JP2006270752A - Electronic finder and electronic camera using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic camera capable of attaining a proper image quality using a display portion such as a permeable liquid crystal display, while securing a certain amount of composition regulation during usage under intense outdoor daylight. <P>SOLUTION: An electronic camera (1) comprises an image pick-up means (25) for photographing a color image of an object, a display unit (15) for displaying the color image, a brightness detection means (33) for detecting brightness of ambient environment of the display unit, and an image switching means (33 and 38) for usually adopting the color image as an image displayed on the display unit, but switching to a monochrome image transformed from the color image when the brightness detected by the detection means is the one making screen display of the display unit hard to see. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electronic viewfinder and an electronic camera using the same. More specifically, the present invention relates to a non-eyepiece type electronic viewfinder and an electronic camera using the same, and the electronic viewfinder capable of exhibiting the minimum function as a viewfinder even under strong external light while maintaining good display image quality of the electronic viewfinder. And an electronic camera using the same.

  A viewing window for adjusting the composition during camera shooting is called a viewfinder or simply a viewfinder. In the case of a silver halide camera, an optical viewfinder with a small glass window (a method that looks into the window frame while looking into it) was common, but in recent years, electronic cameras such as digital cameras, which have become increasingly popular, have become popular. In many cases, a small flat display device of about several inches, typically a non-eyepiece (a remote viewing method) electronic viewfinder using a liquid crystal display (LCD) is provided.

  Three types of flat display devices applicable to the viewfinder are transmissive liquid crystal, reflective liquid crystal, and transflective liquid crystal. The transmissive type uses a backlight on the back side of the liquid crystal panel as a light source, and the reflective type reflects outside light by a reflecting plate on the back side of the liquid crystal panel. The advantages / disadvantages of transmissive and reflective types are contradictory. In other words, the transmissive type, which is a self-luminous system, can provide a display image with high brightness and good image quality, but has the disadvantage that the screen is difficult to see under strong external light, while the reflective type cannot obtain a high brightness image. Although there is no image (therefore, the image quality is lower than that of the transmission type), the screen is not difficult to see even under strong external light. An organic EL display can also be applied to the viewfinder. Although the organic EL display is different from the liquid crystal in structure and light emission principle, it is common to the transmissive liquid crystal in terms of the self-luminous type, and therefore is included in the range of the transmissive liquid crystal in this specification.

  On the other hand, the transflective type having both the backlight and the reflecting plate can obtain a certain high brightness screen by the backlight, and the reflecting plate does not make it difficult to see the screen even under strong external light. It can be said that the transflective type has the advantages of both the transmissive type and the reflective type. For this reason, for example, it may be suitable for a viewfinder of an electronic camera such as a digital camera used under various brightness levels, but a part of the light of the backlight is reflected by a reflective plate interposed between the backlight and the liquid crystal panel. Therefore, there is a drawback in that sufficient luminance cannot be obtained compared to the transmission type and the image quality is poor.

  Therefore, the “transmission type liquid crystal” having the best image quality among the above three types is used for the display device, and in order to eliminate the drawbacks of the transmission type liquid crystal (the screen is difficult to see in a bright place), it is incident on the display device. The conventional technique is to detect the state of light (ratio of RGB components of the three primary colors of light) and adjust the contrast and color balance (ratio of RGB) of the color image supplied to the display device based on the ratio. It is known (for example, refer to Patent Document 1).

  According to this, the portable color display device has the advantage that a clear color display can be obtained regardless of the place, but since the use place is indefinite, the brightness condition for each use place is not constant, and therefore Depending on the place of use, the contrast and color balance of the display may be lost, but as described above, the contrast and color balance are adjusted according to the state of light incident on the display device. Color images can be displayed.

JP 2000-231092 A

The main point of the above prior art is to “display a bright and clear color image”. This is also clear from the fact that the specific adjustment target is limited to “contrast” and “color balance”.
However, depending on the place of use, it may be unavoidably used under intense external light that exceeds the adjustment limits of contrast and color balance. For example, there is a case where an electronic camera such as a digital camera does not want to miss a valuable shutter opportunity. In such a case, the image quality sufficient to understand the shooting composition is sufficient for the time being, and it is not necessary to continue to be concerned with “bright and clear color images” as in the prior art. This is because, when the contrast and color balance cannot be adjusted, the electronic viewfinder can no longer function and the user must give up shooting.

  As described above, in the above-described conventional technology, under intense light exceeding the adjustment limits of contrast and color balance, it can no longer serve as an electronic viewfinder and abandon precious shutter opportunities. There is a problem of not getting.

  Therefore, an object of the present invention is to solve the above-mentioned problems, specifically, in the case of using under intense external light while pursuing good image quality using a display unit such as a transmissive liquid crystal In the meantime, an object of the present invention is to provide an electronic viewfinder capable of adjusting the composition to some extent and an electronic camera using the electronic viewfinder.

The invention according to claim 1 is a display unit for displaying an image, brightness detection means for detecting the brightness of the surrounding environment of the display unit, and the image normally displayed on the display unit is a color image, When the brightness detected by the detection means is a predetermined brightness that makes it difficult to see the screen display of the display unit, an image displayed on the display unit is converted from the color image to the color image. And an image switching means for switching to the electronic viewfinder.
According to a second aspect of the present invention, the image switching means usually uses a color image as an image to be displayed on the display unit, and the brightness detected by the detection unit makes the screen display of the display unit difficult to see. When the first level is equivalent to the brightness of the image, the image displayed on the display unit is switched from a color image to a color image in which the saturation of the color image is emphasized, and the brightness is further changed to the display unit. The image displayed on the display unit is switched to a color image that has undergone image conversion processing when the second level corresponds to a predetermined brightness that makes the screen display more difficult to see. 1 is an electronic viewfinder.
A third aspect of the present invention is the electronic viewfinder according to the first or second aspect, wherein the image subjected to the image conversion process is obtained by converting the color image into a monochrome multi-tone image.
According to a fourth aspect of the present invention, in the electronic finder according to the first or second aspect, the image conversion process is performed by converting the color image into a black and white two-tone image.
According to a fifth aspect of the present invention, in the electronic finder according to the first or second aspect, the image switching means switches the image at a different brightness level in accordance with a brightness change direction.
According to a sixth aspect of the present invention, there is provided an imaging unit that captures a color image of a subject, a display unit that displays the color image, a brightness detection unit that detects brightness of an environment around the display unit, When the image displayed on the display unit is the color image, and the brightness detected by the detection unit is a predetermined brightness that makes it difficult to see the screen display of the display unit, the image displayed on the display unit And an image switching means for switching the color image from the color image to an image converted image of the color image.
According to the seventh aspect of the present invention, the image switching unit normally uses the color image as the image displayed on the display unit, while the brightness detected by the detection unit makes the screen display of the display unit difficult to see. When the first level corresponding to the predetermined brightness, the image displayed on the display unit is switched from the color image to a color image in which the saturation of the color image is emphasized, and the brightness is When the second level corresponding to a predetermined brightness that makes the screen display of the display unit more difficult to see, the image displayed on the display unit is switched to a color image that has undergone image conversion processing. An electronic camera according to claim 6.
The invention according to claim 8 is the electronic camera according to claim 6 or 7, wherein the image subjected to the image conversion process is obtained by converting the color image into a monochrome multi-tone image.
The invention according to claim 9 is the electronic camera according to claim 6 or 7, wherein the image subjected to the image conversion process is obtained by converting the color image into a monochrome two-tone image.
The invention described in claim 10 is characterized in that the brightness detection means detects the brightness of the surrounding environment of the display unit from the brightness information of the color image imaged by the imaging means. Is an electronic camera.
The invention according to claim 11 is characterized in that the brightness detecting means detects the brightness of the surrounding environment of the display unit from the intensity of light incident on the display screen of the display unit. Is an electronic camera.
According to a twelfth aspect of the present invention, in the electronic camera according to the sixth or seventh aspect, the image switching unit switches an image at a different brightness level in accordance with a brightness change direction.

According to the first aspect of the present invention, a color image is normally displayed on the display unit for displaying an image, while the brightness of the surrounding environment of the display unit is a predetermined brightness that makes it difficult to see the screen display of the display unit. In such a case, an image converted from the color image is displayed. Here, a color image is excellent in image quality, and a color image obtained by image conversion processing, for example, a black and white image is inferior in image quality, but has excellent visibility in a bright place. By switching between color image and image conversion processing according to the brightness, while pursuing the advantages (good image quality) of transmissive liquid crystal, it is a certain composition for the time being used under intense external light An electronic viewfinder that can be adjusted can be provided.
In the invention described in claim 2, when the brightness of the surrounding environment of the display unit increases, the color image is first switched from the color image to a color image in which the saturation of the color image is emphasized, and when the brightness further increases, the saturation is increased. Is switched from a color image with emphasis to a color image obtained by image conversion processing, for example, a monochrome image. The image quality of a color image with enhanced saturation is between the original color image and the black and white image, and is between the color image and black and white image from which the visibility in a bright place is also based. For this reason, the color image is directly switched from the original color image to the monochrome image by gradually switching from the color image to the color image with enhanced saturation, and further from the color image with enhanced saturation to the monochrome image. Compared to, it is possible to avoid sudden changes in the image and eliminate the sense of incongruity, and to make the image of intermediate brightness that is frequently used a color image with enhanced saturation, so the color of the image is not lost. Thus, it can be made practically preferable.
According to the third aspect of the present invention, when the screen of the display unit has a predetermined brightness that makes it difficult to see, a monochrome multi-tone image is displayed on the display unit. A black and white multi-tone image is a monochrome image obtained by removing the color from the original color image, so that the visibility of the image is not lost even under strong external light, and there is a multi-level between black level and white level. Since it is a so-called gray-tone image that has been adjusted, detailed information in the image is not lost.
According to the fourth aspect of the present invention, when the brightness of the screen of the display unit becomes difficult to see, a monochrome two-tone image is displayed on the display unit. A black and white two-tone image is a monochrome image obtained by binarizing the original color image. Therefore, the visibility of the image is not lost even under strong external light, and it has only two information, black level and white level. Therefore, although it is inferior in the readability of fine information in the image, it is much better than the above-described black and white multi-tone image in terms of visibility of the image under strong external light.
In the invention of claim 5, for example, if the change direction of brightness is “bright → dark” and “dark → bright”, at the time of change of “bright → dark” and at the time of change of “dark → bright” Images can be switched at different brightness levels. Therefore, it is possible to give hysteresis characteristics to the switching of images, avoiding frequent switching of images, and making it practically preferable.
In the invention described in claim 6, a color image normally captured by the imaging means is displayed on the display unit that displays the image, while the brightness of the surrounding environment of the display unit displays the screen display of the display unit. When a predetermined brightness that makes it difficult to see is displayed, an image converted from the color image, for example, a monochrome image is displayed. Here, color images are excellent in image quality, and black and white images are inferior in image quality, but are excellent in visibility in bright places. As described above, switching between color images and black and white images according to the brightness is performed. Accordingly, it is possible to provide an electronic camera capable of adjusting the composition to some extent even when used under intense external light while pursuing the advantages (good image quality) of the transmissive liquid crystal.
According to the seventh aspect of the invention, when the brightness of the surrounding environment of the display unit increases, the color image is first switched from a color image to a color image in which the saturation of the color image is emphasized. Is switched from a color image with emphasis to a color image obtained by image conversion processing, for example, a monochrome image. The image quality of a color image with enhanced saturation is between the original color image and the black and white image, and is between the color image and black and white image from which the visibility in a bright place is also based. For this reason, the color image is directly switched from the original color image to the monochrome image by gradually switching from the color image to the color image with enhanced saturation, and further from the color image with enhanced saturation to the monochrome image. Compared to, it is possible to avoid sudden changes in the image and eliminate the sense of incongruity, and to make the image of intermediate brightness that is frequently used a color image with enhanced saturation, so the color of the image is not lost. Thus, it can be made practically preferable.
According to the eighth aspect of the present invention, when the screen of the display unit has a predetermined brightness that makes it difficult to see, a monochrome multi-tone image is displayed on the display unit. A black and white multi-tone image is a monochrome image in which the color is removed from the original color image, so the visibility of the image is not lost even under strong external light, and the gradation is between black level and white level. Since it is also a so-called gray-tone image, detailed information in the image is not lost.
According to the ninth aspect of the present invention, when the screen of the display unit has a predetermined brightness that makes it difficult to see, a monochrome two-tone image is displayed on the display unit. A black and white two-tone image is a monochrome image obtained by binarizing the original color image. Therefore, the visibility of the image is not lost even under strong external light, and it has only two information, black level and white level. Therefore, although it is inferior in the readability of fine information in the image, it is much better than the above-described black and white multi-tone image in terms of visibility of the image under strong external light.
In the invention according to claim 10, since the brightness of the surrounding environment of the display unit is detected from the color image picked up by the image pickup means, it is not necessary to separately provide a light detection means, and the cost is not increased.
In the invention described in claim 11, since the light detection means is provided, a slight increase in cost is inevitable, but this light detection means is light incident on the display screen of the display section, that is, light that causes the display section to be difficult to see. Is detected directly, so that the light detection accuracy is high and the image can be switched appropriately compared to the case where the brightness of the surrounding environment of the display unit is detected from the color image captured by the imaging means. .
In the invention of claim 12, for example, if the change direction of brightness is “bright → dark” and “dark → bright”, at the time of change of “bright → dark” and at the time of change of “dark → bright” Images can be switched at different brightness levels. Therefore, it is possible to give hysteresis characteristics to the switching of images, avoiding frequent switching of images, and making it practically preferable.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, taking a digital camera as an example. It should be noted that the specific details or examples in the following description and the illustrations of numerical values, character strings, and other symbols are only for reference in order to clarify the idea of the present invention, and the present invention may be used in whole or in part. Obviously, the idea of the invention is not limited. In addition, a well-known technique, a well-known procedure, a well-known architecture, a well-known circuit configuration, and the like (hereinafter, “well-known matter”) are not described in detail, but this is also to simplify the description. Not all or part of the matter is intentionally excluded. Such well-known matters are known to those skilled in the art at the time of filing of the present invention, and are naturally included in the following description.

First, the configuration of the digital camera 1 (electronic camera) will be described.
FIG. 1 is a front view and a rear view of the digital camera 1. In this figure, although not particularly limited, the digital camera 1 has a retractable lens barrel 3, a strobe light emission window 4, an optical viewfinder front window 5 and the like disposed on the front surface of a box-shaped camera body 2. The power switch 6 and the shutter button 7 are arranged on the upper surface of the camera 2, and the optical viewfinder rear window 8, the shooting mode / playback mode switch 9, the zoom operation switch 10, the MENU button 11, A horizontal movement button 12, a SET button 13, a DISP button 14, and a transmissive liquid crystal monitor 15 (display unit, electronic viewfinder) having a display screen with a size of several inches are arranged. In addition, the camera body The lid 16 is provided on the bottom surface of the camera body 2 and the lid 16 is opened to be mounted inside the camera body 2. Tteri 17 and external memory 18 of large capacity such as a card type memory, a card type hard disk has to be detachable.

  FIG. 2 is an internal block diagram of the digital camera 1. In this figure, the digital camera 1 can be classified into an imaging system 19, a control system 20, an image storage system 21, a display system 22, an operation system 23, and the like according to functions.

  Explaining for each of these systems, the image pickup system 19 includes a photographic lens group 24 with a zoom function and an autofocus function housed in the lens barrel 3 on the front surface of the body, and two subject images that have passed through the photographic lens group 24. An electronic imaging unit 25 (imaging means) made up of a CCD (Charge Coupled Devices), a CMOS (Complementary Metal Oxide Semiconductor), or the like for converting into a three-dimensional color image signal, and a color image signal from the electronic imaging unit 25 is required. A video processing unit 26 that performs image processing, an image memory 27 that temporarily stores a color image signal after image processing, and a focus driving unit 28 that drives a focus mechanism (not shown) of the lens barrel 3; The zoom driving unit 29 for driving the zoom mechanism, the strobe 30 provided in the strobe light emission window 4 on the front surface of the body, and the strobe 30 are driven. And a shooting control unit 32 for controlling each of these units (the electronic imaging unit 25, the video processing unit 26, the focus driving unit 28, the zoom driving unit 29, and the strobe driving unit 31).

  The control system 20 is necessary for the operation of the central processing unit (hereinafter referred to as CPU) 33 (detection means, image switching means) that controls each of the above systems to control the operation of the digital camera 1 in a concentrated manner. Program memory 34 for storing various control programs and data in a non-volatile manner and user-specific data, for example, ON / OFF data of “liquid crystal display mode automatic setting” arbitrarily set by the MENU processing described later is non-volatile and rewritable And a user data memory 35 stored therein.

  The image storage system 21 includes a memory interface unit 36 and an external memory 18 that is detachably connected to the memory interface unit 36. The display system 22 includes a display control unit 38 (image switching means) including a video memory (VRAM 37) that temporarily stores display data appropriately output from the CPU 33, and a liquid crystal monitor that displays an output signal of the display control unit 38. 15. The detailed configuration of the display control unit 38 will be described later.

  The operation system 23 includes various operation buttons provided on each part of the camera body 2, that is, a shutter button 7, a shooting mode / playback mode switching switch 9, a zoom operation switch 10, a MENU button 11, an up / down / left / right movement button 12. , The operation input unit 39 including the SET button 13 and the DISP button 14, and an input circuit 40 for inputting an operation signal from the operation input unit 39 to the CPU 33.

  FIG. 3 is a memory map diagram of the digital camera 1. The long side of the vertical rectangle shown in the figure represents the range of addresses accessible from the CPU 33. For example, assuming that the top is the lowest address (start address at power-on) and the bottom is the highest address, a predetermined range including the lowest address is assigned to the program memory 34, and other overlaps are made. The areas not to be assigned are allocated to the user data memory 35 and the external memory 18, respectively.

  When the digital camera 1 is turned on, the CPU 33 accesses the lowest address of the memory map, starts the control program from the address written in the lowest address, and performs the required operation of the digital camera 1, that is, An image shooting mode and a captured image playback mode are executed, or various setting processing for the shooting mode and various setting processing for the playback mode are executed as necessary. Further, the CPU 33 accesses an arbitrary address of the user data memory 35 as necessary, and stores user-specific data, for example, ON / OFF data of “liquid crystal display mode automatic setting” arbitrarily set by a MENU process described later. It is stored in the area 35a, updated, or accessed to an arbitrary address in the external memory 18 to store photographed image data or read photographed image data.

  FIG. 4 is a detailed configuration diagram of the display control unit 38. In this figure, the display control unit 38 generates display data appropriately output from the CPU 33, that is, after being generated by the electronic imaging unit 25 of the imaging system 19 and subjected to required image processing by the video signal processing unit 26, A black-and-white multi-tone image conversion unit 41 that includes a video memory (VRAM 37) that temporarily stores a two-dimensional color image signal written in the image memory 27 and converts the color image signal into a black-and-white multi-tone image; And a selection unit 42 for selecting either a color image signal held in the VRAM 37 or a monochrome multi-tone image converted by the monochrome multi-tone image conversion unit 41 in accordance with a selection signal from the CPU 33. The image (color image or monochrome multi-tone image) selected by the unit 42 is output to the liquid crystal monitor 18.

  Here, a black and white multi-tone image can be generated, for example, by separating a color image signal into a luminance component (Y) and a color component (C) and extracting only the luminance component (Y). The image having only the luminance component (Y) generated in this way includes a black level having the lowest luminance and a white level having the highest luminance, and a multi-gradation (for example, 256 gradations) obtained by subdividing those levels. ), A so-called grayscale monochrome image, that is, a monochrome image without color.

Next, the operation of the digital camera 1 having the above configuration will be described.
FIG. 5 is a diagram showing an overall operation flowchart of the digital camera 1. In this figure, when the power switch 6 of the digital camera 1 is turned on, first, the current switch position of the shooting mode / playback mode switch 9 is checked to determine whether it is “shooting mode” or “playback mode”. (Step S10). If the determination result is “reproduction mode”, a required reproduction mode process is executed (step S11), and if it is “shooting mode”, the following shooting mode process is executed. The reproduction mode processing is a mode in which photographed image data is read from the external memory 18 and reproduced and displayed on the liquid crystal monitor 15. In this reproduction mode, the selection unit 42 of the display control unit 38 selects only the color image signal held in the VRAM 37 and outputs it to the liquid crystal monitor 15.

  The flow of the shooting mode process is roughly as follows. First, it is determined whether or not the MENU button 11 is pressed down (step S12). If the MENU button 11 is pressed down, the MENU processing for the shooting mode (step S13) is executed, and then the process returns to step S10 again.

  FIG. 6 is a flowchart of the MENU process for the shooting mode. In this flowchart, first, a shooting mode menu screen is displayed on the liquid crystal monitor 15 (step S13a). Next, a branch determination corresponding to the selection operation of the menu item by the user is performed (step S13b). If no menu item is selected, it is determined that the MENU button 11 is pressed again (step S13c), and the menu item must be pressed down. For example, the branch determination in step S13b is repeated. On the other hand, if the MENU button 11 is pressed, the shooting mode menu screen is cleared (step S13d), and the flowchart ends.

  In branch determination in step S13b, various setting menus in the shooting mode, for example, "shooting mode" such as still image shooting and moving image shooting, "size" for specifying the number of pixels of the shot image, and the compression rate of the shot image are set. In addition to “image quality” for designating, etc., branch determination of any “liquid crystal display mode” unique to the present embodiment is performed, and processing corresponding to the determination result is executed. For example, when the “liquid crystal display mode” is determined, it is determined whether or not the user's setting value (liquid crystal display mode automatic setting on / off) is changed (step S13e). The process of writing the change contents in the predetermined area 35a (see FIG. 3) of 35 (step S13f) is executed.

  FIG. 7 is a diagram showing a shooting mode menu screen 43. The shooting mode menu screen 43 displayed on the liquid crystal monitor 15 includes menu items such as a liquid crystal display mode 44, a shooting mode 45, a size 46, and an image quality 47, for example. When one of the menu items is selected by the user, the above-described branch determination (step S13b in FIG. 6) is established, and processing corresponding to the selected menu item is executed. For example, when the liquid crystal display mode 44 is selected, the liquid crystal display mode sub-screen 48 is displayed, and when either the off button 49 or the on button 50 of the liquid crystal display mode sub-screen 48 is selected, the user data memory The contents corresponding to the selection button (on / off of automatic setting of the liquid crystal display mode) are written in 35 predetermined areas 35a (see FIG. 3).

  Returning to FIG. 5 again, when the determination result in step S12 is “NO”, that is, when the MENU button 11 is not depressed, the CCD image is read (step S14), and then the liquid crystal display mode is automatically set. ON / OFF determination is executed (step S15). The “CCD image” is a two-dimensional color image signal that is generated by the electronic image pickup unit 25 of the image pickup system 19 and is subjected to required image processing by the video signal processing unit 26 and then written in the image memory 27. Say. Further, “ON / OFF of liquid crystal display mode automatic setting” means data written in a predetermined area 35a (see FIG. 3) of the user data memory 35 by the MENU processing for the shooting mode (liquid crystal display mode automatic setting is set). On or off).

  For convenience of explanation, it is assumed that the liquid crystal display mode automatic setting is “off”. In this case, the determination result in step S15 is “NO”, a CCD image, that is, an image generated by the electronic image pickup unit 25 of the image pickup system 19 and subjected to required image processing by the video signal processing unit 26, is then stored in the image memory 27. The two-dimensional color image signal written in is directly displayed on the liquid crystal monitor 15 as a through image for composition confirmation (step S16). When the number of pixels of the CCD image and the number of pixels of the liquid crystal monitor 15 do not match, an image that has been deformed (reduced or enlarged) so that the number of pixels of the CCD image matches the number of pixels of the liquid crystal monitor 15 is used as described above. It is a through image.

  Next, it is determined whether or not the shutter button 7 is depressed (step S17). If the shutter button 7 is not depressed, the process returns to step S10. On the other hand, if the shutter button 7 is depressed, shooting is performed ( Step S18), the captured image data is stored as it is (in the case of so-called RAW image capturing) or compressed (for example, Exif format) and stored in a free area of the external memory 18 (step S19), and then the process returns to step S10 again. .

  Thus, in the flowchart shown in the figure, when the liquid crystal display mode automatic setting is “off”, a color through image is always displayed on the liquid crystal monitor 15 and the composition is adjusted while viewing the color through image. When the shutter button 7 is pressed down when the desired composition is obtained, shooting is performed in response to the operation, and the shot image is recorded in the external memory 18. Accordingly, the liquid crystal monitor 15 in this case functions as an “electronic viewfinder” that always displays a color through image.

  On the other hand, when the liquid crystal display mode automatic setting is “off”, the determination result in step S15 is “YES”, and thus the characteristic processing (step S20) surrounded by the broken line in the figure is performed. After execution, it is determined whether or not the shutter button 7 is pressed down, shooting is performed, and the captured image is recorded in the external memory 18.

  That is, in this characteristic process (step S20), first, the brightness of the CCD image is detected (step S20a). “Brightness” of a CCD image refers to an average luminance value of all pixels constituting the image or pixels constituting a specific area (for example, an area of an arbitrary size in the central portion of the image). In general, the brightness of one pixel can be obtained by multiplying the R, G, and B values of that pixel by a predetermined coefficient and adding them. For example, “pixel brightness = R × 0.30 + G × 0.59 + B × 0.11”. Or, the “brightness” of an image can be expressed in a bar graph (frequency distribution diagram) by dividing the data range of pixels constituting the image into several categories and counting the number of data (frequency) in each category. It can also be obtained by analyzing a so-called histogram. Since the vertical axis of the histogram represents the appearance frequency and the horizontal axis represents the light and shade level, it can be determined that the image is dark when the histogram data is biased to the left, and the image is bright when it is biased to the right. It can be judged that there is.

  When the brightness of the CCD image is detected in this way, the brightness is then compared with a predetermined threshold SL to determine whether or not “brightness <threshold SL” (step S20b). Here, the threshold value SL is a value corresponding to the brightness of the CCD image under intense external light that makes it difficult to see the screen of the liquid crystal monitor 15.

  When the determination result in step S20b is “YES”, that is, the brightness of the CCD image at that time corresponds to the brightness of the CCD image under intense external light that makes it difficult to see the screen of the liquid crystal monitor 15. When the value (threshold value SL) is equal to or less than the threshold value SL, it is determined that there is no difficulty in viewing the screen due to the influence of external light even if a color through image is displayed on the liquid crystal monitor 15, and the process proceeds to step S16 in FIG. The two-dimensional color image signal written in the memory 27 is displayed on the liquid crystal monitor 15 as it is as a through image for composition confirmation. When the number of pixels of the CCD image and the number of pixels of the liquid crystal monitor 15 do not match, an image that has been deformed (reduced or enlarged) so that the number of pixels of the CCD image matches the number of pixels of the liquid crystal monitor 15 is used as described above. It is a through image.

  On the other hand, when the determination result in step S20b is “NO”, that is, the brightness of the CCD image at that time corresponds to the brightness of the CCD image under intense external light that makes the screen of the liquid crystal monitor 15 difficult to see. When it is not less than the value (threshold value SL), when a color through image is displayed on the liquid crystal monitor 15, it is determined that there is a high probability that the screen will be difficult to see due to the influence of intense external light. The image is converted into a gradation image (step S20c), and the black and white multi-gradation image is displayed on the liquid crystal monitor 15 as a through image for composition confirmation (step S20d), and then directly passes through step S16 in FIG. The process proceeds to step S17. If the number of pixels of the monochrome multi-tone image and the number of pixels of the liquid crystal monitor 15 do not match, deformation processing (reduction or enlargement) is performed so that the number of pixels of the monochrome multi-tone image matches the number of pixels of the liquid crystal monitor 15. ) Is set as the through image.

  As described above, in the digital camera 1 of the present embodiment, the mode determination is performed after the power is turned on, and either the “reproduction mode” for reproducing the photographed image or the “photographing mode” for image photographing is executed. . When the MENU button 11 is pressed during the shooting mode, the shooting mode MENU process is executed to enable various user settings necessary for the shooting mode.

  One of the various user settings required for the shooting mode is “liquid crystal display mode automatic setting” (see FIG. 7). If this “liquid crystal display mode automatic setting” is set to “off”, the digital display is performed as usual. While the LCD monitor 15 of the camera 1 can be used as a “color” electronic viewfinder, if this “LCD display mode automatic setting” is set to “ON” as necessary, the LCD monitor 15 of the digital camera 1 Can be used as an electronic viewfinder that automatically switches between “color” and “black and white multi-gradation”.

  Here, when “LCD display mode automatic setting” is set to “ON”, whether the liquid crystal monitor 15 is a “color” electronic finder or a “black and white multi-gradation” electronic finder is determined solely by that. It is determined depending on the brightness of the CCD image at the time. If the brightness is equal to or less than a threshold value SL (a value corresponding to the brightness of a CCD image under intense external light that makes it difficult to see the screen of the liquid crystal monitor 15), the liquid crystal monitor 15 is a “color” electronic device. If it becomes a viewfinder and its brightness is not less than a threshold value SL (a value corresponding to the brightness of a CCD image under intense external light that makes it difficult to see the screen of the liquid crystal monitor 15), the liquid crystal monitor 15 It becomes an electronic viewfinder of “black and white multi-gradation”.

  FIG. 8 is a relationship diagram between the brightness of the CCD image and the threshold value SL. In this figure, the vertical axis represents the brightness of the CCD image, and the brightness increases as it goes up and becomes darker as it goes down. As described above, the threshold value SL is “a value corresponding to the brightness of the CCD image under intense external light that makes it difficult to see the screen of the liquid crystal monitor 15”. This threshold value SL may be set to an appropriate value by trial and error by repeating experiments and the like. In the illustrated example, the brightness axis (vertical axis) is set at a substantially central portion, but this is for convenience of explanation.

  As described above, when the “liquid crystal display mode automatic setting” is turned on, the digital camera 1 according to the present embodiment is configured such that the liquid crystal monitor 15 becomes a “color” electronic viewfinder with this threshold value SL as a boundary. , Become a black-and-white multi-tone electronic viewfinder. That is, in the area below the threshold SL (area in the darkening direction), the liquid crystal monitor 15 becomes a “color” electronic viewfinder, and in the area above the threshold SL (area in the brightening direction). The liquid crystal monitor 15 becomes a “monochrome multi-tone” electronic viewfinder.

  Therefore, according to the present embodiment, in the case of a CCD image with normal brightness, the liquid crystal monitor 15 is used as a “color” electronic viewfinder, and a “bright and clear color image” which is a feature of the transmissive liquid crystal is obtained. While fine composition adjustment is possible, the LCD monitor 15 should be used when it is used under strong external light that exposes the defects of the transmissive liquid crystal (the screen is difficult to see in bright places). It can be used as a “black and white multi-tone” electronic viewfinder. As a result, black-and-white multi-tone display images are more visible under strong light than color images, so at least composition adjustment can be performed without any problem, and valuable photo opportunities can be missed. A special effect is obtained.

  FIG. 9 is a use situation diagram of the digital camera 1 of the present embodiment. In this figure, the liquid crystal monitor 15 of the digital camera 1 is a “color” electronic viewfinder when shooting under normal brightness, for example, when shooting under indoor lighting, as shown in FIG. However, as shown in (b), when photographing under intense external light such as sunlight, the liquid crystal monitor 15 of the digital camera 1 is an electronic viewfinder of “monochrome multi-gradation”. For this reason, the photographer 51 can confirm the composition of the subject 52 using the liquid crystal monitor 15 at any time of photographing, so that the photographing can be performed without delay, and in particular, a shutter chance under intense external light is obtained. Never miss it.

  The present invention is not limited to the above embodiments, and various modifications and developments are naturally included within the scope of the technical idea. For example, the following may be adopted.

FIG. 10 is a main part flowchart corresponding to the characteristic process (step S20 in FIG. 5) showing a first modification of the present embodiment. The difference from the characteristic processing described above is that the brightness change direction is determined, and different threshold values SL _L and SL _H (where SL _L <SL _H ) are applied for each brightness change direction. In the point. That is, also in this first modification, first, the brightness of the CCD image of the current frame is detected (step S20a), but after the brightness is detected, the direction of change in brightness is determined (step S20e). Is different. “Brightness change direction” means that the difference between the brightness of the CCD image one frame or several frames before and the brightness of the CCD image of the current frame is represented by a direction. For example, when the brightness of the CCD image of the current frame is brighter than the brightness of the CCD image one frame or several frames before, the change direction of the brightness is said to be “dark → bright”. The opposite direction of brightness change is “bright → dark”. When the brightness does not change, for example, it may be regarded as “dark → bright” or “bright → dark”.

Next, when the change direction of the brightness is “bright → dark”, the brightness of the CCD image of the current frame is compared with the first threshold value SL _L, and “brightness <first threshold value SL” is compared. It is determined whether or not “ _L ” (step S20f). Here, the first threshold value SL _L is a value corresponding to the brightness of the CCD image under strong external light that makes it difficult to see the screen of the liquid crystal monitor 15.

When the determination result in step S20f is “YES”, that is, the brightness of the CCD image in the current frame corresponds to the brightness of the CCD image under strong external light that makes it difficult to see the screen of the liquid crystal monitor 15. When the value (first threshold value SL _L ) or less, it is determined that the difficulty in viewing the screen due to the influence of external light does not occur even if a color through image is displayed on the liquid crystal monitor 15, and the process proceeds to step S16 in FIG. Then, the two-dimensional color image signal written in the image memory 27 is displayed on the liquid crystal monitor 15 as a through image for composition confirmation. When the number of pixels of the CCD image and the number of pixels of the liquid crystal monitor 15 do not match, an image that has been deformed (reduced or enlarged) so that the number of pixels of the CCD image matches the number of pixels of the liquid crystal monitor 15 is used as described above. It is a through image.

On the other hand, when the determination result in step S20f is “NO”, that is, the brightness of the CCD image of the current frame corresponds to the brightness of the CCD image under strong external light that makes the screen of the liquid crystal monitor 15 difficult to see. When it is not less than the value (first threshold value SL _L ), when a color through image is displayed on the liquid crystal monitor 15, it is determined that there is a high probability that the screen will be difficult to see due to the influence of intense external light. The image is converted into a black-and-white multi-tone image (step S20c), and the black-and-white multi-tone image is displayed on the liquid crystal monitor 15 as a through image for composition confirmation (step S20d), and then step S16 in FIG. 5 is passed. The process proceeds directly to step S17 in FIG. If the number of pixels of the monochrome multi-tone image and the number of pixels of the liquid crystal monitor 15 do not match, deformation processing (reduction or enlargement) is performed so that the number of pixels of the monochrome multi-tone image matches the number of pixels of the liquid crystal monitor 15. ) Is set as the through image.

Next, when the change direction of the brightness is “dark → light”, the brightness of the CCD image of the current frame is compared with the second threshold value SL _H, and “brightness> second threshold value SL” is compared. It is determined whether or not “ _H ” (step S20g). Here, the second threshold value SL _H is a value corresponding to the brightness of the CCD image under intense external light that makes it difficult to see the screen of the liquid crystal monitor 15. _Although it is similar to _L , it is different in that the value is slightly larger than the first threshold value SL _L. That is, there is a relationship of “SL _L <SL _H ”. The reason for making the relationship “SL _L <SL _H ” will be described later.

When the determination result in step S20g is “NO”, that is, the brightness of the CCD image in the current frame corresponds to the brightness of the CCD image under strong external light that makes it difficult to see the screen of the liquid crystal monitor 15. If it is not equal to or greater than the value (second threshold value SL _H ), it is determined that it is not difficult to see the screen due to the influence of external light even if a color through image is displayed on the liquid crystal monitor 15, and the process proceeds to step S16 in FIG. Then, the two-dimensional color image signal written in the image memory 27 is displayed on the liquid crystal monitor 15 as a through image for composition confirmation. When the number of pixels of the CCD image and the number of pixels of the liquid crystal monitor 15 do not match, an image that has been deformed (reduced or enlarged) so that the number of pixels of the CCD image matches the number of pixels of the liquid crystal monitor 15 is used as described above. It is a through image.

On the other hand, when the determination result in step S20g is “YES”, that is, the brightness of the CCD image of the current frame corresponds to the brightness of the CCD image under strong external light that makes it difficult to see the screen of the liquid crystal monitor 15. If the color through image is displayed on the liquid crystal monitor 15 when the value (second threshold value SL _H ) or more, it is determined that there is a high probability that the screen will be difficult to see due to the influence of intense external light. The image is converted into a black-and-white multi-tone image (step S20c), and the black-and-white multi-tone image is displayed on the liquid crystal monitor 15 as a through image for composition confirmation (step S20d), and then step S16 in FIG. 5 is passed. The process proceeds directly to step S17 in FIG. If the number of pixels of the monochrome multi-tone image and the number of pixels of the liquid crystal monitor 15 do not match, deformation processing (reduction or enlargement) is performed so that the number of pixels of the monochrome multi-tone image matches the number of pixels of the liquid crystal monitor 15. ) Is set as the through image.

FIG. 11 is a relationship diagram between the brightness of the CCD image and the two threshold values SL _L and SL _H. In this figure, the vertical axis represents the brightness of the CCD image, and the brightness increases as it goes up and becomes darker as it goes down. As described above, the two threshold values SL _L and SL _H are “values corresponding to the brightness of the CCD image under strong external light that makes it difficult to see the screen of the liquid crystal monitor 15”, and “ There is a relationship of SL _L <SL _H.

When the “liquid crystal display mode automatic setting” is turned on, the digital camera 1 of the present embodiment is an electronic viewfinder in which the liquid crystal monitor 15 is “color” with these two threshold values SL _L and SL _H as a boundary. Or a “black and white multi-gradation” electronic viewfinder, which threshold is applied depends solely on the direction of change in brightness. In other words, the direction of change in the brightness in the case of "bright → dark", or become electronic viewfinder of a liquid crystal monitor 15 "color" to the first threshold value SL _L as a boundary, the "black-and-white multi-tone" It will be or become electronic viewfinder, if the direction of change in the brightness of "dark → bright", or become electronic viewfinder of a liquid crystal monitor 15 "color" to the second threshold value SL _H to the border, " It becomes a black-and-white multi-tone electronic viewfinder.

In this way, it is possible to provide “hysteresis characteristics” for switching between color and monochrome multi-gradation of the liquid crystal monitor 15. Therefore, frequent switching between color and black-and-white multi-gradation (chattering) when the brightness is in the vicinity of the threshold values (SL _L , SL _H ) can be avoided, which is practically preferable.

  FIG. 12 is a detailed configuration diagram of a display control unit 38 ′ (which replaces the display control unit 38 of FIG. 4) showing a second modification of the present embodiment. In this figure, the display control unit 38 ′ is appropriately output from the CPU 33, that is, after being generated by the electronic imaging unit 25 of the imaging system 19 and subjected to required image processing by the video signal processing unit 26. And a video memory (VRAM 37) that temporarily holds a two-dimensional color image signal written in the image memory 27, and that converts the color image signal into a black-and-white multi-tone image. And a monochrome two-tone image converter 53 for converting the color image signal into a monochrome two-tone image, and a color image signal held in the VRAM 37 and the monochrome multi-tone image converter 41 according to a selection signal from the CPU 33. A selection unit 42 for selecting one of the monochrome multi-tone image and the monochrome two-tone image converted by the monochrome two-tone image conversion unit 53. In outputting the selected image on the LCD monitor 18. 4 differs from the display control unit 38 in FIG. 4 in that it includes a monochrome two-tone image conversion unit 53 that converts a color image signal into a monochrome two-tone image, and three images (colors) according to a selection signal from the CPU 33. The selection unit 42 is provided for selecting any one of image / monochrome multi-tone image / monochrome two-tone image).

  A black and white two-tone image is an image in which the number of gradations of a black and white multi-tone image is “2”, and means an image having only two information of a black level and a white level. In such a black and white two-tone image, a threshold value of an appropriate size is applied to a black and white multi-tone image, and the portion exceeding the threshold value is set to the white level and the portion below the threshold value is set to the black level. Can be generated. Lowering the threshold results in a whitish image, and increasing the threshold results in a darker image. Note that a dither image representing black and white shading with a collection of small dots is also a kind of black and white two-tone image, and thus the above black and white two-tone image may be read as a dither image.

FIG. 13 is a main part flowchart of the characteristic processing (corresponding to step S20 in FIG. 5) used in combination with the display control unit 38 ′. In this figure, for detecting the brightness of the as well as CCD image (step S20a), then compares the brightness and the first threshold value SL _1, "Brightness <first threshold It is determined whether or not the value is “SL ₁ ” (step S20h). Here, the first threshold value SL ₁ is a value corresponding to the brightness of the CCD image under strong external light that makes it somewhat difficult to see the screen of the liquid crystal monitor 15.

When the determination result in step S20h is “YES”, that is, the brightness of the CCD image at that time is the brightness of the CCD image under strong external light that makes it slightly difficult to see the screen of the liquid crystal monitor 15. When the value is equal to or less than the corresponding value (first threshold value SL ₁ ), it is determined that there is no difficulty in viewing the screen due to the influence of external light even if a color through image is displayed on the liquid crystal monitor 15. Proceeding to S16, the two-dimensional color image signal written in the image memory 27 is directly displayed on the liquid crystal monitor 15 as a through image for composition confirmation. When the number of pixels of the CCD image and the number of pixels of the liquid crystal monitor 15 do not match, an image that has been deformed (reduced or enlarged) so that the number of pixels of the CCD image matches the number of pixels of the liquid crystal monitor 15 is used as described above. It is a through image.

On the other hand, when the determination result in step S20h is “NO”, that is, the brightness of the CCD image at that time is the brightness of the CCD image under strong external light that makes the screen of the liquid crystal monitor 15 “slightly” difficult to see. If it is not less than or equal to the corresponding value (first threshold value SL ₁ ), then the brightness is compared with the second threshold value SL _2, and “brightness <second threshold value SL ₂ ”. Whether or not (step S20i). Here, the second threshold value SL ₂ is a value corresponding to the brightness of the CCD image under intense external light to such an extent that the screen of the liquid crystal monitor 15 becomes “almost” invisible. The first threshold value SL ₁ and the second threshold value SL ₂ have a relationship of “SL ₁ <SL ₂ ”.

When the determination result in step S20i is “YES”, that is, the brightness of the CCD image at that time is the brightness of the CCD image under strong external light that makes the screen of the liquid crystal monitor 15 “slightly” difficult to see. A value (first value) corresponding to the brightness of the CCD image under intense external light that is equal to or greater than the corresponding value (first threshold value SL ₁ ) and is almost invisible to the screen of the liquid crystal monitor 15. In the case of the second threshold value SL ₂ ) or less, if a color through image is displayed on the liquid crystal monitor 15, it is determined that there is a high probability that the screen will be “slightly” difficult to see due to the influence of strong external light. Is converted into a monochrome multi-tone image (step S20c), and the black-and-white multi-tone image is displayed on the liquid crystal monitor 15 as a through image for composition confirmation (step S20d). Directly-up S16 to pass, the flow proceeds to step S17 in FIG. If the number of pixels of the monochrome multi-tone image and the number of pixels of the liquid crystal monitor 15 do not match, deformation processing (reduction or enlargement) is performed so that the number of pixels of the monochrome multi-tone image matches the number of pixels of the liquid crystal monitor 15. ) Is set as the through image.

On the other hand, when the determination result in step S20i is “NO”, that is, the brightness of the CCD image under strong external light at which the screen of the liquid crystal monitor 15 is “almost” invisible. If the value is not equal to or less than the value (second threshold value SL ₂ ), even if a black and white multi-tone image is displayed on the liquid crystal monitor 15, there is a probability that the screen will be “almost” invisible due to the strong external light. In this case, the CCD image is converted into a monochrome two-tone image (step S20j), and the monochrome two-tone image is displayed on the liquid crystal monitor 15 as a through image for composition confirmation (step S20k). The process proceeds directly to step S17 in FIG. If the number of pixels of the monochrome two-tone image and the number of pixels of the liquid crystal monitor 15 do not match, modification (reduction or enlargement) is performed so that the number of pixels of the monochrome two-tone image matches the number of pixels of the liquid crystal monitor 15. The image is the above-described through image.

FIG. 14 is a relationship diagram between the brightness of the CCD image and the two threshold values SL ₁ and SL ₂ . In this figure, the vertical axis represents the brightness of the CCD image, and the brightness increases as it goes up and becomes darker as it goes down. As described above, the first threshold value SL ₁ is “a value corresponding to the brightness of the CCD image under strong external light that makes the screen of the liquid crystal monitor 15 somewhat difficult to see”. The threshold value SL ₂ is “a value corresponding to the brightness of the CCD image under intense external light that makes the screen of the liquid crystal monitor 15 almost invisible” and “SL ₁ <SL ₂ ”. There is a relationship.

In the second modification, the brightness of the CCD image is divided into three zones with two threshold values SL ₁ and SL ₂ as boundaries. A color image is displayed on the LCD monitor 15 as a through image in a low-brightness zone (a brightness zone that does not make the screen difficult to see), and a moderate brightness zone (a brightness that makes the screen somewhat difficult to see). In this zone, a monochrome multi-gradation image is displayed on the liquid crystal monitor 15 as a through image, and in a high brightness zone (a brightness zone where the screen is almost invisible), a monochrome two-tone image is displayed as a through image on the liquid crystal monitor 15. To display.

  When comparing these three images (color image / black and white multi-tone image / black and white two-tone image) with respect to the brightness, the visibility of the color image is poor, and the black and white multi-tone image and the black and white two-tone image are visible. In particular, the visibility of a black and white two-tone image is considerably high, and at least a subject necessary for composition adjustment can be confirmed without any trouble even under intense external light. Therefore, according to the second modification, it is possible to obtain further light resistance, and never miss a valuable photo opportunity regardless of time and place.

It should be noted that it is preferable that the second modification also has “hysteresis characteristics”.
FIG. 15 is a main part flow chart improved so as to have a hysteresis characteristic. The difference from FIG. 13 is that the brightness change direction is determined, and threshold values SL _1L , SL _1H , SL _2L , SL _2H that differ for each brightness change direction (SL _1L <SL _1H < SL _2L <SL _2H ). That is, when the brightness of the CCD image of the current frame is detected (step S20a), the brightness change direction is determined (step S20m) after the brightness is detected. When the brightness change direction is “bright → dark”, SL _1L is set to the first threshold value SL ₁ (SL _1L → SL ₁ ), and the second threshold value SL _{2 is set.} SL _2L is set to (SL _2L → SL ₂ ), and when the direction of change in brightness is “dark → light”, SL _1H is set to the second threshold value SL ₂ (SL _1H → SL ₁ ) And SL _{2H is set} to the second threshold value SL ₂ (SL _2H → SL ₂ ), and thereafter, the same processing as step S20h to step S20k in FIG. 13 is executed.

FIG. 16 is a diagram showing the relationship between the brightness of the CCD image and the four threshold values SL _1L , SL _1H , SL _2L , and SL _2H . Of these threshold values, two threshold values SL _1L and SL _2L with a subscript “L” are used when the direction of change in brightness is “bright → dark”. The two thresholds SL _1H and SL _2H with “” are used when the direction of change in brightness is “dark → light”. Therefore, it is possible to provide a “hysteresis characteristic” for switching between color, monochrome multi-gradation, and monochrome two-gradation of the liquid crystal monitor 15, and the brightness is in the vicinity of the threshold value (SL _1L , SL _1H , SL _2L , SL _2H ). Switching between frequent color and monochrome multi-gradation or switching between monochrome multi-gradation and monochrome two-gradation at a certain time can be avoided, which can be made practically preferable.

  In the above embodiments and modifications, in order to eliminate the drawbacks of the transmissive liquid crystal monitor 15 (the screen becomes difficult to see in bright places), in such bright places, monochrome multi-gradations are used instead of color images. Although an image and a monochrome two-tone image are displayed, the present invention is not limited to this. For example, the saturation of a color image may be emphasized unless the screen is difficult to see to the extent that black and white multi-gradation or black-and-white two-gradation is used.

  Here, the way of feeling the color is subjective, but if expressed on a certain scale, it can be expressed by three of hue (Hue), brightness (Brightness) and saturation (Saturation). These are called the three attributes of color. Hue is a difference in color and has the same meaning as what we usually perceive or express as “color”, such as red, green, and blue. Lightness refers to the brightness of a color. The brightest color is white and the darkest color is black. Saturation is the vividness of color. As the saturation decreases, it becomes a color that does not feel a “dull” color, and as the saturation increases, it becomes a “glare” color.

  Of these three color attributes, “saturation” is an appropriate adjustment target for improving visibility in bright places. When the hue is adjusted, the subject's color changes, and the user feels a sense of discomfort. Because it becomes difficult to see. On the other hand, when the saturation is emphasized, the color of the subject does not change, but rather, it becomes a “glaring” feeling, and the visibility in a bright place is increased accordingly.

  FIG. 17 is an image diagram of image switching including saturation enhancement. As shown in this figure, when the brightness of the CCD image is low, importance is placed on the reproducibility of the image, and conversely, it is necessary to place importance on the visibility of the image as the brightness of the CCD image increases. Even if the brightness of the screen is low, there is an intermediate region (hatched portion) where the screen is not so difficult to see. In such an intermediate region, it is desirable to balance image visibility and image reproducibility. That is, a color image is displayed on the liquid crystal monitor 15 as a through image in the low luminance region, but a color image (however, a color with enhanced saturation and enhanced visibility for brightness) even in a brighter region (intermediate region). Image) is displayed on the liquid crystal monitor 15 as a through image. In the area where the brightness is further increased, a black and white multi-tone image emphasizing visibility is displayed on the liquid crystal monitor 15 as a through image, and in the most intense area, a monochrome two-tone image emphasizing visibility is further displayed. A through image is displayed on the liquid crystal monitor 15. In this way, it is possible to make two color images, a low-intensity area with relatively high use frequency and a brighter intermediate area, as color images, and avoid extreme image changes between these two areas. Can do. Therefore, it can be made practically preferable.

  In the above embodiment and modification, the through image display mode is switched based on the brightness of the CCD image generated by the electronic imaging unit 25 such as a CCD. However, the present invention is not limited to this.

  FIG. 18 is a diagram showing a digital camera 1 ′ in which an optical sensor 54 is provided near the liquid crystal monitor 15. In the case of the digital camera 1 ′ having such a configuration, based on the brightness detected by the optical sensor 54, a through image display mode (from a color image to a monochrome multi-tone image or a monochrome two-tone image or saturation is emphasized). Color image etc.) can be switched. Unlike the electronic imaging unit 25 that receives light from the lens barrel 3 located on the opposite surface of the liquid crystal monitor 15, the optical sensor 54 is provided on the “same surface” as the liquid crystal monitor 15. The intensity of light incident on the monitor 15 can be accurately detected. The “difficulty in viewing” of the liquid crystal monitor 15 depends solely on the intensity of light incident on the liquid crystal monitor 15, so that the through image can be obtained by directly detecting such light on the same surface by the optical sensor 54. The display mode switching control can be more accurately performed.

  In the above description, application to a digital camera is taken as an example, but the present invention is not limited to this. Any electronic camera equipped with a transmission-type electronic viewfinder dedicated to composition confirmation or a transmission-type liquid crystal monitor also used for composition confirmation, such as a digital video camera, a camera-equipped mobile phone or other portable imaging device, may be used. Also good.

  Further, in the above description, an example in which the liquid crystal monitor 15 is used as an electronic fainter is illustrated, but the present invention is not limited to this. For example, an organic EL display or other flat display device (PDP or the like) may be used.

2 is a front view and a rear view of the digital camera 1. FIG. 2 is an internal block diagram of the digital camera 1. FIG. 2 is a memory map diagram of the digital camera 1. FIG. 3 is a detailed configuration diagram of a display control unit 38. FIG. 2 is a diagram illustrating an overall operation flowchart of the digital camera 1. FIG. It is a figure which shows the flowchart of MENU processing for imaging | photography modes. It is a figure which shows the menu screen 43 for imaging | photography modes. It is a relationship diagram between the brightness of the CCD image and the threshold value SL. It is a utilization condition figure of digital camera 1 of this embodiment. It is a principal part flowchart figure equivalent to FIG.5 S20 which shows the 1st modification of this embodiment. It is a relationship diagram between the brightness of a CCD image and two threshold values SL _L and SL _H. It is a detailed block diagram of display control part 38 'which shows the 2nd modification of this embodiment. It is a principal part flowchart figure of the characteristic process used by a pair with said display control part 38 '. It is a relationship diagram between the brightness of a CCD image and two threshold values SL ₁ and SL ₂ . It is a principal part flowchart figure improved so that a hysteresis characteristic might be given. It is a relationship diagram between the brightness of a CCD image and four threshold values SL _1L , SL _1H , SL _2L , SL _2H . It is an image figure of the image change including emphasis of saturation. FIG. 2 is a diagram showing a digital camera 1 ′ provided with an optical sensor 54 near a liquid crystal monitor 15.

Explanation of symbols

1 Digital camera (electronic camera)
15 LCD monitor (display unit, electronic viewfinder)
25 Electronic imaging unit (imaging means)
33 CPU (detection means, image switching means)
38 Display control unit (image switching means)

Claims (12)

A display for displaying an image;
Brightness detection means for detecting the brightness of the surrounding environment of the display unit;
Usually, the image displayed on the display unit is a color image, and when the brightness detected by the detection unit is a predetermined brightness that makes it difficult to see the screen display of the display unit, the image is displayed on the display unit. And an image switching means for switching an image to be switched from the color image to an image converted image of the color image.   The image switching means normally uses a color image as an image to be displayed on the display unit, while the brightness detected by the detection unit corresponds to a predetermined brightness that makes it difficult to see the screen display of the display unit. The image displayed on the display unit is switched from a color image to a color image in which the saturation of the color image is emphasized, and the brightness is a predetermined value that makes the display on the display unit more difficult to see. 2. The electronic viewfinder according to claim 1, wherein an image displayed on the display unit is switched to one obtained by performing image conversion processing on the color image when the second level corresponds to the brightness of the image.   3. The electronic viewfinder according to claim 1, wherein the image subjected to the image conversion process is obtained by converting the color image into a monochrome multi-tone image.   3. The electronic viewfinder according to claim 1, wherein the image conversion process is performed by converting the color image into a monochrome two-tone image.   The electronic viewfinder according to claim 1 or 2, wherein the image switching means switches images at different brightness levels according to a brightness change direction. Imaging means for capturing a color image of the subject;
A display unit for displaying the color image;
Brightness detection means for detecting the brightness of the surrounding environment of the display unit;
Usually, the image displayed on the display unit is the color image, and when the brightness detected by the detection unit is a predetermined brightness that makes it difficult to see the screen display of the display unit, the display unit An electronic camera comprising: an image switching means for switching an image to be displayed from the color image to an image converted from the color image.   The image switching means normally uses an image displayed on the display unit as the color image, while the brightness detected by the detection means corresponds to a predetermined brightness that makes it difficult to see the screen display of the display unit. If the level is one level, the image displayed on the display unit is switched from the color image to a color image in which the saturation of the color image is emphasized, and the brightness is more difficult to see the screen display of the display unit. The electronic camera according to claim 6, wherein when the second level corresponds to a predetermined brightness, the image displayed on the display unit is switched to an image converted image of the color image.   8. The electronic camera according to claim 6, wherein the image subjected to the image conversion process is obtained by converting the color image into a monochrome multi-tone image.   8. The electronic camera according to claim 6, wherein the image subjected to the image conversion process is obtained by converting the color image into a monochrome two-tone image.   The electronic camera according to claim 6, wherein the brightness detection unit detects the brightness of an environment surrounding the display unit from brightness information of a color image captured by the imaging unit.   The electronic camera according to claim 6, wherein the brightness detection unit detects the brightness of an environment surrounding the display unit from the intensity of light incident on the display screen of the display unit.   8. The electronic camera according to claim 6, wherein the image switching unit switches the image at a different brightness level according to a brightness change direction.

Images