JP4173459B2 - Digital camera - Google Patents

Description

  The present invention relates to a digital camera having a self-timer shooting mode for recording image data based on an imaging signal obtained from an imaging device after a lapse of a certain time from a shutter release operation.

  Recent photographic cameras and digital cameras are generally provided with a self-timer shooting mode in which shooting is performed after a certain period of time has elapsed since the shutter release operation so that a photographer can enter a shooting frame as a subject. When shooting with this self-timer shooting mode set, the subject (person) is not in the center of the shooting frame or there is a gap between the two subjects (person) as in normal shooting. In some cases, so-called hollows may occur where the focus of the photographic lens matches the background. As a method of preventing such omission during self-timer shooting, multipoint ranging is performed immediately after the shutter release operation to identify the state of the subject, so-called shooting scene, and the distance measurement target is determined according to the shooting scene. A method has been devised to identify the subject.

  In the method described in Patent Document 1, immediately after the shutter release operation, three-point distance measurement of the left and right and center of the photographing frame is performed, and the subject distance in three directions is measured. Then, the measured left and right subject distances are compared, and if this distance difference is larger than a preset distance difference, the shooting scene is identified as a hollow scene where a hollow gap is likely to occur. For a subject image identified as a hollow scene, three-point distance measurement is performed again after waiting for a fixed time, and subject distances in three directions are measured. The subject at the closest distance among the subject distances in the three directions is set as a distance measurement target. Shooting is performed after focusing on the set subject is completed. On the other hand, for a subject image identified as a non-missing scene, after waiting for a certain time, focusing is performed on the subject closest to the subject distance in the three directions immediately after the shutter release operation, Shooting is performed.

JP-A-10-293342

  As described above, in the method of specifying a distance measurement target based on the subject distance by multi-point distance measurement, if any subject distance is measured incorrectly, the shooting scene cannot be accurately identified and appropriate distance measurement is possible. The target is not set. As a result, the photographed subject image is lost without correct focusing.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a digital camera having a self-timer shooting mode that prevents a shooting failure due to a void.

In order to achieve the above object, the digital camera of the present invention performs a predetermined delay process after the shutter release operation, and records the image data of the subject based on the imaging signal obtained from the image sensor after the delay process. A digital camera having a self-timer shooting mode, and monitors an imaging signal obtained from a predetermined area of an image sensor set in response to a shutter release operation in the self-timer shooting mode, and detects an increase in skin color component. Monitoring means for outputting a start signal, a timer for timing a predetermined time in response to the output of the start signal, and after the timer has timed a predetermined time, based on the image pickup signal from the predetermined area, Autofocus means for focusing, and after focusing by the autofocus means is completed, Recording control means for recording image data of a subject based on an imaging signal from the imaging device, and an electronic viewfinder for displaying a through image of the subject and a monitoring frame corresponding to the predetermined area based on the imaging signal from the imaging device The position and size of the predetermined area can be changed according to the setting operation of the photographer, and the display position and size of the monitoring frame in the electronic viewfinder can be changed according to the change of the position and size of the predetermined area. Be changed.

In the invention according to claim 2, the monitoring means extracts a pixel having a hue value representing the skin color of a person from each pixel of image data based on an imaging signal obtained from a predetermined area, and extracts the extracted pixels. While obtaining the area, an activation signal is output when an increase in the skin color component is detected when the obtained area is equal to or greater than a predetermined value.

According to a third aspect of the present invention, when the focusing of the photographic lens is not completed within a predetermined time, the autofocus means moves the photographic lens to the pan focus position and completes the focusing.

According to a fourth aspect of the present invention, an auto bracketing function is provided, and when a single shutter release operation is performed, the recording control means changes the exposure in stages and captures images for a plurality of screens. Record image data sequentially. The invention described in claim 5 has a portrait function. According to a sixth aspect of the present invention, the recording control unit has a night view function, and when a shutter release operation is performed once, the recording control unit changes the exposure in stages and captures image data for a plurality of screens. Are sequentially recorded, and a strobe that emits strobe light to a person as a subject emits constant strobe light when each image data is captured.

  According to the present invention, when an increase in the skin color component is detected with respect to an image signal from a predetermined area of the image sensor preset by the photographer, the image signal from the predetermined area of the image sensor is waited for a predetermined time. Since the subject image data is recorded based on the imaging signal from the image sensor after this focusing is completed, the photographer himself is surely focused and fails. Can be taken.

  When the shutter release operation is performed once when the auto bracketing function is set, the exposure is changed in stages to capture multiple screens, and these are recorded in sequence, so multiple images with the same composition are discarded. It is possible to select, and it is possible to prevent imaging from failing due to unconfirmation of the subject image at the time of imaging.

  FIG. 1 shows the electrical configuration of a digital camera 10 embodying the present invention. The system controller 11 controls each part of the main body of the digital camera 10 in accordance with an operation signal input from the operation unit 14. The ROM 12 stores a control program executed by the system controller 11. The RAM 13 is a working memory when the system controller 11 executes a control program.

  The operation unit 14 includes a power button, a release button, a mode switching dial, a cross key, a cancel button, a menu button, and the like. The release button is configured in a two-stage press type. When the release button is lightly pressed and the first stage is turned on, the autofocus (AF) mechanism and the automatic exposure (AE) mechanism are operated, and focusing and exposure setting are performed. Next, when the release button is further pushed in, the second stage is turned on, and the shutter release is performed.

  The mode switching dial switches the operation mode of the digital camera 10. The operation modes include a shooting mode for shooting an image, a playback mode for playing back and displaying the shot image on an LCD (Liquid Crystal display) 16, and various operation modes such as a setup mode for performing various settings.

  The LCD 16 displays a playback image in the playback mode and also functions as an electronic viewfinder by displaying a through image for subject confirmation in the shooting mode. In the setup mode, a setting screen for performing various settings is displayed. The cross key is used to select a setting item by moving the cursor in the setting screen.

  The menu button can select a plurality of shooting modes according to the shooting scene. Multiple shooting modes include AF mode for switching AF settings such as central AF and multi-point AF, strobe mode for switching strobe settings according to shooting conditions, and shooting after a predetermined delay process after shutter release operation There is a self-timer shooting mode. In each of these shooting modes, shooting is performed based on shooting conditions set in advance for each mode.

  A self-timer circuit 17 is connected to the system controller 11. The self-timer circuit 17 measures time in response to a timing start signal output from a skin color detection circuit 35 described later. When the time measurement is completed, the self-timer circuit 17 sends a time measurement completion signal to the system controller 11. In response to the timing completion signal, the system controller 11 executes an imaging process for recording the image data of the subject based on the imaging signal obtained from the CCD image sensor 24.

  The photographing lens includes a zoom lens 18 and a focus lens 19. A diaphragm 20 is disposed between the zoom lens 18 and the focus lens 19. The zoom lens 18 and the focus lens 19 are moved along the optical axis direction by a zoom motor 21 and a focus motor 22 having a driver circuit. The diaphragm 20 is driven by an actuator 23 having a driver circuit.

  A CCD image sensor 24 is disposed behind the focus lens 19. As is well known, the CCD image sensor 24 has a photocathode formed by arranging a large number of light receiving elements in a matrix, and photoelectrically converts subject light imaged on the photocathode.

  The CCD image sensor 24 is driven by a CCD driver 25. The charge accumulation time (exposure time) of the CCD image sensor 24 is determined according to the electronic shutter drive signal supplied from the CCD driver 25. Then, in synchronization with the vertical transfer clock and the horizontal transfer clock supplied from the CCD driver 25, the charges accumulated for each pixel are output as a serial imaging signal line by line.

  The image pickup signal output from the CCD image sensor 24 is input to the A / D converter 27 after noise is removed by the correlated double sampling process and amplified by the amplifier 26. The A / D converter 27 digitally converts the imaging signal to generate image data, which is sequentially input to the image data processing circuit 28.

  The image data processing circuit 28 performs various kinds of image processing such as matrix calculation processing, white balance adjustment, and gamma correction on the input image data. Image processed image data is temporarily stored in the frame memory 29. The image data stored in the frame memory 29 is displayed on the LCD 16 as a through image.

  When the imaging process is executed, the stored image data in the frame memory 29 is sent to the compression / decompression circuit 30. The compression / decompression circuit 30 performs a compression process on the image data and outputs it to the read / write circuit 31. The read / write circuit 31 writes the compressed image file to the memory card 32. In the reproduction mode, after the read / write circuit 31 reads an image file from the memory card 32, the decompression process is performed by the compression / decompression circuit 30 and the result is output to the LCD 16.

  The AF circuit 33 detects the focal length based on the image data corresponding to the distance measurement area in the frame memory 29. As the focal length detection method, for example, a passive method is used that detects the focal length by utilizing the feature that the contrast of the image is high in a focused state.

  The AE circuit 34 measures the subject brightness based on the image data corresponding to the photometric area in the frame memory 29, and calculates the aperture value, the exposure time, and the exposure condition for determining whether or not to emit a strobe (not shown) from the photometric value. Ask for. An auto white balance (AWB) circuit 34 automatically adjusts the white balance during imaging.

  Imaging conditions such as a focal length, an aperture value, and an exposure time obtained by the AF circuit 33 and the AE / AWB circuit 34 are written into the RAM 13 by the system controller 11 and set as imaging conditions when executing the imaging process. The system controller 11 operates each unit based on the set shooting condition, and executes an imaging process.

  In the self-timer shooting mode, the digital camera 10 includes means for setting a distance measurement area and monitoring means for monitoring image data corresponding to the set distance measurement area and detecting an increase in the skin color component. The self-timer shooting mode is normally used for the photographer himself to enter the shooting frame as a subject. Before the shutter release operation, the photographer sets the area into which he / she enters in the photographing frame as a distance measurement area. Then, by entering the set distance measurement area as a subject, the subject himself / herself is set as a distance measurement target.

  FIG. 2 shows a shooting scene in which the subject person is only the photographer P1. An actual distance measurement area setting procedure will be described with reference to FIG. When the self-timer shooting mode is selected by operating the menu button, a monitoring frame 41 (dotted line in the figure) representing the distance measuring area is displayed at the center of the LCD 16 displaying the through image 40 (FIG. 2A). State shown in). The position of the monitoring frame 41 (ranging area) can be changed by operating the cross key. The photographer moves the monitoring frame 41 to a desired position, for example, the lower right in the figure, and sets a distance measurement area. The size of the monitoring frame 41 can be freely changed by a photographer's setting operation.

  FIG. 3 shows a shooting scene in which there are three persons as subjects, including the photographer P1. As described above, when the shooting frames are crowded, the size of the monitoring frame 41 is reduced and the monitoring frame 41 is appropriately arranged.

  When the shutter release operation is performed after setting the distance measurement area, the image data processed image data is input from the image data processing circuit 28 to the skin color detection circuit 35 at regular intervals. The skin color detection circuit 35 as monitoring means monitors the image data corresponding to the monitoring frame 41 of the input image data. When the skin color detection circuit 35 detects an increase in the skin color component in the image data to be monitored, the skin color detection circuit 35 sends a time measurement start signal to the system controller 11. As a method for detecting an increase in the skin color component, a pixel having a hue value representing the skin color of a person is extracted from each pixel of the image data, and the area of the extracted pixel is obtained. If this area is equal to or larger than the predetermined area, it is determined that the photographer P1 has entered the monitoring frame 41 (ranging area) (the state shown in FIGS. 2B and 3B), and the self-timer A timing start signal for starting the timing of the circuit 17 is sent to the system controller 11.

  In the present embodiment, when the focal length detection by the AF circuit 33 is not completed within a predetermined time in the self-timer photographing mode, the fixed focus pan focus is set. As a result, even when the photographer P1 is out of the distance measurement area and cannot perform focusing correctly, focusing is performed so as not to cause a void, and imaging processing is executed.

  In the present embodiment, in the self-timer shooting mode, it is possible to set auto bracketing shooting in which continuous shooting is performed by changing the exposure stepwise. A setting procedure for auto bracketing shooting in the self-timer shooting mode will be described. As shown in FIG. 4A, the LCD 16 has menus such as “AF mode”, “strobe mode”, and “self-timer”, and a selection frame 50 that functions as a cursor for selecting each menu. Is displayed. The selection frame 50 is moved by operating the cross key, and the menu can be selected by stopping the selection frame 50 at a desired position and pressing a menu button.

  When “Self-timer” is selected, the display on the LCD 16 is switched as shown in FIG. 4B, and a menu such as “Auto bracketing shooting on” and “Auto bracketing shooting off” is selected. A frame 51 is displayed. By moving the selection frame 51 with the cross key and pressing the menu button, it is possible to switch on / off auto bracketing shooting in the self-timer shooting mode.

  In auto bracketing shooting in the self-timer shooting mode, when one shutter release operation is performed, the exposure (aperture value, exposure time) is changed to, for example, three stages, and imaging processing for three frames is executed. The amount of exposure shift and the number of shots can be set by the photographer.

  A procedure for imaging processing for three frames will be described. First, an image pickup signal is acquired by the CCD image sensor 24 at an appropriate exposure (reference exposure: E = 0) corresponding to the shooting situation. Image data generated by digitally converting the imaging signal is recorded in the memory card 32 after being subjected to various image processing. Next, from the proper exposure, the exposure is increased by the amount of shift set by the photographer (over: E = + α), and an imaging signal is acquired. The image data obtained from the image pickup signal is also subjected to image processing and recorded in the memory card 32 as in the case of proper exposure. Finally, the exposure is lowered by the same shift amount from the appropriate exposure (under: E = −α), and an image pickup signal is acquired. Similarly, image data obtained from the imaging signal is subjected to image processing and recorded in the memory card 32. When the imaging process for three frames is completed in this manner, a self-timer lamp (not shown) that has been continuously turned on after the shutter release operation is turned off, indicating the completion of auto bracketing shooting.

  When the mode switching dial is set to the playback mode, as shown in FIG. 5, the LCD 16 displays three screens 60a, 60b, and 60c having the same composition and different exposures. In addition, the images 60a, 60b, and 60c are displayed with characters indicating the exposure stage such as “standard”, “over”, and “under” together with the file name, thereby facilitating identification. The photographer can compare the three images and leave all the image data or delete them. Also, any image data can be selected and left, and other image data can be deleted.

  The function of auto bracketing shooting in the self-timer shooting mode will be described below with reference to the flowchart of FIG. The photographer first displays a through image on the LCD 16 and operates the cross key to set an area (ranging area) in which the photographer enters (FIG. 2A). When the release button is completely pressed after setting the distance measurement area, image data is input from the image processing circuit 28 to the skin color detection circuit 35 at regular intervals. The skin color detection circuit 35 monitors the image data corresponding to the distance measurement area of the input image data. When the photographer enters the distance measurement area (FIG. 2B) and the skin color detection circuit 35 detects an increase in the skin color component, a time measurement start signal is sent to the system controller 11.

  In response to the timing start signal, the system controller 11 activates the self-timer circuit 17 to measure a certain time. When the time measurement for a certain time is completed, the AF circuit 33 and the AE / AWB circuit 34 obtain imaging conditions such as a focal length, an aperture value, and an exposure time. The AF circuit 33 detects the focal length based on the image data corresponding to the distance measurement area. If this focal length detection is not completed within a predetermined time, pan focus is set.

  When all the imaging conditions are obtained, the system controller 11 executes an imaging process based on the imaging conditions. In this imaging process, image data for three frames with the same composition and exposure changed in three stages is recorded in the memory card 32. When the mode switching dial is set to the reproduction mode, these three images 60a, 60b and 60c are displayed on the LCD 16 (FIG. 5).

  In the above embodiment, the increase in the skin color component and the detection of the focal position are detected based on the image processed image data corresponding to the distance measurement area, but the image processed image data is always used. There is no need, and an imaging signal obtained from the CCD image sensor 24 may be used directly.

  In the above embodiment, the hue value of each pixel of the image data is used as a comparison element when detecting an increase in the skin color component, but the comparison element is not limited to the hue value. For example, the subject brightness measured by the AE circuit 34 may be used.

  In the above embodiment, the imaging process is not executed unless an increase in the skin color component is detected, but the imaging process may be forcibly executed. For example, after a certain time has elapsed since the release button was pressed, the flesh color component is detected only once for image data in a predetermined area. When an increase in the skin color component is detected, the focal length based on the predetermined area is detected, and imaging processing is executed. On the other hand, if an increase in the skin color component is not detected, pan focus is set and imaging processing is executed.

  In the above embodiment, no time restriction is provided in the detection of the skin color component, but a time restriction that can be set by the photographer may be provided. In this case, if an increase in the skin color component is not detected within a predetermined time, the subsequent processing may be prohibited, or panning focus may be set and the imaging processing may be executed.

  In the above embodiment, auto bracketing shooting can be set in the self-timer shooting mode, but in addition to this auto bracketing shooting, a portrait mode suitable for portrait shooting and a night view mode suitable for night scene shooting can be set. And

  When the portrait mode is set, the imaging condition is set so that the person who is the subject is more conspicuous and the background is blurred. In the image processing, skin color correction is focused on so that the skin color looks beautiful.

  Also, when the night view mode is set, as with auto bracketing shooting, when a single shutter release operation is performed, the exposure is changed in stages to capture multiple frames. Execute. As the imaging condition when the night view mode is set, the strobe is set so that a constant strobe light is emitted to the person who is the subject.

It is a block diagram which shows the structure of a digital camera. It is explanatory drawing of the ranging area in the imaging | photography scene where the person who becomes a subject is one person. It is explanatory drawing of the ranging area in the imaging | photography scene where the person who becomes a subject is three persons. It is explanatory drawing of the display content of LCD at the time of setting auto bracketing imaging | photography in self-timer imaging | photography mode. It is explanatory drawing of the display content of LCD which reproduced and displayed the image obtained by the auto bracketing imaging | photography in self-timer imaging | photography mode. It is a flowchart of auto bracketing shooting in the self-timer shooting mode.

Explanation of symbols

10 Digital Camera 11 System Controller 14 Operation Unit 16 LCD
17 Self-timer circuit 24 CCD image sensor 33 AF circuit 35 Skin color detection circuit

Claims (6)

In a digital camera having a self-timer shooting mode for performing predetermined delay processing after a shutter release operation and recording image data of a subject based on an imaging signal obtained from the imaging device after the delay processing,
Monitoring means for monitoring an imaging signal obtained from a predetermined area of the imaging element set in advance in response to a shutter release operation in the self-timer imaging mode, detecting an increase in the skin color component, and outputting an activation signal;
A timer for measuring a predetermined time in response to the output of the start signal;
Auto focus means for focusing the photographic lens based on an imaging signal from the predetermined area after the timer counts a predetermined time ;
Recording control means for recording image data of a subject based on an image pickup signal from the image pickup device after focusing by the autofocus means is completed ;
An electronic viewfinder for displaying a through image of a subject and a monitoring frame corresponding to the predetermined area based on an imaging signal from an imaging device ;
The position and size of the predetermined area can be changed according to the setting operation of the photographer, and the display position and size of the monitoring frame in the electronic viewfinder can be changed according to the change of the position and size of the predetermined area. A digital camera characterized by The monitoring means extracts a pixel having a hue value representing a person's skin color from each pixel of image data based on an imaging signal obtained from a predetermined area, obtains an area of the extracted pixel, and the obtained area is 2. The digital camera according to claim 1, wherein an activation signal is output when an increase in the skin color component is detected when the value is equal to or greater than a predetermined value. The autofocus unit, when is not completed focusing of the taking lens within a predetermined time period, according to claim 1 or 2 digital camera according to, characterized in that to complete the move by focusing a taking lens to the pan-focus position. It has an auto bracketing function, and when a shutter release operation is performed once, the recording control means sequentially records image data for a plurality of screens obtained by changing the exposure stepwise. The digital camera according to any one of claims 1 to 3 . The digital camera according to claim 1, further comprising a portrait function. With a night view function, when a shutter release operation is performed once, the recording control means sequentially records image data for a plurality of screens obtained by changing the exposure stepwise to become a subject. 6. The digital camera according to claim 1, wherein a strobe that emits strobe light to a person emits constant strobe light when each image data is captured.

Images