JP2006238205A - Imaging apparatus and imaging method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a high-definition still images, without breaking a moving image, when photographing the still image at an arbitrary time point during photographing of moving image. <P>SOLUTION: This imaging apparatus is provided, including an imaging device for generating an image signal by photoelectric conversion for each pixel, a first read means for sequentially reading image signals from a plurality of pixels of the imaging device separately for (m) fields ((m) is a natural number of ≥2), a second read means for continuously reading image signals of specific one field among the (m) fields, a first image generating means for generating moving image signals for the (m) fields and generating a still image signal of a single frame, based on the read image signals of the (m) fields, and a second image generating means for generating a moving image signal, based on the continuously read image signals of the specific single field. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an imaging apparatus and an imaging method.

  In recent years, many digital cameras for obtaining still images or moving images using an image sensor such as a CCD have been developed. The moving images of these cameras were originally used for framing, but now they are an incidental function that requires the recording of moving images, and in the future, standard television (approximately VGA size (640 × 480), 30 seconds) It is expected that higher definition and higher frame rate will be achieved.

  The demand for the market that comes with higher definition of moving images is a still image cut-out function at an arbitrary time point of moving images. Although the current video recording function has various compression methods, it basically only arranges images of about VGA, so even if you extract a point and treat it as a still image, you can get enough resolution to print etc. I can't.

  In view of this, there has been proposed an imaging apparatus having a function of capturing a high-resolution still image during display / recording of a moving image. (For example, see Patent Documents 1 and 2)

JP-A-5-244553 JP 2004-80354 A

  However, in the above-mentioned Patent Document 1, a system is provided in which both a moving image capturing device that captures a moving image and a still image capturing device that captures a still image are installed, resulting in an expensive and large-sized system. . In Japanese Patent Laid-Open No. 2004-228561, the image capturing apparatus can be shared for moving images and still images, but if a still image is recorded in the middle of recording a moving image, the moving image is interrupted.

  The present invention has been made in view of the above problems, and its purpose is to capture a high-definition still image without interrupting the displayed / recorded moving image when shooting a still image at any time during moving image shooting. It is an object to provide an imaging apparatus and an imaging method capable of obtaining the above.

  An imaging apparatus according to the present invention sequentially reads out image signals by dividing an image sensor for generating an image signal by photoelectric conversion for each pixel into m fields (m is a natural number of 2 or more) from a plurality of pixels of the image sensor. A first readout means; a second readout means for successively reading out an image signal of one specific field of the m fields; and a moving image signal of an m field based on the read out image signal of the m field. A first image generation unit that generates a still image signal of one frame and a second image generation unit that generates a moving image signal based on the image signal of the specific one field read out continuously. It is characterized by having.

  An imaging method of the present invention is an imaging method of an imaging apparatus having an imaging device for generating an image signal by photoelectric conversion for each pixel, and includes m fields (m is a natural number of 2 or more) from a plurality of pixels of the imaging device. ), Sequentially reading out the image signal, a second reading step of successively reading out the image signal of one specific field of the m fields, and the read out image signal of the m field. Based on the first image generation step for generating an m-field moving image signal and a still image signal for one frame based on the image signal for the specific one field read out continuously, the moving image signal is generated. And a second image generation step.

  When shooting a still image at an arbitrary time during moving image shooting, a high-definition still image can be obtained without interrupting the moving image.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing a schematic configuration of a digital camera according to the first embodiment of the present invention. The optical system 11 including a lens forms a subject image on the light receiving surface of the CCD 12. The CCD 12 is an image sensor that photoelectrically converts an optical signal of a subject imaged on its light receiving surface to generate an electric signal (charge) for each pixel. A mechanical shutter (mechanical shutter) 13 is disposed between the optical system 11 and the CCD 12, and the light incident on the CCD 12 can be blocked by closing the mechanical shutter 13.

  The output of the CCD 12 driven by the CCD driving device 14 that generates a timing pulse for CCD driving is digitized by a pre-process circuit 15 including a sample hold (S / H), a gain amplifier, and an analog / digital conversion (A / D) circuit. And taken into the digital process circuit 16. The digital process circuit 16 performs various digital signal processing such as gamma processing and color signal processing. At this time, the image signal is written to / read from the memory 17. The output of the digital process circuit 16 can be output to a display (display means: LCD) 18.

  The image data that has been subjected to image processing by the digital process circuit 16 is compressed via the image conversion circuit 19, written to the memory card 20, and recorded. The image conversion circuit (recording unit) 19 compresses the image data from the digital process circuit 16 and records (outputs) the image data on the memory card 20, and decompresses the image data read from the memory card 20 to expand the digital process circuit 16. This is a device having a function to output to

  Each of the optical system 11, the mechanical shutter 13, the CCD driving device 14, the preprocess circuit 15, the digital process circuit 16, the image conversion circuit 19, and the memory card 20 is controlled by the camera control unit 21. An operation unit 22 having functions such as release, output image size switching, and reading mode switching is connected to the camera control unit 21.

  Next, the configuration of the interline CCD 12 used in the digital camera of this embodiment will be described. FIG. 2 shows the configuration of the CCD 12. The CCD 12 is an interline type solid-state imaging device, and a plurality of photoelectric conversion elements (pixels) 1 that are arranged in a matrix and convert incident light into charges for each pixel, and signals stored in each of the pixels 1. A vertical transfer unit (VCCD) 2 for reading out charges and transferring them in the vertical direction; a horizontal transfer unit (HCCD) 3 for transferring signal charges for one line transferred from the vertical transfer unit 2 in the horizontal direction; An output amplifier unit 4 is provided for converting the signal charge transferred from the horizontal transfer unit 3 into an electric signal. The photoelectric conversion element 1 is, for example, a photodiode. The solid-state imaging device (CCD) 12 generates an image signal by photoelectric conversion for each pixel.

  FIG. 3 shows a pixel arrangement. In this embodiment, it is assumed that the number of pixels of 2,400 (H) columns × 1,800 (V) rows is three-field readout. The color filter array will be described as a so-called Bayer array in which there are an RG line in which R and G are alternately arranged in the horizontal direction and a GB line in which G and B are alternately arranged in the horizontal direction.

  Also, the shaded pixels in FIGS. 4A, 4B, and 4C are read out in the A, B, and C fields, respectively (fields 2, 400 (H) columns × 600 (V) rows), A, B, and C are field names of three fields.

  As a first shooting mode in the digital camera of this embodiment, a still image shooting mode will be described with reference to the timing chart of FIG. VD is a vertical synchronization signal, a release signal is a signal generated when the user presses a release button disposed on the operation unit 22, a mechanical shutter 13 controls exposure by opening and closing, and an electronic shutter is generated by the CCD driving device 14. Exposure is controlled by applying a pulse to the substrate potential of the CCD 12 and extracting the charge of the pixel 1 toward the substrate. The high-speed sweep-out (sweep-out) operation is an operation in which the vertical transfer unit (VCCD) 2 is operated at a high speed, and signals such as smear accumulated in the vertical transfer unit 2 are swept out of the transfer path. The readout pulse is a pulse generated by the CCD driving device 14 and applied to read out the signal accumulated in the pixel 1 in the corresponding field to the vertical transfer unit 2.

  When taking a still image with the digital camera of this embodiment, after the release, the mechanical shutter 13 is closed after a predetermined exposure time, and an amount of electric charge corresponding to the amount of light of the subject is accumulated in each pixel 1. Thereafter, the charge of the pixel is divided into three fields, read to the vertical transfer unit 2, and transferred via the vertical transfer unit 2 and the horizontal transfer unit 3. Further, a high-speed sweep-out period is provided before reading out the pixels of each field, and the smear component remaining in the vertical transfer unit 2 is removed. This high-speed sweep-out period is also a feature of still image shooting according to the present embodiment for moving-image shooting that is continuously read out without performing high-speed sweep-out. FIG. 5 illustrates the above. After the release signal, an electronic shutter pulse is applied to extract the charge of the pixel 1, the mechanical shutter 13 is closed after a predetermined exposure time, and then read out in the cycle of the vertical synchronization signal VD. Along with pulse application, pixels in the A, B, and C fields are sequentially read from the CCD. The high-speed sweep-out period is provided before each reading. Pixels in each field (each 2,400 × 600) are read out and stored in the memory 17 through the preprocess circuit 15 and the digital process circuit 16, and the images in the three fields on the memory 17 undergo image processing. It is generated as a still image (2,400 × 1,800). This is recorded on the memory card 20 and displayed on the LCD 18.

  Next, a moving image shooting mode as a second shooting mode in the digital camera of the present embodiment will be described with reference to the timing chart of FIG.

  Considering the frame rate, file size, etc., the moving image in the digital camera of this embodiment is considered to be a vertical number that is about 1/3 of the still image, and only the pixels in the A field are read out of all the pixels. , And moving images. At this time, since pixels in the horizontal direction are also thinned at the same thinning rate as vertical, the final number of pixels of the moving image is 800 × 600 with respect to the still image 2,400 × 1,800.

  Moving image shooting in the present embodiment is as shown in FIG. 6, and pixels in the A field are read out from the CCD along with the application of the readout pulse in the period of the vertical synchronization signal VD. A moving image generated through image processing in the memory 17 is recorded on the memory card 20 or displayed on the LCD 18.

  The exposure time of each field image is adjusted by adjusting the number of applied electronic shutter pulses. The mechanical shutter closing and high-speed sweeping operations are not performed.

  The A field signal read in each vertical synchronization signal VD period has a size of 2,400 × 600, but the pixels in the horizontal direction are thinned out to 1/3 during image processing, and 800 × 600. The size is changed. Then, as shown in FIG. 6, it is recorded on the memory card 20 as a moving image or displayed on the LCD 18. In FIG. 7A, shaded pixels represent pixels used as moving images among pixels read out from the CCD (A field pixels), and hatched pixels represent pixels that are thinned out in the horizontal direction. . FIG. 7B shows a pixel 800 × 600 after thinning.

  Subsequently, a moving image still image shooting mode will be described as a third shooting mode in the digital camera of the present embodiment.

  First, the moving image still image shooting mode according to the first embodiment of the present invention will be described with reference to FIG.

  In the moving image still image shooting mode, a release signal is generated when the user presses a release button disposed on the operation unit 22, and still image shooting is started in response to the signal. Since the moving image shooting before the release signal is generated is the same as the moving image shooting mode which is the second shooting mode, description thereof is omitted.

  A description will be given after the release signal is generated. When a release signal is generated, a read pulse is applied to each of the A, B, and C fields from the next vertical synchronizing signal VD to sequentially read out the respective field images. At this time, the exposure time of each field image is adjusted by adjusting the number of applied electronic shutter pulses. The mechanical shutter closing and high-speed sweeping operations are not performed.

  The field signals read out in each vertical synchronization signal VD period have a size of 2,400 × 600, and after these are read out, they are stored in the memory 17 via the preprocess circuit 15 and the digital process circuit 16. The

  In order to continue outputting the moving image during each vertical synchronization signal VD period, the following processing is performed. When the image of the A field is read, the horizontal pixels are thinned out to 1/3 with respect to the 2,400 × 600 image signal on the memory 17 and the size is changed to 800 × 600. Then, as shown in FIG. 8, it is recorded on the memory card 20 as a moving image or displayed on the LCD 18. In FIG. 9A, the center of gravity of the A field is represented by *.

  When the image of the B field is read out, the pixels in the horizontal direction are thinned out to 1/3 with respect to the 2,400 × 600 image signal on the memory 17 and the size is changed to 800 × 600. Further, since the center of gravity is different from other moving image signals (A field), the center of gravity is corrected. In FIG. 9B, the center of gravity of the B field is represented by *. The center of gravity is corrected to the position of ☆ so as to match the center of gravity of the A field. Then, the image subjected to gravity center correction (indicated by * in the figure) is recorded on the memory card 20 as a moving image or displayed on the LCD 18 as shown in FIG.

  When the image of the C field is read, the horizontal pixels are thinned out to 1/3 with respect to the 2,400 × 600 image signal on the memory 17 and the size is changed to 800 × 600. Further, since the center of gravity is different from other moving image signals (A field), the center of gravity is corrected. In FIG. 9C, the center of gravity of the C field is represented by *. The center of gravity is corrected to the position of ☆ so as to match the center of gravity of the A field. Then, the image subjected to gravity center correction (indicated by * in the figure) is recorded on the memory card 20 as a moving image or displayed on the LCD 18 as shown in FIG.

  As described above, in the moving image still image mode, each field image subjected to the gravity center correction is used for recording / displaying, so that the moving image is not interrupted even after the release.

  Subsequently, generation of a still image will be described. Each field image of A, B, and C recorded on the memory 17 is generated as a still image (2,400 × 1,800) through image processing by the digital process circuit 16. This is recorded in the memory card 20 after the end of moving image recording / display.

  As described above, according to the present embodiment, a high-definition still image can be taken at any time during moving image shooting without interrupting the moving image being displayed / recorded.

(Second Embodiment)
A moving image still image shooting mode according to the second embodiment of the present invention will be described with reference to FIG.

  In the moving image still image shooting mode, a release signal is generated when the user presses a release button disposed on the operation unit 22, and still image shooting is started in response to the signal. Since the moving image shooting before the release signal is generated is the same as the moving image shooting mode which is the second shooting mode, description thereof is omitted.

  A description will be given after the release signal is generated. When the release signal is generated, the mechanical shutter 13 is closed after a predetermined exposure time. Then, a read pulse is applied to each of the A, B, and C fields from the next vertical synchronizing signal VD, and the respective field images are sequentially read out. At this time, the exposure time until the mechanical shutter is closed is adjusted by adjusting the number of applied electronic shutter pulses. In addition, a high-speed sweep period is provided before each reading to remove smear components remaining in the vertical transfer unit.

  The field signals read out in each vertical synchronization signal VD period have a size of 2,400 × 600, and after these are read out, they are stored in the memory 17 via the preprocess circuit 15 and the digital process circuit 16. The

  In order to continue outputting the moving image during each vertical synchronization signal VD period, the following processing is performed. When the image of the A field is read, the horizontal pixels are thinned out to 1/3 with respect to the 2,400 × 600 image signal on the memory 17 and the size is changed to 800 × 600. Then, as shown in FIG. 10, it is recorded on the memory card 20 as a moving image or displayed on the LCD 18.

  When the image of the B field is read out, the pixels in the horizontal direction are thinned out to 1/3 with respect to the 2,400 × 600 image signal on the memory 17 and the size is changed to 800 × 600. Further, since the center of gravity is different from other moving image signals (A field), the center of gravity is corrected. In FIG. 9B, the center of gravity of the B field is represented by *. The center of gravity is corrected to the position of ☆ so as to match the center of gravity of the A field. Then, the image subjected to the gravity center correction (indicated by * in the figure) is recorded on the memory card 20 as a moving image or displayed on the LCD 18 as shown in FIG.

  When the image of the C field is read, the horizontal pixels are thinned out to 1/3 with respect to the 2,400 × 600 image signal on the memory 17 and the size is changed to 800 × 600. Further, since the center of gravity is different from other moving image signals (A field), the center of gravity is corrected. In FIG. 9C, the center of gravity of the C field is represented by *. The center of gravity is corrected to the position of ☆ so as to match the center of gravity of the A field. Then, the image subjected to the gravity center correction (indicated by * in the figure) is recorded on the memory card 20 as a moving image or displayed on the LCD 18 as shown in FIG.

  As described above, in the moving image still image shooting mode, each field image subjected to gravity center correction is used for recording / displaying, so that the moving image is not interrupted even after the release.

  Subsequently, generation of a still image will be described. Each field image of A, B, and C recorded on the memory 17 is generated as a still image (2,400 × 1,800) through image processing by the digital process circuit 16. This is recorded in the memory card 20 after the end of moving image recording / display.

  As described above, according to the present embodiment, a high-definition still image can be taken at any time during moving image shooting without interrupting the moving image being displayed / recorded. Further, by closing the mechanical shutter when sequentially reading all fields, there is no exposure time shift between fields, and the false color of a moving subject in a still image can be suppressed.

  As described above, according to the first and second embodiments, when still image shooting is instructed by the release button, the moving image still image shooting mode is set. In the moving image still image shooting mode, the example in which all the pixels of the CCD 12 are divided into three fields by interlace scanning and the image signal is sequentially read has been described. However, the present invention is not limited to three fields, and m fields (m is a natural number of 2 or more). Can be read separately. Then, based on the read m-field image signal, an m-field moving image signal is generated and a still image signal of one frame is generated. As a result, a high-definition still image can be taken at any time during moving image shooting without interrupting the moving image being displayed / recorded.

  In addition, when a still image shooting is not instructed by the release button, the moving image shooting mode is set. In the moving image shooting mode, an image signal of a specific one field (for example, A field) of m fields is continuously read in synchronization with the vertical synchronization signal VD, and the image signal of the specific one field read continuously is read. Based on this, a moving image signal is generated.

  The above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

It is a block diagram which shows schematic structure of the digital camera of embodiment of this invention. It is a figure which shows the outline of the internal structure of CCD shown in FIG. It is a figure which shows the pixel arrangement | sequence in embodiment of this invention. It is a figure which shows the pixel arrangement | sequence of each field in embodiment of this invention. FIG. 4 is a timing diagram of a still image shooting mode in the embodiment of the present invention. FIG. 6 is a timing chart of a moving image shooting mode in the embodiment of the present invention. It is a figure which shows the read-out pixel of the video recording mode in embodiment of this invention. FIG. 3 is a timing chart of a moving image still image shooting mode according to the first embodiment of the present invention. It is a figure which shows the read-out pixel of the still image shooting mode in moving image in embodiment of this invention. It is a timing diagram of the still image shooting mode during moving images in the second embodiment of the present invention.

Explanation of symbols

1 Photoelectric conversion element (pixel)
2 Vertical transfer unit (VCCD)
3 Horizontal transfer unit (HCCD)
4 Output amplifier section 11 Optical system consisting of a lens 12 CCD
13 Mechanical shutter 14 CCD drive device 15 Preprocess circuit 16 Digital process circuit 17 Memory 18 Display (LCD)
19 Image conversion circuit 20 Memory card 21 Camera control unit 22 Operation unit

Claims (7)

An image sensor for generating an image signal by photoelectric conversion for each pixel;
First reading means for sequentially reading image signals from a plurality of pixels of the image sensor in m fields (m is a natural number of 2 or more);
Second reading means for continuously reading image signals of one specific field of the m fields;
First image generating means for generating an m-field moving image signal based on the read m-field image signal and generating a still image signal of one frame;
An image pickup apparatus comprising: a second image generation unit configured to generate a moving image signal based on the image signal of the specific one field read out continuously.   The imaging apparatus according to claim 1, wherein the first image generation unit generates an m-field moving image signal by correcting each center of gravity of the read m-field image signal.   The imaging apparatus according to claim 1, wherein the first image generation unit generates an m field moving image signal by thinning out the read m field image signal.   When still image shooting is instructed, an image signal is read by the first reading means and an image signal is generated by the first image generating means. When still image shooting is not instructed, the second reading means is read out. 4. The image pickup apparatus according to claim 1, wherein an image signal is read out and an image signal is generated by the second image generation unit. 5. Furthermore, it has a mechanical shutter for blocking light incident on the image sensor,
5. The imaging according to claim 1, wherein the first reading unit blocks light by closing the mechanical shutter when sequentially reading the image signals of the m field. apparatus. The imaging element includes a line in which the first color and the second color are alternately arranged in the order of the first color and the second color, and the third color and the first color are the third color. The colors and the lines alternately arranged in the order of the first color are arranged alternately,
The first readout means sequentially reads out image signals in three fields,
6. The imaging apparatus according to claim 1, wherein the second reading unit continuously reads an image signal of one specific field among the three fields. 7. An imaging method of an imaging apparatus having an imaging element for generating an image signal by photoelectric conversion for each pixel,
A first readout step of sequentially reading out an image signal from a plurality of pixels of the imaging device in m fields (m is a natural number of 2 or more);
A second readout step of successively reading out the image signal of one specific field of the m fields, generating a moving image signal of the m field based on the read out image signal of the m field, and stillness of one frame A first image generation step for generating an image signal;
And a second image generation step of generating a moving image signal based on the image signal of the specific one field read out continuously.

Images