JP4798292B2 - Electronic camera - Google Patents

Description

The present invention relates to an electronic still camera that can perform high-speed continuous shooting with high image quality.

The image signal only read out Succoth the partial region of the image sensor during continuous the normal photographing reading image signals from the entire area of the imaging element, while maintaining high image quality in normal imaging and high-speed continuous shooting an electronic camera which is adapted obtain line is known (for example, Patent Document 1).
Also, for single, continuous, multi-continuous, and high-speed continuous shooting that reads image data from all pixels of the image sensor, high-speed reading that reads image data from only some pixels of the image sensor during ultra-high-speed continuous shooting In other words, there is known a camera that performs ultra-high-speed continuous shooting by performing a so-called thinning-out reading to shorten the time for reading image data from the image sensor (for example, Patent Document 2).

Prior art documents related to the invention of this application include the following.
Japanese Patent Laid-Open No. 08-037634 JP 2001-94855 A

However, when the technique of the electronic camera disclosed in Patent Document 2 is applied to the electronic camera disclosed in Patent Document 1 in which the continuous shooting speed is constant to enable shooting at a plurality of continuous shooting speeds , a fixed readout area is provided in the image sensor. This is configured to read only the image signal in this fixed readout area during continuous shooting, so if the number of shot frames per second during continuous shooting is small, a high-quality image can be obtained, but the number of frames is When there are many, there exists a problem that an image quality worsens.

(1) An electronic camera according to a first aspect of the present invention is an image pickup device capable of picking up a subject image and reading an image in an arbitrary region of the picked-up image, a speed setting operation member for setting a continuous shooting speed, Detecting means for detecting the position of the main subject in the image read from the image sensor by subject recognition processing, and the maximum image that can be read from the image sensor at the continuous shooting speed set by the speed setting operation member Area calculating means for automatically setting a reading area; and image reading means for reading a captured image of the image reading area set by the area calculating means at a continuous shooting speed set by the speed setting operation member from the image sensor during continuous shooting. The area calculation means sets the image readout area at the center of the captured image during continuous shooting, and the position of the main subject detected by the detection means When protruding from the image reading area is to set to the image reading area is the main subject are not exposed.
(2) In the electronic camera according to the second aspect, the frame indicating the image reading area set by the area calculating means is displayed superimposed on the finder image before starting continuous shooting.
(3) The electronic camera according to claim 3 displays only the captured image in the image reading area set by the area calculation means on the finder before starting the continuous shooting.
(4) According to a fourth aspect of the present invention, there is provided an electronic camera that captures an image of a subject and reads an image in an arbitrary area of the captured image, and an image captured from the images captured by the image sensor. The area that can be read from the image reading area set by the area setting operation member that sets the area from among a plurality of image reading areas having different sizes and the area setting operation member that is captured by the image sensor. Speed calculating means for automatically setting the continuous shooting speed, and image reading means for reading the captured image at the continuous shooting speed set by the speed calculating means from the image reading area set by the area setting operation member of the image sensor during continuous shooting With.
(5) The electronic camera according to claim 5 includes speed display means for displaying the continuous photographing speed set by the speed calculation means on the viewfinder.
(6) The electronic camera according to claim 6 is provided with a region display unit that superimposes and displays a frame indicating the image readout region set by the region setting operation member on the finder image before starting continuous shooting.
(7) The electronic camera according to claim 7 includes a finder display control unit that displays only a captured image in the image reading area set by the area setting operation member on the finder before starting continuous shooting.
(8) An electronic camera according to an eighth aspect of the present invention is an image pickup device capable of picking up a subject image and reading an image in an arbitrary region of the picked-up image, a speed setting operation member for setting a continuous shooting speed, Detecting means for detecting the position of the main subject in the image read from the image sensor and the maximum image reading area where the captured image can be read from the image sensor at the continuous shooting speed set by the speed setting operation member is automatically set Area calculating means for automatically setting, and image reading means for reading the captured image of the image reading area set by the area calculating means at the continuous shooting speed set by the speed setting operation member from the image sensor during continuous shooting. The area calculation means sets the image reading area based on the position of the main subject detected by the detection means.

(1) According to the first aspect of the present invention, the maximum image reading area according to the set continuous shooting speed can be automatically set, and high-speed continuous shooting of a wide area image is performed while maintaining high image quality. be able to.
(2) According to the invention of claim 4, it is possible to automatically set the maximum continuous shooting speed according to the set image reading area, and to continuously shoot a wide area image at a high speed while maintaining high image quality. be able to.
(3) According to the invention of claim 8, it is possible to arbitrarily select whether to give priority to the continuous shooting speed or to give priority to the image reading area.

It is the front perspective view (a) and back perspective view (b) of the digital camera of 1st Embodiment. It is a figure which shows the structure of the digital camera of 1st Embodiment. It is a figure which shows the finder screen at the time of the continuous imaging | photography of 1st Embodiment. It is a figure which shows the other example of a finder screen at the time of the continuous imaging | photography of 1st Embodiment. It is a flowchart which shows the process at the time of the continuous imaging | photography of 1st Embodiment. It is a flowchart which shows the process at the time of the continuous imaging | photography of 2nd Embodiment.

<< First Embodiment of the Invention >>
FIG. 1 is a front perspective view (a) and a rear perspective view (b) of the digital camera according to the first embodiment. In the digital camera of the first embodiment, a photographic lens barrel 2 is attached to a camera body 1. In the first embodiment, a single-lens reflex digital camera in which a photographic lens barrel is attached to the camera body will be described as an example. However, for a so-called compact digital camera in which the photographic lens is built in the camera body. However, the present invention can be applied.

  On the upper surface of the camera body 1, a shutter release button 3, a liquid crystal display 4, a mode dial 5, a subcommand dial 6, and the like are provided. A main command dial 7, a multi selector 8, a liquid crystal monitor 9, a menu button 10, and the like are provided on the back of the camera body 1.

  The liquid crystal display 4 on the upper surface of the camera body has a remaining battery level, shutter speed (1/125) or ISO (imaging sensitivity), aperture (F5.6), shooting mode (M), QUAL (image quality, FINE), white balance. Display segments such as (WB), AF area, number of shots (35), and exposure correction value are provided.

  In addition to the program shooting mode P, shutter speed priority shooting mode S, aperture priority shooting mode A, and manual shooting mode M, the mode dial 5 is an ISO (imaging sensitivity) setting mode that is frequently operated during shooting, WB (white) This is a dial type operation member for selecting a (balance) setting mode and a QUAL (image quality) setting mode. The sub-command dial 6 and the main command dial 7 are dial-type operation members for setting information relating to shooting such as an exposure value, a continuous shooting speed (the number of frames per second), and an image reading area.

  The multi-selector 8 is composed of up / down / left / right push button type direction keys, and moves the cursor up / down / left / right on the menu screen of the liquid crystal monitor 9. The menu includes white balance, metering method, continuous shooting, image reading area during continuous shooting, ISO, contour enhancement, gradation correction, and the like, which are selected with the up / down direction key of the multi selector 8 and set with the left / right direction key. The menu button 10 is a switch for displaying various information setting items and information menu screens on the liquid crystal monitor 9.

  FIG. 2 shows the configuration of the digital camera according to the first embodiment. The image pickup device 11 is an image pickup device such as a CMOS that picks up a subject image formed by a photographing lens (not shown), and outputs an analog image signal of the subject image. This image sensor can read out only an image in an arbitrarily set area among the captured images. The input circuit 12 performs processing such as change of imaging sensitivity (gain adjustment) on the analog image signal from the image sensor 11, and then performs A / D conversion to obtain the set number of recording pixels (image size). Image processing such as change, gradation correction (gamma correction), edge enhancement, and white balance adjustment is performed and output as original image data. The compression / decompression circuit 13 compresses the original image data according to the set compression rate (image quality mode), and decompresses the compressed image data to the original image data. The distance measuring device 14 detects the shooting distance to the subject. The photographing lens is driven to focus by the lens driving device 15 according to the distance measurement result.

  The shutter button switch 3a outputs a signal corresponding to the operation of the shutter button 3. The mode dial switch 5a outputs a signal corresponding to the setting position (setting mode) of the mode dial 5. The main command dial switch 7a outputs a signal for each click of the main command dial 7 in the right direction and left direction, and the sub command dial switch 6a has one of the right direction and left direction rotation of the sub command dial 6. Output a signal for each click. The multi selector switch 8a outputs a signal corresponding to each direction key when the up / down / left / right push button type direction keys of the multi selector 8 are operated. The menu button switch 10a outputs a signal when the menu button 10 is operated.

The lens driving device 15 drives the photographing lens in accordance with the distance measurement result of the distance measuring device 14.
The buffer memory 16 is a memory that temporarily stores original image data after photographing and compressed image data after compression, and SRAM, VRAM, SDRAM, or the like can be used. The monitor image generation circuit 17 generates display image data from the original image data captured by the image sensor 1 when the shooting mode is set and displays it on the liquid crystal monitor 9, and the compressed image data read from the memory card 19 when the playback mode is set. Is decompressed by the compression / decompression circuit 13, and display image data is generated and displayed by the monitor image generation circuit 17. The display driving circuit 18 drives each display segment of the liquid crystal display 4 to display various information. The memory card 19 is a removable image recording medium, and a flash memory or the like can be used.

  The controller 20 is composed of peripheral components such as a CPU 20a and a memory 20b, and performs various calculations and sequence control of the digital camera and performs continuous shooting processing described later. The display driving circuit 21 drives the finder display 22 and displays a frame (details will be described later) indicating an image reading area during continuous shooting (continuous shooting) in addition to the shooting mode, exposure value, number of shot frames, and the like.

  Here, the number of frames taken per second during continuous shooting according to the first embodiment (referred to as continuous shooting speed or continuous shooting speed in this specification) and the readout area of the image signal from the image sensor 11 (this specification). Now, the relationship with the image reading area will be described. In the first embodiment, an image reading area is set according to the continuous shooting speed, and both high image quality and high-speed continuous shooting are achieved. In other words, the higher the continuous shooting speed, that is, the greater the number of continuous shooting frames per second, the narrower the image readout area and the high-speed continuous shooting is realized without degrading the image quality.

  3 and 4 are views showing a finder screen at the time of continuous shooting according to the first embodiment. In the first embodiment, it is assumed that image signals can be read from the entire area of the image sensor 11 until the continuous shooting speed is 3 frames / second. When the continuous shooting speed is up to 3 frames / second, the frame indicating the image reading area is not displayed on the finder display 22 as shown in FIG. 3A, and the entire area of the subject image is displayed on the entire finder screen. To do. Therefore, the photographer can recognize that the entire area of the captured image is read out.

  When the continuous shooting speed exceeds 4 frames / second, the image signal cannot be read from the entire area of the image sensor 11, and therefore the image reading area of the image sensor 11 is limited according to the continuous shooting speed. FIG. 3B shows an image display example of the finder display 22 when the continuous shooting speed is 5 frames / second. In this case, the maximum image reading area that can be read out at a continuous shooting speed of 5 frames / second is calculated while maintaining the same image quality as when the continuous shooting speed is up to 3 frames / second, and continuous shooting is started. A frame 23a indicating an image reading area is superimposed on the subject image before being displayed. Thereby, the photographer can recognize that only the image within the frame 23a of the captured image can be read out at the continuous shooting speed of 5 frames / second. In this case, only the subject image within the readout area may be displayed on the finder display 22 as shown in FIG. This can be realized by driving a liquid crystal panel arranged on the surface of the finder display 22 by the display driving circuit 21 so that an image outside the image reading area cannot be transmitted. Similarly, the monitor 9 may be driven by the monitor image generation circuit 17 and only the captured image in the image reading area may be displayed on the monitor 9 before starting continuous shooting.

FIG. 3C shows an example of image display on the finder display 22 when the continuous shooting speed is 10 frames / second. In this case, while maintaining the same image quality as when the continuous shooting speed is up to 3 frames / second, the maximum image reading area that can be read at a continuous shooting speed of 10 frames / second is calculated, and continuous shooting is started. A frame 23b indicating an image readout area is superimposed on the subject image before display. Thereby, the photographer can recognize that only the image within the frame 23b of the captured image can be read out at the continuous shooting speed of 10 frames / second. In this case, only the subject image within the image reading area may be displayed on the finder display 22 and the monitor 9 as shown in FIG.

  In the example shown in FIGS. 3A to 3C described above, when the continuous shooting speed increases (when the number of continuous shooting frames per second increases), the image reading area is set at the center of the captured image. However, the main subject is not always present at the center of the captured image, and in such a case, the main subject may fall out of the image readout area as the continuous shooting speed increases. Further, even if the main subject is at the center of the captured image, a part of the main subject may protrude from the image reading area as shown in FIG. In order to prevent such a problem, the position of the main subject in the captured image is detected using a known face recognition method or subject recognition method, as shown in FIGS. 3 (d) and 4 (c). It is desirable to set the image readout area so that the main subject does not protrude from the image readout area.

  The continuous shooting speed, that is, the number of continuous shooting frames per second is selected by selecting the continuous shooting (continuous shooting) mode from the menu displayed on the monitor 9 by the operation of the menu button 10 and using the main command dial 7. Set.

  FIG. 5 is a flowchart showing processing at the time of continuous shooting according to the first embodiment. The operation of the first embodiment will be described with reference to this flowchart. The microcomputer 20a of the controller 20 executes this process when the continuous shooting mode is selected on the menu screen.

  In step 1, the continuous shooting speed set by the main command dial 7, that is, the number of continuous shooting frames per second is read. In subsequent step 2, it is confirmed whether or not all the pixels of the image sensor 11 can be read out at the set continuous shooting speed. If the entire area of the image captured by the image sensor 11 cannot be read at the set continuous shooting speed, the process proceeds to step 3 to calculate an area readable from the image captured by the image sensor 11 at the set continuous shooting speed. In step 4, the display drive circuit 21 is controlled to display a frame indicating the read area of the captured image on the subject image of the finder display 22. On the other hand, if the entire area of the image captured by the image sensor 11 can be read at the set continuous shooting speed, the process proceeds to step 5.

  In step 5, it is confirmed whether or not the shutter button 5 has been operated by the shutter button switch 5 a, and when the shutter is released, the process proceeds to step 6, and imaging is performed by the image sensor 11. In subsequent step 7, the image signal is read out from the pixels in the reading area in the picked-up image of the image pickup device 11 by the input circuit 12 and stored in the buffer memory 16. In step 8, the original image is read from the buffer memory 16, the image is compressed by the compression / decompression circuit 13 according to the preset image quality and file size, and the compressed image is stored again in the buffer memory 16.

  In step 10, it is confirmed whether or not the shutter button 5 remains operated by the shutter button switch 5a. If the shutter button 5 remains operated, the process returns to step 6 to continue the continuous shooting process as described above. If the button 5 is released, the continuous shooting process is terminated and the routine proceeds to step 11. In step 11, the compressed image stored in the buffer memory 16 is transferred to the memory card 19 and recorded, and the continuous shooting process is terminated.

  As described above, according to the first embodiment, the maximum image reading area where the captured image can be read from the image sensor 11 at the set continuous shooting speed is calculated, and the set continuous shooting is performed from the image sensor 11 during continuous shooting. Since the captured image of the maximum image readout area is read at high speed, the maximum image readout area can be automatically set according to the set continuous shooting speed, and a wide area image can be maintained while maintaining high image quality. High-speed continuous shooting.

  In addition, according to the first embodiment, the frame indicating the calculated maximum image readout area is displayed superimposed on the viewfinder image before starting continuous shooting, so it is set on the viewfinder. An image reading area corresponding to the continuous shooting speed can be confirmed.

  Furthermore, according to the first embodiment, since only the captured image within the maximum image readout area of the calculation result is displayed on the finder before starting continuous shooting, the set continuous shooting speed is displayed on the finder. The read image during continuous shooting can be confirmed.

<< Second Embodiment of the Invention >>
In the first embodiment described above, the example in which the image reading area is set according to the continuous shooting speed has been described. However, the second embodiment in which the continuous shooting speed is set according to the read area of the captured image will be described. . The configuration of the second embodiment is the same as the configuration shown in FIGS. 1 and 2, and a description thereof will be omitted.

  FIG. 6 is a flowchart showing processing at the time of continuous shooting according to the second embodiment. The operation of the second embodiment will be described with reference to this flowchart. The microcomputer 20a of the controller 20 executes this process when the continuous shooting mode is selected on the menu screen. Note that steps that perform the same processing as the processing shown in FIG. 5 are given the same step numbers, and the differences will be mainly described.

  In step 21, the image reading area set by the main command dial 7 is read. The image readout area is a central area of the captured image set for each click of the main command dial 7 when the image readout area setting mode is selected from the menu screen displayed on the liquid crystal monitor 9 by the multi selector 8 (see FIG. 3 (b) and (c)). As shown in FIGS. 3B and 3C, frames 23a and 23b indicating the image reading area are displayed on the finder display 22 so as to be superimposed on the subject image. An image reading area can be selected. Note that an arbitrary image reading area may be set by moving the cursor on the viewfinder image with the up / down / left / right direction keys of the multi-selector 8.

  Next, in step 22, the continuous shooting speed corresponding to the image reading area, that is, the number of continuous shooting frames per second is calculated. This continuous shooting speed is the maximum speed at which a captured image can be read out from the set readout area while maintaining the same image quality as in the case of the continuous shooting speed up to 3 frames / second. The calculated number of continuous shots is displayed on the finder display 22 and the monitor 9, and the process proceeds to step 5. In addition, since the process of step 5-step 11 is the same as the process shown in FIG. 5, description is abbreviate | omitted.

  As described above, according to the second embodiment, the maximum continuous shooting speed that can be read from the set image reading area in the image captured by the image sensor 11 is calculated, and the image reading of the image sensor 11 is performed during continuous shooting. Since the captured image is read from the area at the maximum continuous shooting speed of the calculation result, the maximum continuous shooting speed can be automatically set according to the set image reading area, maintaining high image quality and wide The area image can be taken continuously at high speed.

  In addition, according to the second embodiment, the highest continuous shooting speed of the calculation result for reading the captured image from the set image reading area is displayed on the finder, so that it corresponds to the setting image reading area on the finder. The maximum continuous shooting speed can be confirmed.

  Furthermore, according to the second embodiment, since the frame indicating the set image readout area is displayed superimposed on the viewfinder image before starting continuous shooting, the set image readout is performed on the viewfinder. The area can be confirmed.

  Furthermore, according to the second embodiment, since only the captured image in the set image readout area is displayed on the finder before starting continuous shooting, readout at the time of continuous shooting on the finder. The image can be confirmed.

<< Modification of Embodiment >>
In the menu screen, either the continuous shooting speed priority shooting mode or the image readout area priority shooting mode can be selected, and when the continuous shooting speed priority shooting mode is selected, the set continuous shooting speed is used. When an image reading area wider than the maximum readable area is set, the area is limited to the maximum readable area. On the other hand, when the image reading area priority shooting mode is selected, the set image reading is performed. When a continuous shooting speed faster than the maximum continuous shooting speed that can be read from the area is set, the maximum continuous shooting speed that can be read is limited. Accordingly, it is possible to arbitrarily select whether to give priority to the continuous shooting speed or to give priority to the image reading area.

  In some cases, it may be desirable to read out the image in the image reading area set at the set continuous shooting speed even if the resolution of the captured image is lowered. Therefore, a speed / area setting shooting mode that enables simultaneous shooting speed setting and image readout area setting at the same time can be selected on the menu screen, and this setting is made when this speed / area setting shooting mode is selected. If the image in the image reading area set at the continuous shooting speed cannot be read, the mode automatically shifts to a known pixel addition reading mode, and the adjacent pixels are treated as one pixel, and their pixel values Are read out as one pixel value. In this way, in addition to the continuous shooting speed priority setting and the image reading area priority setting described above, the continuous shooting speed and the image reading area priority setting can be performed, and the function of continuous shooting can be expanded.

  The correspondence between the constituent elements of the claims and the constituent elements of the embodiment is as follows. In the embodiment, the main command dial 7 constitutes the speed setting operation member and the area setting operation member. However, the main command dial 7 may be constituted by the sub command dial 6 or the multi selector 8, for example. Further, the controller 20 constitutes an area computing means, a speed computing means, and an area / speed computing means, and the input circuit 12 and the controller 20 constitute an image reading means. Further, the display drive circuit 21 and the finder display 22 constitute area display means and speed display means, and the display drive circuit 21 constitutes finder display control means. In addition, as long as the characteristic function of this invention is not impaired, each component is not limited to the said structure.

DESCRIPTION OF SYMBOLS 1 Camera body 2 Shooting lens barrel 3 Shutter button 3a Shutter button switch 4 Liquid crystal display 5 Mode dial 5a Mode dial switch 6 Subcommand dial 6a Subcommand dial switch 7 Main command dial 7a Main command dial switch 8 Multi selector 8a Multi selector Switch 9 LCD monitor 10 Menu button 10a Menu button switch 11 Image sensor 12 Input circuit 13 Compression / expansion circuit 14 Distance measuring device 15 Lens drive device 16 Buffer memory 17 Monitor image generation circuit 18 Display drive circuit 19 Memory card 20 Controller 20a CPU
20b Memory 21 Display drive circuit 22 Viewfinder display 23 Image reading area frame

Claims (8)

An image sensor that captures a subject image and can read an image in an arbitrary area of the captured image;
A speed setting operation member for setting a continuous shooting speed;
Detecting means for detecting a position of a main subject in an image read from the image sensor by subject recognition processing;
Area calculating means for automatically setting a maximum image reading area capable of reading a captured image from the image sensor at a continuous shooting speed set by the speed setting operation member;
Image reading means for reading a captured image of the image reading area set by the area calculation means at a continuous shooting speed set by the speed setting operation member from the image sensor during continuous shooting ;
The area calculating means sets the image reading area at the center of the captured image during the continuous shooting, and when the position of the main subject detected by the detecting means protrudes from the image reading area, the image reading area configure such that the main subject is not exposed to an electronic camera according to claim Rukoto. The electronic camera according to claim 1,
An electronic camera comprising: an area display unit that displays a frame indicating an image readout area set by the area calculation unit so as to be superimposed on a finder image before starting continuous shooting. The electronic camera according to claim 1 or 2,
An electronic camera comprising: a finder display control means for displaying only a captured image in an image reading area set by the area calculation means on a finder before starting continuous shooting. An image sensor that captures a subject image and can read an image in an arbitrary area of the captured image;
An area setting operation member for setting an area for reading an image from an image picked up by the image pickup element from a plurality of read image areas having different sizes ;
Speed calculation means for automatically setting the highest continuous shooting speed that can be read from the image reading area set by the area setting operation member in the image captured by the image sensor;
An electronic camera comprising: an image reading unit that reads a captured image at a continuous shooting speed set by the speed calculation unit from an image reading region set by the region setting operation member of the image sensor during continuous shooting. The electronic camera according to claim 4,
An electronic camera comprising speed display means for displaying a continuous shooting speed calculated by the speed calculation means on a finder. The electronic camera according to claim 4,
An electronic camera comprising: an area display unit that displays a frame indicating an image reading area set by the area setting operation member in a superimposed manner on a finder image before starting continuous shooting. The electronic camera according to claim 4,
An electronic camera comprising: a finder display control means for displaying only a captured image in an image reading area set by the area setting operation member on a finder before starting continuous shooting. An image sensor that captures a subject image and can read an image in an arbitrary area of the captured image;
A speed setting operation member for setting a continuous shooting speed;
Detecting means for detecting a position of a main subject in an image read from the image sensor;
Area calculating means for automatically setting a maximum image reading area capable of reading a captured image from the image sensor at a continuous shooting speed set by the speed setting operation member;
Image reading means for reading a captured image of the image reading area set by the area calculation means at a continuous shooting speed set by the speed setting operation member from the image sensor during continuous shooting;
The electronic camera characterized in that the area calculation means sets the image reading area based on the position of the main subject detected by the detection means.

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