JP2006333052A - Exposure adjusting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exposure adjusting device that improves visibility of setting items displayed together with an image. <P>SOLUTION: A microcomputer calculates a suitable exposure value EVP based upon the detected luminance of a subject (step S201) and calculates a calculated aperture value AVM so that a value which is larger than the exposure value EVP by 8EV is set as a new target exposure value. Then when an aperture value AV can be set to the calculated aperture value AVM, the calculated aperture value AVM is set as the aperture value AV as it is (step S205). When the calculated aperture value AVM is larger than a maximum value AV<SB>max</SB>of an aperture value, the aperture value AV is set to the maximum aperture value AV<SB>max</SB>(step S204) and photographic sensitivity SV of a CCD is decreased by a specified value (steps S206 and S207). Thus, the exposure of the CCD is controlled to decrease the luminance of the subject displayed together with menu items. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an exposure adjustment device, and more particularly to an exposure adjustment device that adjusts exposure according to display of setting items for setting shooting conditions and the like.

In an apparatus capable of displaying an image such as a digital camera or a video camera, setting items for shooting and the like are displayed together with the image (see, for example, Patent Document 1). Then, the user selects a predetermined menu item or the like from setting items displayed on the screen together with the image. In this case, since the images are immediately switched according to the menu item newly set by the user, it is possible to easily confirm whether or not a desired image can be obtained prior to shooting or the like.
JP 2002-297278 A (see paragraphs [0034] to [0054], FIGS. 4 to 12)

  In an apparatus capable of displaying an image such as a digital camera, the setting item may be difficult to visually recognize depending on the displayed image or the like, for example, when the setting item is displayed in white together with a display image including a subject with extremely high brightness. is there. In this case, it becomes difficult to select setting items, and the operability of the digital camera or the like decreases.

  An object of this invention is to provide the exposure adjustment apparatus for improving the visibility of the setting item displayed with an image.

  The first exposure adjustment device of the present invention includes an imaging device that receives light from a subject to generate an image signal, a light amount adjustment unit that adjusts a light amount of light received by the imaging device, and a subject based on the image signal. Image display means for displaying the image, and menu item display means for displaying a menu item for selecting the operation content together with the image. When the menu item is displayed, the light amount adjusting means reduces the amount of light received by the image sensor as compared to when the menu item is not displayed.

  The first exposure adjustment device further includes sensitivity adjustment means for adjusting the sensitivity of the image sensor, and when the menu item is displayed, the sensitivity adjustment means causes the sensitivity of the image sensor to be higher than when the menu item is not displayed. It is preferable to reduce. Further, it is preferable that the light amount adjusting means includes at least one of a diaphragm mechanism and a neutral density filter.

  The first exposure adjustment apparatus further includes a luminance detection unit that detects the luminance of the subject, and an exposure value setting unit that sets a target exposure value of the image sensor based on the luminance of the subject detected by the luminance detection unit. When the menu item is displayed, the exposure value setting means sets a smaller target exposure value than when the menu item is not displayed, and the light amount adjusting means reduces the exposure amount of the image sensor based on the target exposure value. It is desirable to make it. Further, it is more desirable that the exposure value setting means sets a target exposure value that is larger by a predetermined value when the menu item is displayed than when the menu item is not displayed.

  It is preferable that the exposure value setting means can set a target exposure value designated by the user. The image display means displays the image as a through image, for example.

  The second exposure adjustment apparatus of the present invention adjusts the sensitivity of an image sensor that receives light from a subject to generate an image, image display means that displays an image of the subject based on an image signal, and the image sensor. Sensitivity adjustment means and menu item display means for displaying menu items for selecting operation contents together with images are provided. Then, when the menu item is displayed, the sensitivity adjusting means lowers the sensitivity of the image sensor to reduce the exposure amount of the image sensor than when the menu item is not displayed.

  ADVANTAGE OF THE INVENTION According to this invention, the exposure adjustment apparatus which improves the visibility of the setting item displayed with an image is realizable.

  FIG. 1 is a block diagram of a digital camera according to the first embodiment.

  The digital camera 10 is provided with a microcomputer 17 that controls the whole. A main switch (SWM) 11 is a switch of the digital camera 10, and the microcomputer 17 starts to operate when operated by a user and turned on. The microcomputer 17 is connected with a menu button 13, a mode dial 14, a photometric switch (SWS) 15, a release switch (SWR) 16, a cross key 21, an OK button 23, and the like, and a predetermined signal according to a user operation. Is transmitted to the microcomputer 17. In addition, the telephoto switch (SWT) 27 and the wide-angle switch (SWW) 28 are turned on by depressing the left or right area of a zoom switch (not shown) provided on the surface of the digital camera 10, respectively. A signal for wide-angle shooting is transmitted to the microcomputer 17.

  When the mode dial 14 is set at a predetermined rotational position, signals corresponding to a shooting mode for shooting a subject, a playback mode for playing back a shot image, and the like are sent to the microcomputer 17 to set each mode. The EEPROM 44 stores various data necessary for signal processing of the microcomputer 17 that is read according to each setting mode. In the shooting mode, the subject image is displayed on the LCD monitor 22 as follows.

  First, the CCD 38 receives reflected light from the subject via the photographing lens 30, and charges corresponding to the image are generated in a number of photoelectric conversion elements provided in the CCD 38. The charge signal read from the CCD 38 based on the control by the CCD drive circuit 36, that is, the image signal is reduced in noise in the CDS circuit 39, and the A / D converter 40 converts the analog image signal into a digital image signal. Converted. The digitized image signal is sent to the microcomputer 17.

  In a signal processing circuit (not shown) in the microcomputer 17, the digital image signal is subjected to various signal processing such as white balance adjustment and gamma correction to generate a luminance signal and a color difference signal. The generated luminance signal and color difference signal, that is, image data are recorded in the DRAM 42. The photometric operation of the subject by the microcomputer 17 is performed based on the generated luminance signal. In the present embodiment, for example, the effective imaging area of the CCD 38 is divided into 16 areas of 4 × 4 in the vertical and horizontal directions, and appropriate exposure is performed according to a predetermined algorithm based on the luminance value averaged for each of the divided areas. The microcomputer 17 calculates a value (target exposure value), that is, an appropriate exposure amount of the CCD 38.

  The generation of the image data is periodically updated, and a through image is displayed on the LCD monitor 22 as a real-time moving image. Note that the number of display pixels of the LCD monitor 22 is 640 × 480 pixels, for example, which is smaller than the effective number of pixels of the CCD 38, so that the subject image image data displayed on the LCD monitor 22 is thinned by the microcomputer 17. Is given. When the menu button 13 is pressed, characters, numbers, etc. indicating predetermined menu items are superimposed on the subject image and displayed on the LCD monitor 22 based on the control of the microcomputer 17.

  The user selects various operating modes and various operation items for shooting or image playback displayed on the LCD monitor 22 for each menu item, and executes desired operation contents on the digital camera 10. Can be made. The menu items include, for example, recording size (image resolution), image quality, white balance, and the like. Then, a signal corresponding to the selected parameter is sent to the microcomputer 17 so that the desired parameter is used for photographing the subject or reproducing the image. Here, the parameters include a plurality of selectable operation modes set in advance in addition to numerical values selectable by the user.

  A release button (not shown) is provided on the surface of the digital camera 10. When the release button is half-pressed, the photometric switch 15 connected to the microcomputer 17 is turned on. When the photometric switch 15 is turned on, the microcomputer 17 controls the AF / aperture driving mechanism 34 for autofocusing. Based on the luminance signal output from the CCD 38, the microcomputer 17 calculates an exposure value.

  Further, when the release button is fully pressed, the release switch 16 is turned on. Then, based on the calculated exposure value, the microcomputer 17 sets the aperture value of the aperture 31 to a predetermined value. Further, the AF / aperture driving mechanism 34 opens the aperture 31 by a predetermined amount corresponding to the set aperture value based on the control signal from the microcomputer 17, and the shutter (not shown) has a predetermined opening and a predetermined time. Opened. Then, the CCD 38 is exposed by reflected light from a subject incident through the photographing lens 30.

  Based on the image signal read from the CCD 38, image data is generated by the microcomputer 17 and recorded in the DRAM 42. Further, when the memory card 46 is inserted in the main body of the digital camera 10, the image data is transmitted to the memory card 46 via the interface 43 and is also recorded on the memory card 46. Note that when the image is reproduced and displayed on the LCD monitor 22 in the reproduction mode, the thinning process is performed on the image data, but the thinning process is not performed when the image data is recorded.

  When the menu button 13 is operated to display the menu item on the LCD monitor 22, the microcomputer 17 displays the menu item on the LCD monitor 22 and also sets the target exposure value set immediately before the operation of the menu button 13. Is increased by a predetermined value, for example, 8 EV. As a result, when the CCD 38 is instructed to display the menu item together with the subject image, the exposure amount of the CCD 38 is reduced to a predetermined exposure amount.

  The microcomputer 17 controls the AF / aperture driving mechanism 34 based on the newly calculated exposure value (here, the new target exposure value increased by 8 EV) to increase the aperture value of the aperture 31, and Narrow down. In this manner, the amount of light received by the CCD 38 is reduced by a predetermined amount, so that an apparently underexposed image of 8 EV is obtained. As described above, when the menu item is displayed together with the subject image, the exposure amount of the CCD 38 is reduced, so that the luminance of the displayed subject is lowered and the menu item is easily recognized.

  Here, since the brightness of the subject is sufficiently high, the aperture value of the aperture 31 reaches the maximum aperture value (the aperture value at which the aperture diameter of the aperture becomes the minimum) and cannot be further reduced to a predetermined value. There are cases where the exposure amount cannot be reduced by a predetermined amount. In this case, after the aperture value is set to the maximum aperture value by the microcomputer 17, the photographing sensitivity of the CCD 38 is reduced by an amount corresponding to the difference between the exposure value to be originally set and the maximum aperture value of the aperture 31. . As a result, a subject image that is underexposed for 8 EV is generated.

  In the shooting mode, when either the telephoto switch 27 or the wide-angle switch 28 is turned on by operating a zoom switch (not shown), a signal for telephoto or wide-angle shooting is transmitted to the microcomputer 17. Then, a signal indicating the zoom position of the photographic lens 30 which is a zoom lens is sent from the zoom encoder 32 to the microcomputer 17, and the zoom drive mechanism 26 moves the photographic lens 30 to a position where a predetermined focal length is obtained.

  FIG. 2 is a flowchart showing an image generation routine in the photographing mode. FIG. 3 is a flowchart of a menu screen control routine showing exposure control in the image generation routine.

  The image generation routine starts when the main switch 11 of the digital camera 10 is turned on. In step S101, it is determined whether or not a shooting mode is selected. If it is determined that a shooting mode is selected, the process proceeds to step S102. In step S102, the subject image is displayed on the LCD monitor 22 as a through image, and the process proceeds to step S103. In step S103, it is determined whether or not the photometric switch 15 is on. If it is determined that the photometry switch 15 is on, the process proceeds to step S104. If it is determined that the photometry switch 15 is not on, the process proceeds to step S105.

  In step S104, autofocus processing and photometry processing are performed, and the process proceeds to step S106. In step S106, it is determined whether or not the release switch 16 is on. If it is determined that the release switch 16 is on, the process proceeds to step S107. If it is determined that the release switch 16 is not on, the process proceeds to step S105.

  In step S105, it is determined whether or not there is an instruction to display the menu item on the LCD monitor 22. If there is a menu item display instruction, the process proceeds to step S108, and if there is no menu item display instruction, the process returns to step S103. In step S108, the menu screen control routine starts (see FIG. 3).

  In step S107, a still image of the subject is generated while the aperture value of the aperture 31 is adjusted based on the appropriate exposure value calculated by the microcomputer 17 and the exposure is controlled. In step S109, the generated subject image is recorded on a recording medium such as the memory card 46, and the image generation routine ends.

  On the other hand, the menu screen control routine starts when a menu item display instruction is given in step S105 in the image generation routine (see FIG. 3). In step S201, an appropriate exposure value EVP based on the luminance of the subject is calculated by the microcomputer 17, and the process proceeds to step S202. In step S202, the calculated aperture value AVM is calculated so that a value larger by 8 EV than the calculated exposure value EVP is newly set as the exposure value. That is, the microcomputer 17 calculates a value obtained by subtracting the charge accumulation time TV of the CCD 38 from the new exposure value obtained by adding 8 EV to the exposure value EVP calculated in step S201 as the calculated aperture value AVM. When the calculated aperture value AVM is calculated, the process proceeds to step S203.

In step S203, it is determined whether or not the calculated aperture value AVM is larger than the maximum aperture value AV _max of the aperture 31. When the calculated aperture value AVM is determined to be greater than the maximum aperture value AV _max proceeds to step S204, calculates the aperture value AVM is equal to the maximum aperture value AV _max, or if less than the maximum aperture value AV _max If determined, the process proceeds to step S205. In step S204, since the aperture value AV of the aperture 31 cannot be set to the calculated aperture value AVM, the aperture value AV is set to the maximum aperture value AV _max and the process proceeds to step S206.

In step S206, a calculation process for the photographing sensitivity SV of the CCD 38 is performed. That is, in order to adjust the difference between the exposure value to be set and the maximum aperture value AV _max of the aperture 31 by the imaging sensitivity SV of the CCD 38, the calculated imaging sensitivity SVM is the difference between the calculated aperture value AVM and the maximum aperture value AV _max. Is calculated as In the subsequent step S207, the microcomputer 17 reduces the output gain of the image signal from the CCD 38 by a predetermined amount so that the photographing sensitivity SV of the CCD 38 is lowered by the calculated photographing sensitivity SVM, and the process proceeds to step S208.

  On the other hand, in step S205, since the aperture value AV can be set to the calculated aperture value AVM, the calculated aperture value AVM is set as a new aperture value AV as it is, and is controlled by the aperture 31 and the AF / aperture drive mechanism 34. Aperture control is performed and control proceeds to step S208.

  In step S208, the through image of the subject whose luminance is lower than normal by aperture control or aperture control and adjustment of the photographing sensitivity of the CCD 38 is displayed on the LCD monitor 22 as a background layer, and the process proceeds to step S209. In step S209, a menu item is displayed on the LCD monitor 22 as an upper layer to be superimposed on the background layer indicating the subject image, and the process proceeds to step S210. Note that images displayed as menu items are letters, numbers, symbol marks, frame lines, and the like, and these are drawn with, for example, white letters or white lines.

  In step S210, it is determined whether or not a new parameter has been selected by the user for any of the displayed menu items. If it is determined that a new parameter has been selected, the process proceeds to step S211 and is newly selected. If it is determined that it is not, the process proceeds to step S212. In step S211, for example, any of the menu items such as recording size (image resolution), image quality, and white balance is changed according to the newly selected parameter, and the process proceeds to step S212.

  In step S212, the menu item display on the LCD monitor 22 is terminated in accordance with the user operation, and the process proceeds to step S213. In step S213, the subject image having normal brightness, that is, the aperture value corresponding to the aperture value AV calculated from the exposure value EVP instead of the calculated aperture value AVM is opened to release the aperture, and further, as necessary. The subject image obtained by increasing the photographing sensitivity from the photographing sensitivity SVM to a predetermined value is displayed on the LCD monitor 22. Then, the menu screen control routine ends, and the process returns to step S103 of the image generation routine.

  FIG. 4 is a diagram illustrating a subject image on the LCD monitor 22 in a state where no menu item is displayed. FIG. 5 is a diagram illustrating a subject image on the LCD monitor 22 displayed together with the menu items.

When the menu item is not displayed and only the subject image is displayed, the aperture value AV based on the exposure value EVP determined by the detected subject brightness is set as illustrated in FIG. A subject image having is displayed. On the other hand, when the menu item is displayed when the same subject as in FIG. 4 is displayed under the same setting conditions, the calculated aperture value AVM or the maximum aperture value AV _max larger than the aperture value AV is set, and further required. Accordingly, the photographing sensitivity SV of the CCD 38 is reduced to the calculated photographing sensitivity SVM, so that a low-luminance subject image whose exposure amount is under-stated by an amount corresponding to 8 EV is displayed (see FIG. 5).

  As illustrated in FIG. 5, the menu items include characters, numbers, symbols, and the like, and are displayed so as to be mixed with subject images including human images, mountains, seas, ships, and the like. That is, the menu items are not displayed in a specific and small number of display areas provided in the corners of the LCD monitor 22 but are unspecified and very many detailed display areas over a wide range of the LCD monitor 22. Is displayed. For this reason, when the menu item is displayed, it is preferable that the luminance of the subject is lowered so that the menu item can be easily recognized.

  As described above, according to the present embodiment, various menu items are displayed together with the subject image with reduced brightness, thereby improving the visibility of the menu items. Furthermore, the contour of the subject can be recognized even in the subject image with reduced brightness (see FIG. 5), and the subject image is not completely lost, so that the framing operation can be performed while simultaneously recognizing the menu item and the subject. become.

  FIG. 6 is a block diagram of the digital camera 10 in the second embodiment.

  The digital camera 10 of the second embodiment is different from the first embodiment in that an ND filter 35 (a neutral density filter) and an ND filter driving mechanism 37 are provided. When the brightness of the subject is extremely high in the shooting mode, the ND filter 35 is arranged on the optical path of the reflected light from the subject under the control of the microcomputer 17. As a result, the amount of light received by the CCD 38 can be reduced to an appropriate level.

  FIG. 7 is a flowchart showing a menu screen control routine in the present embodiment.

  In the present embodiment, when the brightness of the subject displayed before the operation of the menu button 13 is high and a new target exposure value cannot be realized only by adjusting the aperture value AV of the aperture 31, the photographing sensitivity SV of the CCD 38. The ND filter 35 is used without adjusting.

That is, in the menu screen control routine of this embodiment, in step S203, the calculation aperture value AVM is determined to be greater than the maximum aperture value AV _max, the maximum aperture value AV of 31 aperture AV of the diaphragm at the step S204 set _max, further in step S206, performs exposure control using the ND filter 35 with stop 31.

  As described above, according to the present embodiment, by using the ND filter 35, the luminance of the subject displayed on the LCD monitor 22 together with the menu item can be greatly reduced.

Note ND filter 35, since the amount of light decreases can not be adjusted, the use of aperture value AV of the diaphragm 31 on which is set to the maximum aperture value AV _max, object image underexposed state is generated greater than 8EV min There is a case. At this time, the menu item is easier to visually recognize than the underexposed subject image of 8 EV. On the other hand, by adjusting the aperture 31 aperture value AV when used together with the ND filter 35, the exposure value when displaying the menu item may be set to a predetermined value.

When the brightness of the subject on the normal screen is remarkably high, the aperture value AV may be set to the maximum aperture value AV _max , the ND filter 35 may be used, and the photographing sensitivity SV of the CCD 38 may be further reduced.

  In any embodiment, the difference in exposure value between the case where a normal image is displayed and the case where a subject image is displayed together with a menu item is not limited to 8 EV. Also, how much the target exposure value is increased when the menu item is displayed together with the subject image, and how much the exposure amount is reduced as a result, compared to the case where only the subject image is displayed depends on the selection of the parameter. The user may be able to set.

  In the above-described embodiment, an underexposed image is generated by controlling the aperture 31 so that the existing configuration can be used and is easy to control. However, a low-cost fixed aperture digital camera is used. In this case, only the ND filter 35 may be used.

1 is a block diagram of a digital camera according to a first embodiment. It is a flowchart which shows the image generation routine in imaging | photography mode. It is a flowchart which shows the menu screen control routine which shows exposure control in an image generation routine. It is a figure which illustrates the subject image in the state where a menu item is not displayed. It is a figure which illustrates the photographic subject image displayed with a menu item. It is a block diagram of the digital camera in 2nd Embodiment. It is a flowchart which shows the menu screen control routine in 2nd Embodiment.

Explanation of symbols

10 Digital camera 17 Microcomputer (sensitivity adjustment means / luminance detection means / exposure value setting means)
22 LCD monitor (image display means / menu item display means)
31 Aperture (light quantity adjustment means / aperture mechanism)
34 AF / aperture drive mechanism (light quantity adjustment means / aperture mechanism)
35 ND filter (light intensity adjustment means / dark filter)
38 CCD (imaging device / luminance detection means)

Claims (8)

An image sensor that receives light from a subject and generates an image signal;
A light amount adjusting means for adjusting a light amount of light received by the imaging element;
Image display means for displaying an image of the subject based on the image signal;
A menu item display means for displaying a menu item for selecting an operation content together with the image,
The exposure adjustment device, wherein when the menu item is displayed, the light amount adjusting unit reduces the amount of light received by the image sensor as compared with when the menu item is not displayed. It further has sensitivity adjustment means for adjusting the sensitivity of the image sensor,
The exposure adjustment apparatus according to claim 1, wherein when the menu item is displayed, the sensitivity adjustment unit lowers the sensitivity of the image sensor than when the menu item is not displayed.   The exposure adjusting apparatus according to claim 1, wherein the light amount adjusting unit includes at least one of a diaphragm mechanism and a neutral density filter. Luminance detection means for detecting the luminance of the subject;
Exposure value setting means for setting a target exposure value of the image sensor based on the luminance of the subject;
When the menu item is displayed, the exposure value setting means sets the target exposure value that is larger than when the menu item is not displayed, and the light amount adjusting means is configured to capture the image based on the target exposure value. The exposure adjusting apparatus according to claim 1, wherein the exposure amount of the element is reduced.   5. The exposure adjustment according to claim 4, wherein the exposure value setting means sets the target exposure value that is larger by a predetermined value when the menu item is displayed than when the menu item is not displayed. apparatus.   The exposure adjustment apparatus according to claim 4, wherein the exposure value setting unit can set the target exposure value designated by a user.   The exposure adjusting apparatus according to claim 1, wherein the image display unit displays the image as a through image. An image sensor that receives light from a subject and generates an image;
Image display means for displaying an image of the subject based on the image signal;
Sensitivity adjusting means for adjusting the sensitivity of the image sensor;
A menu item display means for displaying a menu item for selecting an operation content together with the image,
When the menu item is displayed, the sensitivity adjustment unit lowers the exposure amount of the image sensor by lowering the sensitivity of the image sensor than when the menu item is not displayed. Adjustment device.

Images