JP5332381B2 - Electronic camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic camera capable of improving picture quality of a desired range within a screen by using a high-frame-rate photographing function. <P>SOLUTION: The electronic camera includes an imaging means of photographing a subject a plurality of times in a predetermined period and generating image signals representing images corresponding to a plurality of parts of imaging ranges of the respective photographing operations, a readout means of reading a plurality of image signals, representing images of specified parts of the plurality of parts out of the imaging means with respect to each of a plurality of photographing operations, and a composing means of putting together the plurality of image signals read out by the readout means to form images corresponding to the specified parts. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an electronic camera having a high frame rate photographing function.

  In recent years, the speed of image sensors has been increasing, and electronic cameras equipped with a high frame rate photographing function have also become common.

  The high frame rate shooting function can be used not only for moving image shooting but also for still image shooting. In application to a still image, for example, the appropriate exposure time is divided and exposed to 20 frames, and the obtained 20 frames of image data are synthesized while correcting the deviation of the subject, thereby averaging the noise in the shooting of each frame, There is a technique for generating a high-quality still image (see Patent Document 1).

  When the above-described high frame rate imaging is realized by an electronic camera equipped with an image sensor with a high pixel exceeding 10 million pixels, the image signal obtained by the image sensor is thinned and read out. Thus, the substantial number of pixels forming each frame is reduced (see Patent Document 2).

As described above, even when high frame rate shooting is realized using thinning readout, an image quality improvement effect due to noise averaging can be expected by combining images of a plurality of frames.
JP 2006-86978 A Japanese Patent Laying-Open No. 2005-210218

  By the way, when shooting for athletics etc., a camera that is in focus at the start point, goal point, throwing start point, etc. is installed in the track or field in advance, and a photographer who is in a remote place such as a spectator seat Remote shooting may be performed using a remote control device. Also, in the field of wildlife ecology observation, cameras are installed so that the entire nest and water field are captured within the shooting range, and periodic shooting and remote shooting are performed.

  In such an image acquired by remote shooting or an image acquired by a surveillance camera, a small part of a wide range captured on the screen may be used in an enlarged manner.

  As described above, in the conventional high frame rate imaging in which the image signal is thinned and read out for an application in which a part of the image is enlarged and used, it is expected from the original number of pixels included in the image sensor. Could not provide image quality.

  An object of the present invention is to provide an electronic camera that can improve image quality within a desired range in a screen by using a high frame rate photographing function.

  The above-described object can be achieved by the electronic camera disclosed below.

The electronic camera is characterized by imaging means for imaging a subject a plurality of times within a predetermined period, and generating image signals representing images corresponding to a plurality of divided readout areas included in the imaging range in each imaging, in the course of times of photographing, a plurality of image signals representing an image of the designated plurality of divided reading regions from among a plurality of divided read area, in a predetermined order, and reading means for reading in time division from the imaging means, the reading And a synthesizing unit that synthesizes the plurality of image signals read by the unit for each of the designated divided reading areas .

  In the electronic camera having the basic configuration described above, the image quality within a desired range in the screen can be improved by using the high frame rate photographing function.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
FIG. 1 shows an electronic camera according to an embodiment of the present invention.

  An image signal representing a subject image formed on the photoelectric conversion surface of the image sensor 12 by the photographing optical system 11 of the electronic camera shown in FIG. 1 is subjected to gain adjustment corresponding to the photographing sensitivity by the signal processing unit 13. And then converted to digital data. Image data composed of digital data corresponding to each pixel of the image sensor 12 is sent to the image processing unit 20 via the memory 14, subjected to necessary image processing, and then via the recording interface (I / F) 17. Is recorded in a storage medium such as the memory card 18.

  The imaging control unit 15 illustrated in FIG. 1 passes necessary setting information to the image sensor 12, the signal processing unit 13, and the image processing unit 20 according to an instruction input in advance by a user via an operation panel (not shown). At the same time, the operation of each unit is controlled in accordance with a release instruction input via the receiver 16. That is, the electronic camera shown in FIG. 1 operates as a remote camera.

  The image processing unit 20 illustrated in FIG. 1 includes an image composition unit 21 and a composite image holding unit 22 and a composition control unit 23 that controls operations of these units for image composition processing.

  The shooting control unit 15 uses a high frame rate shooting function (for example, a function capable of acquiring an image of several hundred to 1,000 frames per second) for still image shooting by a setting operation before shooting by the user. An instruction and designation of a range to be noted (hereinafter referred to as a range of interest) in the imaging range captured by the imaging device 12 can be received. As this attention range, for example, as shown by a thick broken line in FIGS. 2A and 2B, the image signal from the image sensor 12 during the frame readout time d corresponding to the frame rate realizable by the image sensor 12. Can be set by freely arranging the divided readout areas in which the image can be read out in the imaging range. In FIG. 2, when the image signal corresponding to a pixel corresponding to a quarter of all the pixels of the image sensor 12 can be read in the frame readout time d, the light receiving surface of the image sensor 12 is divided into four equal parts. An example in which two divided read areas corresponding to a rectangle are arranged side by side (see FIG. 2A) and an example in which two divided read areas are arranged obliquely (see FIG. 2B) are shown. The divided readout area can be freely set in both shape and size as long as the image signal can be read from the image sensor 12 within the above-described divided exposure time d.

  Hereinafter, a method for acquiring a high-quality image for the range of interest using the high frame rate imaging function will be described.

  FIGS. 3A and 3B are flowcharts showing photographing operations suitable for a remote camera.

  First, the imaging control unit 15 sets an attention range based on an instruction input in the setting operation before imaging (step S1 in FIG. 3A), and then sets the attention range as the frame readout time d described above. The data is divided into readable divided read areas, and the read order for these divided read areas is determined (step S2). For example, when the attention range as shown in FIG. 2A is set, the imaging control unit 15 determines a reading order in which the two divided reading areas 1 and 2 are alternately specified, and follows this reading order. The operation of the signal processing unit 13 may be controlled so that the image signals of all the pixels belonging to the designated divided readout area are read out without being thinned out.

  After the preparation for shooting is completed in this way, step S3 is repeated to wait for a shooting instruction, and when the release button is notified via the receiver 16 (positive determination in step S3), high frame rate shooting is performed. Start shooting using the function.

  In high frame rate imaging, as shown in FIG. 4, divided exposure imaging is performed N times (for example, 20 times) obtained by dividing the appropriate exposure time S by the frame readout interval d when the high frame rate imaging function is applied. And N frames of images are obtained. In FIG. 4, the exposure sections corresponding to each divided exposure shooting are indicated by reference numerals “exposure” with numbers indicating the order, and the images acquired in each divided exposure shooting are also given the same numbers. Indicated.

  Each time each divided exposure shooting is performed (step S4), the shooting control unit 15 instructs the signal processing unit 13 to read the image signal corresponding to the divided reading area specified in the reading order described above (step S4). In response to this, the signal processor 13 reads out the image signals of all the pixels belonging to the designated divided readout area without being thinned out (step S6), and converts them into corresponding image data.

  For example, in the example shown in FIG. 2A, as shown in FIG. 4, the image signal of the divided readout area 1 is displayed in the odd-numbered exposure section, and the image signal of the divided readout area 2 is displayed in the even-numbered exposure section. The image data is read out by the signal processing unit 13 and corresponding image data is generated.

  The image data generated in this way is transferred to the image composition unit 21 of the image processing unit 20 via the memory 14 and is subjected to image composition processing (step S7).

  The image composition unit 21 receives information for designating a divided readout area corresponding to the image data to be composed via the composition control unit 23 (step S7-1 in FIG. 3B), and image data from the memory 14. (Step S7-2), and is synthesized for each divided readout region (step S7-3). Then, the synthesized image holding unit 22 holds the synthesized image data. At this time, the image composition unit 21 performs image composition processing, for example, by adding the image data corresponding to each divided readout area already held in the composite image holding unit 22 and the newly received image data. This can be executed for each divided readout area.

  By repeating Steps S4 to S8 in the flowchart shown in FIG. 3A, for example, as shown in FIG. Thus, the divided readout areas are sequentially synthesized.

  Thereafter, when the divided exposure shooting corresponding to all the divided exposure sections is completed (affirmative determination in step S8), for example, when the divided exposure shooting is performed with the appropriate exposure time of 20 frames, the divided read areas 1 and 2 are read. A composite image obtained by combining 10 frames of the divided exposure photographed image is obtained, and the process is terminated.

  When divided exposure shooting is performed with the electronic camera described above, an image acquired corresponding to each divided exposure section includes information corresponding to image signals of all the pixels of the image sensor 12 included in the divided readout area. Yes. Therefore, information corresponding to the image signals of all the pixels of the image sensor 12 included in the attention range is obtained by synthesizing the image acquired corresponding to each divided exposure section for each divided readout region as described above. Can be obtained.

  In such a composite image, the high resolution expected from the number of pixels provided in the image sensor 12 is maintained, and noise is averaged by combining the images obtained by the divided exposure photography. It is also possible to obtain an image quality improvement effect due to.

  For example, in remote shooting of track and field events, the imaging range is set so that the players lined up on the start line fall within the attention range shown in FIG. 2 (a). When shooting using frame rate shooting, it is possible to obtain an image with a higher resolution than when shooting simply at a high frame rate for the same imaging range within the above-mentioned range of interest. It is.

  In this way, in the composite image obtained by setting the range of interest and shooting using the high frame rate shooting function, noise is averaged and high resolution is realized. Even when a part of the attention range (for example, one of the players lined up on the start line) is cut out and enlarged, it is possible to obtain a high-quality image that can be expected from the number of pixels of the image sensor 12 mounted on the electronic camera. it can.

  Therefore, the electronic camera having the configuration as shown in FIG. 1 is very useful in applications such as remote shooting such as athletics and wildlife ecology observation.

  In particular, it is useful for applications such as wildlife ecology, such as when observing wild birds nesting, focusing on both the entrance to the nest box and the nest formed at the bottom of the nest box. is there. In this case, as shown in FIG. 2 (b), using the fact that the range of interest can be set freely, the entire nest box is kept within the imaging range, and the vicinity of the nest box entrance and the bottom of the nest box A range of interest including the divided readout area corresponding to can be set.

On the other hand, it is also possible to dynamically determine a range of interest using a moving object detection technique for a surveillance camera such as a security camera.
(Embodiment 2)
FIG. 5 shows an electronic camera according to another embodiment of the present invention.

  Note that among the components shown in FIG. 5, components equivalent to those shown in FIG. 1 are denoted by the same reference numerals, and description thereof is omitted.

  The electronic camera shown in FIG. 5 is configured to operate as a surveillance camera, and the transmission / reception unit 27 periodically or irregularly transmits a shooting instruction from a surveillance camera control unit (not shown) located at a remote location. Receive. In response to the photographing instruction, the photographing control unit 15 controls the image signal reading operation by the signal processing unit 13.

  Further, in response to this shooting instruction, the shooting control unit 15 inputs the image data generated by the signal processing unit 13 and transmits the image data to the monitoring camera control unit via the transmission / reception unit 27. With such a configuration, the captured images are sequentially sent to the monitoring camera control unit, so that the monitoring camera control unit can monitor these images to display them as a through image.

  Further, the composite image data generated by the image composition unit 21 and retained in the composite image retaining unit 22 can be output to the photographing control unit 15 via the composition control unit 26. Then, the imaging control unit 15 can transmit the composite image data to the monitoring camera control unit via the transmission / reception unit 27.

  In addition, what is necessary is just to comprise so that communication with the transmission / reception part 27 and the surveillance camera control part can be performed by wireless LAN etc. FIG.

  In addition, the image processing unit 210 illustrated in FIG. 5 includes a moving object detection unit 24, a reference image holding unit 25, and a synthesis control unit 26, instead of the synthesis control unit 23 illustrated in FIG. For example, the moving object detection unit 24 receives an image corresponding to the first exposure section obtained by the divided exposure shooting by the high frame rate shooting function from the memory 14 and holds the image in the reference image holding unit 25. The moving object within the imaging range is detected by comparing the image corresponding to the last exposure section, and the detection result is provided to the process of the synthesis control unit 26.

  As shown in FIG. 6A, the imaging control unit 15 is set in advance with the entire imaging range as an initial state of the attention range, and a detection result indicating that a moving object has been detected via the synthesis control unit 26. Is received, the imaging control unit 15 performs control to narrow the attention range based on the detection result.

  Hereinafter, a method for acquiring a composite image suitable as a surveillance camera by switching the attention range according to the moving object detection result will be described.

  FIG. 7 is a flowchart showing a photographing operation suitable for the surveillance camera.

  At the start of shooting, the shooting control unit 15 sets the entire imaging range as the attention range in accordance with the above-described initial setting (step S11). Next, for example, the imaging control unit 15 regards this attention range as a set of four divided read areas, and determines the read order so that these divided read areas 1 to 4 are read cyclically according to the numerical order (step). S12, see FIG. 6 (a)).

  Thereafter, step S13 is repeated to wait for a shooting instruction from a monitoring camera control unit (not shown), and in response to the reception of the shooting instruction (affirmative determination in step S13), similarly to steps S4 to S8 in FIG. An image captured by the divided exposure is synthesized for each divided readout area to generate a synthesized image (step S14).

  In this process, for example, the moving body detection unit 24 uses, for example, an image acquired first for each divided readout area (an image obtained corresponding to the first to fourth divided exposures) as a reference image corresponding to each divided readout area. Are stored in the reference image holding unit 25, and these divided read areas are compared with the last acquired image to detect a moving object appearing in each divided read area (step S15).

  By comparing the reference image with the last acquired image, for example, as shown in FIG. 6 (a), it is possible to detect a moving object appearing in the divided readout area 1 and specify the moving direction thereof. it can.

  When the moving object is detected in this manner (Yes determination in step S16), the imaging control unit 15 selects the detected moving object based on the detection result received from the moving object detection unit 24 via the synthesis control unit 26. An attention range is set so as to be tracked (step S17). For example, in the i-th shooting, when a moving body that moves in the direction indicated by the arrow is detected in the divided readout area 1 as shown in FIG. 6A, the shooting control unit 15 performs the (i + 1) -th shooting. As shown in FIG. 6B, for each of the shooting, the (i + 2) th shooting, and the (i + 3) th shooting, an attention range in which the upper left coordinate of the divided readout area 1 is shifted in the moving direction can be set.

  Thereafter, it is confirmed that monitoring continuation is instructed from a monitoring camera control unit (not shown) (affirmative determination in step S18), and the imaging control unit 15 returns to step S12 and sets the newly set attention. The divided readout area and readout order are determined so as to fit the range.

  As described above, when the range of interest is narrowed down to a range having the same size as that of one divided readout area, each of the images acquired by the divided exposure shooting at the high frame rate shooting by the shooting control unit 15. Thus, the reading operation by the signal processing unit 13 is controlled so as to read the narrowed attention range.

  Therefore, when high frame rate shooting is performed in accordance with the next shooting instruction, as shown in FIG. 6B, images of the attention range set to track moving objects are not thinned out. By synthesizing all the acquired images acquired for the divided exposure section, it is possible to acquire a combined image with extremely high resolution and high image quality for this attention range.

  In this way, the ability to acquire a high-resolution and high-quality composite image for the range in which a moving object appears is a very useful feature for surveillance cameras installed for crime prevention purposes.

  When the moving object has escaped from the focused range narrowed down as described above, or when no moving object is detected within the imaging range (negative determination in step S16), the imaging control unit 15 performs the entire imaging range. Is set as the attention range, and the attention range is returned to the initial setting (step S19).

  In the electronic camera according to the above-described embodiment, the signal processing unit 13 selectively reads out a designated part of the imaging range in each shooting performed by the imaging device 12 within a predetermined time, and the image processing unit 20 or 210 for each part. To synthesize. In that case, in this case, the image signal read from the image sensor 12 by the signal processing unit 13 corresponding to each photographing is limited to the image signal indicating the image corresponding to the designated portion. Correspondingly, it is possible to read out the image signals corresponding to all the pixels without thinning them out and use them for the composition processing.

  Therefore, according to the electronic camera of the above-described embodiment, in a shooting where the imaging range is fixed, such as a remote shooting for sports competitions, a surveillance camera, and a wildlife ecology observation camera, high image quality is obtained for a desired region of the imaging range. Images can be provided.

It is a figure which shows the electronic camera of one Embodiment of this invention. It is a figure explaining an attention range and a division | segmentation read-out area | region. It is a flowchart showing the imaging | photography operation | movement suitable for a remote camera. It is a figure explaining a synthetic | combination process. It is a figure which shows the electronic camera of another embodiment of this invention. It is a figure explaining the attention range determination process based on a moving body detection. It is a flowchart showing the imaging | photography operation | movement suitable for the surveillance camera.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Shooting optical system, 12 ... Image sensor, 13 ... Signal processing part, 14 ... Memory, 15 ... Shooting control part, 16 ... Receiver, 17 ... Recording interface (I / F), 18 ... Memory card, 20 ... Image Processing unit, 21... Image composition unit, 22... Composite image holding unit, 23 and 26... Composition control unit, 24.

Claims (4)

Imaging means for imaging a subject a plurality of times within a predetermined period and generating an image signal representing an image corresponding to each of a plurality of divided readout regions included in an imaging range in each imaging;
Reading out a plurality of image signals representing images in a plurality of divided reading areas designated from among the plurality of divided reading areas in a time-division manner from the imaging unit in the process of the plurality of times of photographing. Means,
An electronic camera comprising: combining means for combining the plurality of image signals read by the reading means for each of the designated divided reading areas. Imaging means for capturing an image of a subject multiple times within a predetermined period and generating an image signal representing an image within an imaging range in each imaging;
A reading unit that reads out image signals representing images corresponding to each of the plurality of divided reading areas included in the imaging range in a time-division manner from the imaging unit in the course of the plurality of times of shooting;
An electronic camera comprising: a combining unit that combines the plurality of image signals read by the reading unit for each of the divided reading regions. The electronic camera according to claim 2,
When a moving object is detected within the imaging range in the plurality of imaging steps, a part including the moving object is specified, and an image signal of the part including the moving object from the imaging unit to the reading unit Has a range specifying means for reading
The electronic camera characterized in that, when the moving object is detected, the combining means combines the image signals read by the reading means to form an image corresponding to the moving object. The electronic camera according to claim 1 or 2,
The electronic camera according to claim 1, wherein the divided readout area is set according to an amount of an image signal that can be read from the imaging unit at a time obtained by dividing the predetermined period by the number of times of photographing performed in the predetermined period.

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