted to an analog image signal by a D/A converter  18 . Further, a video encoder  19  converts the analog image signal into a video signal and output it to an adder  20 . The adder  20  mixes a video signal generated by an on-screen display (OSD) circuit  21  to the video signal from the video encoder  19  to superimpose characters, signs, graphic images, masking patterns, grid patterns and the like on the image captured by the CCD  12 . The characters, signs and the like superimposed on the image as above may include various information on the camera such as shutter speed and f-numbers. The mixed video signal is sent to the LCD monitor  22  to display a moving image and/or a still image captured by the CCD  12 . 
   The focusing of the lens system  11  is carried out by a focusing lens driving mechanism  23 . The focusing lens driving mechanism  23  rotates a lead screw (not shown) by a pulse motor (not shown) and thereby drives a focusing lens of the lens system  11  along the optical axis thereof. The lens driving mechanism  23  is controlled by the microprocessor  15 . 
   The microprocessor  15  is connected with a main switch  27 , a mode selecting dial  28 , a selecting switch  29 , a determination switch  30 , a release switch  31 , and a photometry switch  32 . 
   The main switch  27  is for changing the state of the digital camera  10  from a sleep mode to an ON mode or vice versa. The mode selecting dial  28  is for selecting the operating mode of the digital camera  10 . In the digital camera  10  according to the present embodiment, a recording mode, a playback mode, and an edit mode can be selected by operating the mode selecting dial  28 . 
   The recording mode has several sub-modes. When the recording mode is selected by the mode selecting dial  28 , a menu for selecting the sub-mode will be displayed on the LCD monitor  22 . The sub-mode can be selected by operating the selecting switch  29  and then pressing the determination switch  30  to confirm the selection. 
   The release switch  31  and the photometry switch  32  are configured such that the photometry switch  32  becomes ON by depressing a shutter button (not shown) halfway and the release switch  31  becomes ON when the shutter button is fully depressed. When the photometry switch  32  is ON, the digital camera  10  of the present embodiment performs photometry, and when the release switch is ON, the digital camera  10  carries out a shoot. 
     FIG. 2  illustrates a hierarchical structure of the operating modes of the digital camera  10  according to the embodiment. In the digital camera  10  according to the embodiment, one of the recording mode, the playback mode, and the edit mode can be selected by operating the mode selecting dial  28 . 
   The recording mode includes several sub-modes such as program AE mode, manual mode, stereo mode, and the like. If the mode selecting dial  28  is adjusted to recording mode, the OSD circuit  21  generates a video signal to superimpose on the LCD monitor  22  one of the sub-modes of the recording mode. The sub-mode displayed on the LCD monitor  22  changes in sequence whenever the selecting switch  29  is pressed. The digital camera  10  begins to operate in the sub-mode currently displayed on the LCD monitor  22  if the determination switch  30  is pressed. 
   If the stereo mode is selected, the digital camera records two still images (which are taken one after another from two different locations so as to obtain a stereoscopic pair of images, i.e., a left image and a right image) in one frame such that the picture reproduced therefrom have one of the two still images at the left half and the other one at the right half. 
   The stereo mode has two sub-modes, i.e., parallel view mode and cross view mode. In the parallel view mode, the digital camera  10  records the stereoscopic pair of still images such that the left image becomes on the left half of the reproduced picture and the right image becomes on the right half. On the contrary, the stereoscopic pair of still images are recorded such that the left image becomes on the right half of the reproduced picture and the right image on the left half if the cross view method is selected. Note that, in the present embodiment, the still image obtained by the first shoot is defined as the left image and the still image obtained by the second shoot as the right image. 
   If the stereo mode is selected, the OSD circuit  21  generates signals for superimposing a menu on the LCD monitor  22  for selecting either the parallel view mode or the cross view mode. Selection can be carried out by operating the selecting switch  29  and then pressing the determination switch  30 . 
     FIGS. 3A through 3C  are flow charts showing a process carried out in the digital camera  10  according to the present embodiment when stereo mode is selected. 
   When the mode selecting dial  28  is set to recording mode and one of the sub-modes is selected, the digital camera  10  determines whether the stereo mode is currently selected or not (S 102 ). If the stereo mode is not selected (S 102 :NO), the process proceeds to step S 104  to operate the digital camera  10  in either the program AE mode or the manual mode, depending on the selection by the selecting switch  29 . Then, it is determined whether the main switch  27  is OFF (S 106 ). IF the main switch  27  is not OFF (S 106 :NO), the process returns to step S 102 , while the process terminates if the main switch  27  is OFF (S 106 :YES). 
   If the currently selected mode at step S 102  is the stereo mode, a menu for selecting the stereo sub-mode, i.e., either the parallel view mode or the cross view mode, is superimposed on the LCD monitor  22  (S 108 ). Note that the stereo sub-mode can be selected by operating the selecting switch  29 . 
   Then, it is determined whether the parallel view mode is selected or not (S 110 ). If the parallel view mode is currently selected (S 110 :YES), then “S 0 ” is assigned to a variable Smode (S 110 ), while “S 1 ” is assigned to the variable Smode if the currently selected mode is the cross view mode (S 110 :NO, S 112 ). 
   Next, it is determined whether the determination switch  30  is ON (S 114 ). If it is not ON (S 114 :NO), the process returns to step S 102  to repeat the steps S 102  through S 114  until the determination switch  30  is pressed. 
   If the determination switch  30  is ON at step S 114 , the process for capturing the first one of the stereoscopic pair of stills images, which will be referred to hereinafter as a first stereo image, will be carried out (steps S 116  through S 138 ). Note that, in the present embodiment, the first stereo image corresponds to the left image of the stereoscopic pair of images. 
   At step S 116 , the image currently captured by the CCD  12  is displayed on the LCD monitor  22 , as shown in  FIG. 4A , so as to allow the user to frame the object to be taken (this image will be referred hereinafter as first monitor image  40 ). 
   Next, a mark  42  such as “[]” is superimposed on the first monitor image  40  (S 118 ), as shown in  FIG. 4B . The mark  42  indicates an automatic focusing zone. That is, the digital camera  10  adjusts the focus of the lens system  11  such that the image of the object located within the mark  42  is sharply formed on the CCD  12 . 
   As shown in  FIG. 4B , the LCD monitor  22  has a landscape shape of which length to width ratio is three to four, for example. A normal picture taken by the digital camera  10  also has a landscape shape of which length to width ratio is three to four. Since the picture taken by the digital camera  10  in stereo mode includes a pair of stereo images, i.e., one stereo image on the left half of the picture and the other one stereo image on the right half, each of the stereo images has a portrait shape of which length to width ratio is three to two. 
   Since the length to width ratio differs between the LCD monitor  22  and the stereo image to be taken, it is difficult to correctly frame the stereo image if the first monitor image  40  is displayed on the LCD monitor  22  in full screen as shown in  FIGS. 4A and 4B . 
   In order to solve the problem above, a mask pattern  44  is superimposed on the first monitor image  40  as shown in  FIG. 4C  (S 120 ). The mask pattern  44  covers left and right side portions of the first monitor image  40  such that the first monitor image  40  appears only at a center area of which width is the half of the LCD monitor&#39;s width, and hence the length to width ratio of the first monitor image  40  becomes equal to that of the stereo image to be taken (i.e., three to two). 
   Next, a framing assisting pattern  46  is further superimposed on the first monitor image  40 , as shown in  FIG. 4D , to facilitate the framing of the image to be taken (S 122 ). In the present embodiment, the framing assisting pattern  46  is a grid pattern having lines parallel to the top and bottom edges of the LCD monitor  22  and lines parallel to the side edges of the LCD monitor  22 . 
   Next, it is determined whether the photometry switch  32  is ON (S 124 ). If the photometry switch  32  is not ON (S 124 :No), it is further determined whether the selecting switch  29  is ON (S 126 ). If the selecting switch is not ON (S 126 :NO), then the process returns to step S 116  to update the first monitor image  40  on the LCD monitor  22 . Thus, the process for updating the first monitor image  40  displayed on the LCD monitor  22  (S 116 –S 112 ) is repeated as long as the photometry switch  32  is not pressed and the currently selected sub-mode remains the stereo mode. Consequently, a moving image captured by the CCD  12  can be observed on the LCD monitor  22 . 
   If, at step S 126 , the state of the selecting switch  29  is ON (S 126 :YES), which indicates either of the program AE mode or the manual mode is selected, the process jumps to step S 104  to operate the digital camera  10  in the selected sub-mode. 
   If, at step S 124 , the photometry switch  32  is ON (S 124 :YES), which indicates the shutter button is depressed halfway, photometry and white balance adjustment is carries out based on the image signal from the CCD  12  (S 128 ). 
   Next, at step S 130 , automatic focusing is performed. In the present embodiment, automatic focusing is performed by the contrast detection means which is well known in the art. That is, the focusing lens of the lens system  11  is moved to a position where optimum contrast is obtained in the image formed on the CCD  12  at an area thereof corresponding to the automatic focusing zone indicated by the mark  42  superimposed on the first monitor image  40 . 
   Further, at step S 130 , the distance to the object is determined from the position of the focusing lens. The microprocessor  15  of the present embodiment includes a memory in which a lookup table is stored. The lookup table provides the relation between the focusing lens position and the object distance. The microprocessor  15  determines the object distance from the position of the focusing lens by making reference to the lookup table. The position of the focusing lens is calculated based on the number of pulses provided to a pulse motor that is equipped to the focusing lens driving mechanism  23  for driving the focusing lens. 
   At step S 132 , it is determined whether the release switch  31  is ON. In other words, it is determined whether the shutter button of the digital camera  10  is fully depressed or not. If the release switch  31  is not ON (S 132 :No), the process proceeds to step S 126 . If the release switch is ON (S 132 :Yes), an automatic exposure control is carried out (S 134 ). 
   Next, the first shoot is carried out (S 136 ). That is, a full size still image, which will be referred to hereinafter as first full size image  50 , is generated based on the output signal (image signal) of the CCD  12  and stored into the DRAM  16 . 
   At step S 138 , the first stereo image is generated from the first full size image  50 . As shown in  FIG. 5 , the first stereo image (indicated by reference number  52 ) is generated by extracting a part of the first full size image  50 . The extracted part is the center area of the first full size image  50  and the width of the extracted part is the half of that of the first full size image  50 . 
   Next, the first stereo image  52  is displayed on the LCD monitor  22  (S 140 ). Since the first stereo image  52  corresponds to the left image of a stereoscopic pair of images, as mentioned before, the first stereo image  52  is displayed on the left half of the LCD monitor  22  as shown in  FIG. 4E . 
   At step  142 , the microprocessor  15  calculates the distance for which the digital camera  10  should be laterally moved after the first shoot in order to take the second one of the stereoscopic pair of still images, which will be referred to hereinafter as a second stereo image. The amount of the lateral camera displacement depends on the object distance that is obtained at step S 130 . Generally, a good stereoscopic effect can be obtained when the digital camera  10  is moved laterally for a distance within the range of 1/30 to 1/60 of the object distance. In the present embodiment, the amount of the camera displacement is determined to be 1/40 of the object distance, which is found to be most appropriate from experiences. For example, if the object distance is 6 m, the amount of the camera displacement is determined to be 15 cm. 
   Next, the mark  42 , the mask pattern  44  and the framing assisting pattern  46  are eliminated from the LCD monitor  22 , and a guide information  54  is superimposed on the LCD monitor  22 , as shown in  FIG. 4F , for advising the user the camera location suitable for the second shoot (S 144 ). The guide information  54  includes, for example, text  54   a  indicating the direction and amount of the camera displacement, and an arrow  54   b  indicating the direction of the camera displacement. In the present embodiment, right direction is indicated by the text  54   a  and the arrow  54   b  since the second still image to be taken corresponds to the right image of the stereoscopic pair of images. Further, the guide information  54  includes text and/or a mark  54   c  that requires the user to depress the determination switch  30  to confirm that the user has seen the guide information  54 . 
   At step S 146 , it is determined whether the determination switch  30  is ON. If the determination switch  30  is not ON (S 146 :NO), it is further determined whether the selecting switch  29  is ON (S 148 ). If the selecting switch  29  is not ON (S 148 :NO), the process returns to step S 146 . If the selecting switch  29  is ON (S 148 :YES), the process jumps to step S 104 . 
   If, at step S 146 , the determination switch is ON (S 146 :YES), which indicates that the user has seen the guide information  54  displayed on the LCD monitor  22  and depressed the determination switch  30 , the process proceeds to step S 150  to start the operation for shooting the second stereo image (steps S 150 –S 164 ). 
   That is, at step  150 , the guiding information  54  is removed from the LCD monitor  22 . 
   Then, a second monitor image  56  is displayed on the right half of the LCD monitor  22 , as shown in  FIG. 4G , so as to allow the user to frame the digital camera  10  for the second shoot (S 152 ). Namely, a center part of an image currently captured by the CCD  12  is extracted to get an image of half size in width direction, and displayed on the right half of the LCD monitor  22 . 
   At step S 154 , framing assisting patterns  60  and  62  are superimposed on the first stereo image  52  and the second monitor image  56 , respectively, as shown in  FIG. 4H . A line thicker than the lines of the framing assisting patterns  60 ,  62  is also displayed on the boundary between the first stereo image  52  and the second monitor image  56 . 
   The framing assisting patterns  60  and  62  have the same arrangement as that of the frame assisting pattern  46  superimposed on the first monitor image  40  at step S 122 . The framing assisting patterns  60  and  62  facilitates the framing of the digital camera  10  so as to locate the object in the second monitor image  56  at substantially the same location as that in the first stereo image  52 . 
   At step S 156 , a guide information  64  is super imposed on the first stereo image  52  as shown in  FIG. 4I . The guide information  64  includes text indicating the amount of camera displacement calculated at step S 142  as well as a mark indicating the direction of displacement. 
   Next, it is determined whether the release switch  31  is ON (S 158 ). In other words, it is determined whether the shutter button is fully depressed. If the release switch  31  is not ON (S 158 :NO), then it is determined whether the selecting switch  29  is ON (S 160 ). If the selecting switch  29  is ON (S 160 :YES), the process jumps to step S 104 . The process, however, returns to step S 150  to repeat the steps S 150  through S 156  if the selecting switch  29  is not ON (S 160 :NO). In the later case, the monitor image displayed on right half of the LCD monitor  22  is updated by repeating the step S 152  and thereby a moving image captured by the CCD  12  can be observed on the LCD monitor  22 . 
   If, at step S 158 , the release switch  31  is ON (S 158 :YES), the exposure of the digital camera  100  is adjusted to the same condition as that of the first shoot (S 162 ). 
   At step S 164 , the second shoot is carried out. That is, a full size still image, which will be referred to hereinafter as a second full size image, is generated based on the output signal (image signal) of the CCD  12  and stored into the DRAM  16 . It should be noted that the shooting conditions (i.e. focusing distance, exposure condition, object distance, condition of white balance etc) is kept the same between the first and second shoots except for the location of the digital camera  10 . Accordingly, the automatic focusing, for example, is not performed for the second shoot to keep the focusing lens of the lens system  11  at the position where it was at the time of the first shoot. 
   At step S 166 , the second stereo image is generated from the second full size image in a manner similar to generating the first stereo image  52 . That is, the second stereo image is generated by extracting a center part of the second full size image of which width is half of the full size image. 
   The second stereo image corresponds to the right image of a stereoscopic pair of images. Accordingly, at step S 168 , the second stereo image obtained as above is displayed on the right half of the LCD monitor  22  as shown in  FIG. 4J  (see reference number  66 ). 
   Next, it is determined whether the variable Smode is “S 0 ” (S 170 ). In other words, it is determined whether the parallel view mode is currently selected. If the variable Smode is “S 0 ” (S 170 :Yes), a set of data for a stereoscopic image  70  which is to be observed by parallel view method is generated from the first and second stereo images  52 ,  66  (S 172 ) , as schematically illustrated in  FIG. 6 , and stored into the DRAM  16 . That is, an image is generated of which left half is the first stereo image  52  and the right half is the second stereo image  66 . 
   If, at step S 170 , the variable Smode is not “S 0 ”, a set of data for an stereoscopic image  72  which is to be observed by cross view method is generated from the first and second stereo images  52 ,  66 , as schematically illustrated in  FIG. 7 , and stored into the DRAM  16  (S 174 ). Namely, in the cross view stereoscopic image  72 , the first stereo image  52  is located on the right half and the second stereo image  66  on the left half as shown in  FIG. 7 . 
   Next, the stereoscopic image  70  for parallel view method or the stereoscopic image  72  for cross view method is compressed (S 176 ) and then stored into the CF card  26  (S 178 ). 
   Next, an inquiry is displayed on the LCD monitor  22  asking the user whether to continue the stereo mode or not (S 180 ). Then, it is determined whether the determining switch  30  is ON or depressed (S 182 ). If the determining switch  30  is ON (S 182 :YES), the process returns to step S 116  to take the next stereoscopic pair of images. If the determining switch  30  is not ON (S 182 :NO), then it is determined whether the selecting switch  29  is ON or not (S 184 ). If the selecting switch  29  in not ON (S 184 :NO), then the process returns to step S 180 . If, however, the selecting switch  29  is ON (S 184 :YES), which indicates either the program AE mode or the manual mode is selected instead of the stereo mode, then the process jumps to step S 104 . 
   The process shown in  FIGS. 3A through 3C  terminates when the main switch  27  is turned off or when the mode selecting dial  28  is adjusted to a mode other than recording mode. 
   As described above, in the digital camera  10  according to the embodiment of the invention, the first stereo image  52  and the second monitor image  56  are displayed on the LCD monitor  22  side by side. Thus, framing of the second image to be taken can be carried out with referring to the composition of the first stereo image  52 . It should be noted that the framing can be easily carried out since the framing assisting pattern ( 60 ,  62 ) is superimposed on both of the first stereo image  52  and the second monitor image  56 . 
   It should be also noted that the framing assisting patterns ( 60 ,  62 ) facilitate the detection of the positional difference in up and down direction or tilt between first stereo image  52  and the second monitor image  56  since a grid pattern is used as the framing assisting pattern ( 60 ,  62 ) that consists of lines extended in up and down direction and lateral direction of the LCD monitor  22 . 
   Further, since the framing assisting pattern is also superimposed on the first monitor image  40 , the user can aim at a distinctive part of the object with the framing assisting pattern when the first stereo image is to be taken. Then, the user can easily adjust the framing of the second shoot to the composition of the first stereo image by aiming at the same distinctive part of the object with the framing assisting pattern when the second stereo image is to be taken. 
   It should be noted that although a gird pattern is utilized as the framing assisting pattern in the embodiment describe above, other pattern such as a cross superimposed on the image at the center thereof or an array of a plurality of small crosses or dots may also be utilized as the framing assisting pattern. 
   The present disclosure relates to the subject matter contained in Japanese Patent Application No. P2002-035013, filed on Feb. 13, 2002, which is expressly incorporated herein by reference in its entirety.