JP2000138864A - Image pickup device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration in a video image caused on the occurrence of smears due to high luminance data in an image pickup device, such as a CCD, and to enhance the image quality. SOLUTION: A video camera 100 has a solid-state image pickup section, consisting of plural types of many photoelectric conversion elements sensing light that are arranged as a grating, and reads electric charges stored by the light in the photoelectric conversion elements as an electric signal for picking up the image of an object. Each photoelectric transfer element reads the signal plural times within a single-field period. The uppermost or the lowermost part of the solid-state image pickup section is provided with elements 13, 14 for detecting a vertical optical black reference, and the output from the detection elements 13, 14 is read per every reading that is conducted plural times within a single-field period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CCD, a video camera device, and the like for imaging a subject using a photoelectric conversion element.
The present invention relates to an imaging device such as a camera device.

[0002]

2. Description of the Related Art In today's video camera devices, a solid-state image pickup unit (CCD image sensor) formed by a plurality of photoelectric conversion elements is used as an image pickup means because it can be made smaller, lighter and lower cost than an image pickup tube. Is provided.
In general, a CCD image sensor has a solid-state imaging unit in which photoelectric conversion elements that receive light and accumulate the light as electric charges are arranged in a lattice shape, and read out the electric charges accumulated by each photoelectric conversion element, and read the electric charges. The data is transferred and output as a CCD output.

In such a conventional CCD image sensor, an OB element is provided to adjust an optical black reference. This OB element performs a so-called clamping process in which a photoelectric element provided at the outer edge of the solid-state imaging unit is shielded by aluminum or the like so that light does not shine, and an output from the OB element is used as an optical black reference to adjust an image. Is what you do.

FIG. 5A is a block diagram showing a conventional video camera apparatus in which a black reference is detected and an image is adjusted.

[0005] In the figure, the output from the black reference detecting element of the CCD 1 is sent to the CLP 52 of the CDS circuit 2. As shown in FIG. 5B, the signal transmitted here includes an effective image area including an image, a vertical black reference (VOB) located at the upper end thereof, and a horizontal black reference (VOB) located at the side. HOB).

Then, the CLP 52 performs a clamp process on the video signal based on the VOB signal or the HOB signal, and the BLK 53 blanks the VOB signal and the HOB signal, and sends them to the CDS 54 and the AGC 51. These devices are controlled by the TG 55.

In such a conventional CCD image sensor, electric charges accumulated in each photoelectric conversion element are read out once every one field period, and as shown in FIG. Is a form in which one field contains one image.

[0008] In the conventional video camera device, the output of the OB element is also read out once every field period. More specifically, as shown in FIG. 5C, the video signal is read out between the signals in the horizontal synchronization signal HD, that is, once every 1H (horizontal synchronization) period.
At this time, the horizontal black reference HOB signal is read only once each time each video line is read in the horizontal direction. on the other hand,
Data is transferred in the vertical direction within one field period, and in this vertical transfer, the vertical black reference VOB signal is read only once.

Incidentally, in a general CCD image sensor, a so-called smear phenomenon occurs when the photoelectric conversion element receives strong light. The smear phenomenon is that the photoelectric conversion element receives an intense light and the element becomes saturated early, which affects the surrounding photoelectric conversion element and the vertical transfer of electric charge, and a portion of the captured image where excessive light is received. , Or a phenomenon in which bleeding or lines occur in the vertical and vertical directions. Since the influence of the smear phenomenon affects OB elements to which light is not originally applied, the occurrence of the smear phenomenon can be detected by detecting the OB data.

[0010]

However, as described above, in the conventional CCD image sensor, the smear phenomenon is detected by reading the OB data once every one field period. At this interval, sufficient detection accuracy could not be obtained, and it was difficult to sufficiently prevent image quality deterioration.

In particular, in high-speed imaging in which reading of the photoelectric conversion element is performed a plurality of times in one field period to capture a plurality of images in one field period, in the conventional method, one vertical black reference is used. Smear detection or the like of a plurality of images is performed, and there is a concern that the accuracy of the clamping process may be reduced.

The present invention has been made in view of the above-mentioned problems, and aims to prevent deterioration of an image caused when smear due to high luminance data occurs in an image pickup device such as a CCD and improve image quality. It is an object of the present invention to provide an imaging device capable of performing the above.

[0013]

According to a first aspect of the present invention, there is provided an image pickup apparatus comprising: a plurality of photoelectric conversion elements for detecting light; The solid-state imaging section includes one or more rows arranged in a horizontal direction. An optical vertical black reference detecting element configured so as not to receive light by the photoelectric element for one minute, and reading out each of the photoelectric conversion elements a plurality of times within one field period, and within one field period Each time the reading is performed a plurality of times, the electric charge of the vertical black reference detecting element is read.

According to the imaging apparatus of the first aspect, every time the image is read out a plurality of times during one field period, the readout is also performed on the vertical black reference detecting element. Smear and the like can be detected, and the clamp process can be performed with high accuracy.

According to a second aspect of the present invention, in the imaging device according to the first aspect, the photoelectric conversion element is shielded so as not to receive light, and includes at least the vertical black reference detecting element. A device is provided in the solid-state imaging unit, and a detection unit for detecting an output from the black reference detection device in the solid-state imaging unit is provided, and reading of each of the photoelectric conversion elements is performed a plurality of times within one field period. Based on the detection result of the means, the electric charge of the vertical black reference detecting element within one field period is varied to 0 times or the number of reading times of the photoelectric conversion element or less.

According to the imaging apparatus of the second aspect, the image is read a plurality of times within one field period, and the reading of the element for detecting the vertical black reference is performed based on the detection result of the detecting means. (1) Since the number of times of image reading is variably changed from 0 in one field period, the number of times of reading based on the vertical black can be adjusted as needed, and the clamping process according to various imaging modes and imaging conditions can be performed. Etc. can be performed.

Thus, for example, the number of times of reading based on the vertical black can be changed between normal times and when smear or the like occurs, and a balance between the number of effective lines at the time of imaging and the accuracy of the clamping process can be made according to the situation. Can be adjusted appropriately.

In the image pickup apparatus according to the second aspect, when the number of times of reading the vertical black reference is set to 0, reading of the vertical black reference and signal processing can be omitted.
Video signal processing can be speeded up.

According to a third aspect of the present invention, in the imaging system according to the first or second aspect, when a captured image is displayed, a signal from the vertical black reference detecting element is displayed. When it is present in the image, it has shielding means for shielding the signal present in the image.

According to the imaging apparatus of the third aspect, by blanking the black reference existing in the display screen, for example, the value of the signal is set to 0, and the vertical black reference moves into the screen. Can be prevented, and the vertical black reference can be prevented from affecting the adjustment of, for example, white balance, iris, focus, and the like.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. The imaging device according to the present invention can be applied to a video camera device.

[Configuration of Imaging Apparatus] A video camera apparatus 100 according to an embodiment of the present invention includes a CCD image sensor 1 for capturing an image of a subject as shown in FIG.
A CDS / AGC2 that removes noise components from the image pickup signal from the image sensor 1 by using a correlated double sampling method, amplifies the noise component with an appropriate gain, and outputs the amplified signal;
It has an ADC 3 for converting an image pickup signal from the S / AGC 2 into a digital signal, and a DSP 4 for subjecting an output from the ADC 3 to a predetermined video process process and the like and outputting the result.

The video camera device 100 has a D
A memory 5 for temporarily storing an image pickup signal from the SP 4; a recording / reproducing unit (VTR) 7 for recording and reproducing the image pickup signal from the DSP 3 on a video tape;
A switch 11 for selecting and outputting an image signal from the memory 6 during reproduction and selecting and outputting an image signal reproduced by the recording / reproducing unit 7; and a memory control unit 5 for controlling storage and reading of the memory 6. are doing.

Further, the video camera device 100
A display unit 8 that displays an image corresponding to an image pickup signal supplied from the DSP 4 and an image reproduced by the recording and reproduction unit 7, for example, an electronic viewfinder or a small liquid crystal monitor.
An external output terminal 10 for supplying an image signal to an external monitor device such as a television receiver, and a method of variably controlling a method of reading electric charges stored in the CCD image sensor 1 during recording according to an image capturing mode. And a control unit 9 for controlling the reproduction state of the recording / reproduction unit 7 during reproduction.

In the video camera device 100, at the time of imaging (at the time of recording), the terminals 11b and 11c of the switch 11 are connected, and the output from the CCD 1 is transmitted via the memory control unit 5 to the display unit. While displaying an image on the monitor 8 or a monitor device, the imaging signal is recorded on the VTR 7, and at the time of reproduction, the terminals 11 a and 11 c of the switch 11 are connected and the imaging signal recorded on the VTR 7 is stored in the memory control unit 5. And display it on a monitor device or the like via the display unit 8 or the external output terminal 10.

The above-described CCD image sensor 1 is similar to that shown in FIG.
And a solid-state imaging unit 17 in which a large number of photoelectric conversion elements are arranged in a row direction and a column direction (two-dimensional matrix) as shown in FIG. Is output.

That is, in the CCD image sensor 1, after the electric charges accumulated by the photoelectric conversion elements in the solid-state imaging section 17 are vertically transferred to the horizontal transfer paths 22 via the respective vertical transfer paths 21, the charges are horizontally transferred in the horizontal transfer paths 22. The data is transferred to the CDS / AGC 2 via the amplifier 23 and the output terminal 24. The CCD image sensor 1 is provided with a drain means (not shown) for sweeping out unnecessary charges when capturing a plurality of images within one field period in a high-speed imaging mode described later. .

In the present embodiment, the solid-state imaging unit 17 includes an effective image area 12 for receiving an optical image and capturing an image, and a photoelectric conversion element disposed around the effective image area 12. Black reference detection elements VOB13,14 for detecting an optical black reference, which is shielded by, for example, aluminum or the like, and a horizontal black reference detection element HOB1.
5 and 16.

The VOBs 13 and 14 are formed by shielding photoelectric conversion elements horizontally arranged at the uppermost and lowermost stages of the solid-state image pickup unit 17 and detecting a vertical black reference in the effective image area 12. It is. Also, HOB1
Reference numerals 5 and 16 denote photoelectric conversion elements arranged vertically on the left and right sides of the solid-state imaging unit 17, and detect a horizontal black reference in the effective image area 12.

As shown in FIG. 3A, the DSP 4 includes a blanking means BLK25 for setting the values of the VOB signal and the HOB signal to 0 among the signals supplied to the DSP 4, and a video signal. Automatic control means AUTO 26 for automatically adjusting the white balance, iris (aperture), focus, etc. of the microcomputer, and a microcomputer 2 for processing a video signal based on the output from the AUTO 26 and outputting it to the DSP 4
7 are provided.

[Operation at the Time of Imaging] Next, the operation of the video camera apparatus 100 according to the present embodiment having the above-described configuration will be described. The video camera apparatus 100 includes a “normal imaging mode” in which the reading of the photoelectric conversion elements of the solid-state imaging unit 17 is performed only once within one field period,
A “high-speed imaging mode” that is performed a plurality of times during a field period is provided.

(Operation in Normal Imaging Mode) In this normal imaging mode, the photoelectric conversion element is read only once in one field period, and the VOB signal is read only once in one field period. That is,
In the normal imaging mode, reading is performed for all photoelectric conversion elements of the solid-state imaging device 17 once in one field period, that is, at 1/60 second intervals, and one image is captured in one field period. Note that the HOB signal is output every time each line of the image is read when reading the photoelectric conversion element.

(Operation in High-Speed Imaging Mode) In this high-speed imaging mode, reading of the photoelectric conversion element is performed a plurality of times in one field period, and a plurality of images are captured in one field period. In the present embodiment, for example, twice in one field period, that is, at an interval of 1/120 second,
Reading is performed for all photoelectric conversion elements of the solid-state imaging device 17, and two images are captured in one field period.

For reading out the VOB in the high-speed imaging mode, the following modes can be adopted.

Embodiment 1 in High-Speed Imaging Mode In this embodiment, VOB is not normally read out.
Imaging is performed by using the effective lines to the maximum. At this time,
Detection of an abnormal value due to smear or the like is performed based on only the HOB signal.

When the DSP 4 detects an abnormal value in the HOB signal, the DSP 4 notifies the TG 91 of the abnormal value. In response, the TG 91 controls the driving of the CCD 1, the CDS / AGC 2 and the ADC 3 to thereby control the VOB signal. Change the reading method.

As shown in FIG. 3B, the method of reading the VOB signal is to read the VOB signal once in one field period and to clamp two images with one VOB signal. 3C, a VOB signal is read out every time an image is read out a plurality of times (two times in this embodiment) in one field period, and one VOB signal is read for one image. There is a method of performing a clamping process.

In the method shown in FIG.
VOB after smear detection and clamp processing by P4
Since the signal becomes unnecessary, the value of the VOB signal is set to 0 by generating a blanking pulse from BLK25.
Then, a signal is sent to the AUTO 26 or the microcomputer 27.

On the other hand, in the method shown in FIG.
After smear detection and clamping by DSP4,
Since the VOB signal becomes unnecessary, it is preferable to perform blanking by the BLK25. In particular, in this method, the VOB signal is read a plurality of times, so
Since the signal is present in the screen, AUTO 26
In such a case, the blanking pulse is generated by the BLK 25 so as to blank the VOB signal existing in the screen because there is a possibility that the white balance adjustment may be affected.

These methods may be appropriately selected by the DSP 4 as necessary, for example, according to the degree of generated smear, or may be selected by the operator.

According to the first embodiment, usually V
Since the reading of the OB signal is not performed, the transfer and processing of the signal can be performed at a correspondingly high speed, the number of effective lines can be maximized, and a high-quality image can be captured. Then, when smear or the like occurs, the two methods are selected, so that the VOB signal can be read out as many times as necessary, and the accuracy of the clamping process can be adjusted according to the situation.

Embodiment 2 in High-Speed Imaging Mode In this embodiment, usually, as shown in FIG.
The VOB signal is read out only once in one field period. That is, in one field period, detection of smear or the like is performed with one VOB signal for two images.
At this time, after detecting smear by DSP4, AU
Since TO26 does not require a VOB signal,
The signal signal is blanked by the BLK25.

The DSP 4 uses a VO by smear or the like.
When an abnormal value of the B signal is detected, the abnormal value is notified to the TG 91, and in response to this, the TG 91 sets the CCD 1, CDS / AG
By controlling the driving of C2 and ADC3, VO
The B signal is output a plurality of times in one field period.
By reading out the VOB signal twice within one field period, two VOB signals are made to correspond to two images. Also at this time, as described above, the BLK25 is set so as to blank the VOB signal existing in the screen.
Generates a blanking pulse.

According to the second embodiment, usually V
By setting the number of OB signals to one, the readout period required for the VOB signal can be used for video imaging, and the number of effective video lines can be increased. In this embodiment, since smear is normally detected at least once within one field period by the VOB signal, processing for preventing smear is quickly performed when an abnormality such as smear occurs. You can start. In addition, when smear or the like occurs, by increasing the number of VOB signals, it is possible to improve the accuracy of the clamp process, and it is possible to suppress image deterioration due to smear or the like.

[Modification] The above-described video camera apparatus 10
For 0, the following modifications can be made.
That is, in the case of the high-speed imaging mode in which the image is read a plurality of times within one field period in the above-described embodiment, the image blur correction is performed by starting the reading in the solid-state imaging unit 17 from an arbitrary photoelectric conversion element. be able to.

More specifically, when capturing a plurality of images within one field period, the camera shake detection means (not shown) provided in the video camera apparatus 100 detects the tilt of the apparatus and vibrations up, down, left and right. Thus, the relative movement of the subject with respect to the video camera device 100 is calculated, and the photoelectric conversion element from which reading is started is changed based on the calculation result.

For example, when the video camera device 100 is tilted so that the CCD 1 moves upward, the subject moves downward on the imaging screen. In order to cope with this, as shown in FIG. 4, the movement of the subject can be canceled by shifting the photoelectric conversion element from which reading is started downward and moving the effective image gill downward.

Also in this case, by adopting the embodiment in the high-speed imaging mode as described above, it is possible to appropriately perform smear detection, clamp processing, and the like according to the situation, thereby improving the captured image. be able to.

[0049]

According to the imaging means of the present invention, in an imaging apparatus having a CCD image sensor such as a video camera apparatus, for example, when a high-speed mode in which an image is read a plurality of times within one field period is adopted. In addition, it is possible to appropriately prevent image degradation that occurs when an abnormality occurs in an imaging signal such as smear due to high luminance data in accordance with each imaging mode, thereby improving image quality.

[Brief description of the drawings]

FIG. 1 is a block diagram schematically showing a video camera device according to an embodiment to which an imaging device according to the present invention is applied.

FIG. 2 is a diagram showing a configuration of a CCD image sensor provided in the video camera device of the embodiment.

FIGS. 3A and 3B are explanatory diagrams showing an operation of the video camera device according to the embodiment at the time of imaging, FIG. 3A is a block diagram at the time of operation, and FIGS. 3B and 3C are VOBs in a high-speed imaging mode; 5 is a timing chart illustrating a signal reading mode.

FIG. 4 is a view showing a modification of the embodiment;
FIG. 3 is a diagram schematically illustrating an effective image area of the solid-state imaging device.

FIG. 5 is an explanatory diagram of a conventional video camera device;
(A) is a block diagram thereof, (b) is a diagram schematically showing an image pickup signal, and (c) is a time chart of the image pickup signal.

[Explanation of symbols]

1: CCD image sensor, 2: Correlated double sampling / automatic gain controller (CDS / AGC), 3: Analog
Digital conversion (ADC), 4 ... Digital signal processor (DSP), 13,14 ... VOB, 15,16 ... H
OB, 21: vertical transfer path, 22: horizontal transfer path, 23: amplifier, 25: BLK, 26: AUTO, 27: microcomputer, 91: TG

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/232 H01L 27/14 BF term (Reference) 2H002 CC21 DB01 DB19 EB00 FB51 GA11 GA33 GA46 GA54 HA05 HA07 JA08 ZA03 4M118 AA05 AB01 BA10 DB01 DD09 FA06 GB09 GB11 5C022 AA00 AA14 AB03 AB33 AC01 AC42 AC69 AC78 5C024 AA01 BA00 CA04 CA18 DA01 FA01 GA17 GA22 GA26 GA43 GA52 HA03 HA07 HA10 HA14 HA24 JA01 JA21 JA28

Claims (3)

[Claims] 1. A solid-state imaging unit having a large number of photoelectric conversion elements for detecting light arranged in a grid in a row direction and a column direction.
In an imaging device for transferring and accumulating charges accumulated by light reception by these photoelectric conversion elements, the solid-state imaging unit shields one or more rows of the photoelectric elements arranged in a horizontal direction so as not to receive light. An optical vertical black reference detecting element configured by: reading each photoelectric conversion element a plurality of times during one field period; and performing the reading performed a plurality of times during one field period; An imaging device for reading out charges from a vertical black reference detecting element. 2. The imaging device according to claim 1, wherein the photoelectric conversion element is configured to block light so as not to receive light, and a black reference detection element including at least the vertical black reference detection element is used as the solid-state imaging unit. And a detecting means for detecting an output from the black reference detecting element in the solid-state imaging unit. The reading of each of the photoelectric conversion elements is performed a plurality of times within one field period, and based on a detection result of the detecting means. An image pickup apparatus, wherein the electric charge of the vertical black reference detecting element in one field period is changed to 0 times or the number of reading times of the photoelectric conversion element or less. 3. The image pickup apparatus according to claim 1, wherein when a picked-up image is displayed, a signal from the vertical black reference detecting element is present in the displayed image. An imaging apparatus comprising: a shielding unit that shields the signal present in an image.