JPH0583730A - Color video camera - Google Patents

Abstract

PURPOSE:To obtain the color video camera in which a color signal whose white balance is properly kept over a wide dynamic range is outputted. CONSTITUTION:A color image pickup section 10 employing 2-line simultaneous read type CCD (charge coupling device) image sensors 15R, 15G, 15B is controlled by an image pickup control section 60 to implement image pickup by selecting the exposure condition for each field. The operation of a level control section 20 receiving each color pickup signal obtained by the color image pickup section 10 is controlled by a white balance control section 70 to select adaptively the white balance for each field, and the field processing section 30, the process processing section 40 and an encode processing section 50 produce a color image pickup output signal from each color image pickup signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup signal of an odd field image from a photoelectric conversion section for photoelectrically converting light information in pixel units and accumulating and outputting a plurality of pixel information obtained by the photoelectric conversion for a predetermined time. Also, the present invention relates to a color video camera using a 2-line simultaneous readout type solid-state image sensor in which an image pickup signal of an even field image is read out for each field. The present invention relates to a color video camera capable of obtaining an image output having a wide dynamic range.

[0002]

2. Description of the Related Art CCD (Charge Coupled)
A solid-state image sensor such as a device (charge-coupled device) image sensor has excellent features such as no image sticking or afterimage, high impact resistance, and easy miniaturization of a camera, compared with an imaging tube. There is. Generally, in a video camera conforming to a standard television system such as the NTSC system in which interlaced scanning is adopted, an image pickup signal from each pixel of an odd field image and an image pickup signal from each pixel of an even field image are recorded for one field period ( In the NTSC system, a CCD image sensor is used which is read alternately every 1/60 sec. In addition, a so-called Progressing Scan C is provided in which a horizontal transfer register for two lines is provided to read out the image pickup signals from each pixel of the odd field image and the image pickup signals from each pixel of the even field image within one field period.
A CD (hereinafter referred to as PS CCD) image sensor is provided for a high-resolution video camera.

[0003]

By the way, in the conventional video camera, as shown in FIG.
Within a narrow range of 90% to 110% of the signal level of
A method of expanding the dynamic range by a non-linear process for level-compressing a wide dynamic range component of about 90% to 600% of the CD output Co has been generally adopted.
However, in such an expansion method, since the processing is performed in a non-linear manner, there is a limit to the expansion of the dynamic range, and there is a problem that the gradation of the CCD output Co in the Z range shown in FIG. 4 cannot be obtained. .. That is, since 90% to 600% of the CCD output Co can be expressed only at a level of 90% to 110%, for example, the illumination condition of an object such as an indoor scene with an outdoor scene through a window is extremely extreme. If it is different from the above, when the iris adjustment (lens diaphragm) is performed with emphasis on the indoor contrast, the outdoor scene becomes almost overexposed.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a color video camera which outputs a color image pickup signal in which a white balance is properly maintained in a wide dynamic range.

[0005]

In order to solve the above-mentioned problems, a color video camera according to the present invention photoelectrically converts optical information on a pixel-by-pixel basis, and outputs a plurality of pixel information obtained by the photoelectric conversion for a predetermined time. A color image pickup unit using a two-line simultaneous read-out type solid-state image sensor in which an image pickup signal of an odd field image and an image pickup signal of an even field image are read out for each field from a photoelectric conversion unit that accumulates and outputs, and the color image pickup unit. Of the exposure control unit for switching the exposure condition for each field, and the white balance for each field in association with the switching of the exposure condition for each field by the exposure control unit with respect to each color imaging signal obtained by the color imaging unit. Read from the white balance control unit that controls switching to the A first field memory for storing one field of each color image pickup signal of the odd field image, and a second field for storing one field of each color image pickup signal of the even field image read from the solid-state image sensor of the color image pickup section. The memory, the first level comparison means for comparing the signal level of the green image pickup signal of the odd-numbered field image simultaneously read out from the solid-state image sensor of the color image pickup section with the reference level, and the first level comparison means. Controlled by comparison output, each color image pickup signal of the odd field image read from the solid-state image sensor and each color image pickup signal of the odd field image one field before read from the first field memory are switched and output. Switching means and the second field memo The solid-state image is controlled by the second level comparing means for comparing the signal level of the green image pickup signal of the even field image read one field before from the reference level and the comparison output by the second level comparing means. Second switching means for switching and outputting each color image pickup signal of the even field image read from the sensor and each color image pickup signal of the even field image read one field before read from the second field memory, and the first switching. The image pickup signals for each color of the odd field image output through the means and the image pickup signals for each color of the even field image output through the second switching means are alternately selected for each field to output the color image pickup output signal. And a camera output generation unit that generates the image.

[0006]

In the video camera according to the present invention, the color image pickup section using the two-line simultaneous read-out type solid-state image sensor switches the exposure condition for each field to perform image pickup. For example, the first and second field modes are set. As a field having a long exposure time and a field having a short exposure time, an exposure state suitable for capturing a relatively dark image and an exposure state suitable for capturing a relatively bright image are provided.
The exposure condition is switched for each field to perform imaging, and the white balance is adaptively switched for each field to obtain each color imaging signal having different exposure conditions.
Further, two lines are simultaneously read out from the solid-state image sensor, and the color image pickup signals of each field are stored in the first and second field memories, and the video signal of each color image pickup signal under the exposure condition suitable for picking up the dark image is stored. The high-brightness part is detected, and the high-brightness part is replaced by each color image pickup signal under the exposure condition suitable for picking up the bright image by the first or second switching means. Then, the camera output generation unit outputs one field of each color image pickup signal of the odd field image output through the first switching unit and each color image pickup signal of the even field image output through the second switching unit. They are selected alternately for each and output as a color imaging output signal.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a three-chip CC according to an embodiment of the present invention.
It is a block circuit diagram which shows schematic structure of a D color video camera.

The color video camera shown in FIG.
2 line simultaneous readout type CCD image sensor 1
Color image pickup unit 10 using 5R, 15G and 15B, and CCD image sensors 15R and 1 of the color image pickup unit 10
Level control unit 20 for controlling the signal levels of the respective color image pickup signals S _RO , S _RE , S _GO , S _GE , S _BO , and S _BE read simultaneously from 5G and 15B, and supplied via this level control unit 20. Each color image pickup signal S _RO , S _RE , S _GO ,
Each color image signal S for each field from S _GE , S _BO , S _BE
R, S _G, S field processing unit 30 for generating a _B, each color image signal S _R for each field generated by the field processing unit 30, S _G, processing section 40 which processes the process performed in S _B, this process From the color image signals S _R , S _G , and S _B processed by the processing unit 40, the color imaging output signal S conforming to the standard television system is output.
_The encoding processing unit 50 that generates _OUT , the imaging control unit 60 that controls the operation of the color imaging unit 10, the imaging signals S _RO and S _{RE of} each color obtained by the color imaging unit 10,
The white balance control unit 70 controls the operation of the level control unit 20 so as to achieve the white balance of S _GO , S _GE , S _BO , and S _BE , and further includes a synchronization signal generation unit 80 that generates a synchronization signal.

The color image pickup section 10 includes an image pickup lens 1
1, an aperture mechanism 12, and an image pickup optical system 14 including a three-color separation prism 13, and in the image pickup optical system 14, the image pickup light incident through the image pickup lens 11 and the diaphragm mechanism 12 has the three-color separation prism 13. The color image is separated into the three primary colors R, G, B, and the red image, the green image, and the blue image by the three primary colors R, G, B components are each CCD image sensor 1.
Images are formed on the image pickup surfaces of 5R, 15G, and 15B.

As shown in FIG. 2, each CCD image sensor 15R, 15G, 15B used in the color image pickup section 10 has a photodiode such as a photodiode corresponding to each pixel of an odd field image and an even field image on the image pickup surface. Two horizontal transfer registers H are provided for storing charges accumulated by photoelectric conversion units SO and SE in which photosensitive elements are arranged in a matrix.
By reading two lines simultaneously through O _REG and HE _REG , all pixels, that is, one frame (2
A two-line simultaneous read-out type P.I. S. The CCD image sensor 15 is used.

This P. S. With a CCD image sensor,
The accumulated charges obtained by the photoelectric conversion action of each photosensitive element in the photoelectric conversion units SO and SE, that is, pixel information, is transferred through the vertical transfer register V _REG to the horizontal transfer register HO _REG and the even field image for the output of _{picking up} an odd field image. _Is transferred to the horizontal transfer register HE _REG for image pickup output of, and the image pickup signal S _O of the odd-numbered field image and the image pickup signal S _E of the even-numbered field image within one field period via the horizontal transfer registers HO _REG and HE _REG. , Are output at the same time.

Further, each CCD image sensor 15 described above
P. used for R, 15G, and 15B. S. The CCD image sensor 15 has an electronic shutter function. This electronic shutter function is to obtain the same effect as the shutter of a film camera by changing the accumulation time of the pixel information. Pixel information is usually accumulated for 1/60 seconds determined by the NTSC system, but according to the electronic shutter function, the shutter speed (1/200
Only 0 seconds, 1/1000 seconds ...) are accumulated.

The color image pickup section 10 includes a diaphragm mechanism 12 and CCD image sensors 15R and 15R.
The G and 15B are controlled by the imaging control unit 60, and the exposure condition is switched for each field to perform imaging. For example, the first and second field modes are set as a field having a long exposure time and a field having a short exposure time, respectively, and an exposure state suitable for capturing a relatively dark image and an exposure state suitable for capturing a relatively bright image. Further, the exposure condition is switched for each field, and image pickup is performed. As a result, as shown in FIG. 3, the image pickup signals S _O and S _E are such that a field having a high signal level and a field having a low signal level are alternately repeated in the first and second field modes, respectively. Become. Here, the period of the first field mode is an odd field, and the period of the second field mode is an even field. It should be noted that the symbol P in FIG. 4 corresponds to an outdoor scene through a window with high brightness, and the symbol Q corresponds to an indoor scene with low brightness.

Further, the level control unit 20 includes the solid-state image sensors 15R, 15G, and
Image pickup signal S of each color read simultaneously from 2 lines from 15B
_{RO, S RE, S GO,} S GE, S BO, S BE 6 amino voltage controlled that is supplied variable gain amplifier 21R _O, 21R _E, 21G
_O, 21G _E, 21B _O, consisting of 21B _E. Each voltage controlled variable gain amplifier 21R _O, 21R _E, 21
_{G O, 21G E, 21B O} , among 21B _E, green image signal S of the solid image sensor 15G for green imaging _GO, the voltage controlled variable gain amplifier S _GE is supplied 2
The gains of 1G _O and 21G _E are fixed, and the green image pickup signal S _RO of the solid-state image sensor 15R for red image pickup is obtained.
Each voltage controlled variable gain amplifier 21 to which S _RE is supplied
R _O, red level control signal gain 21R _E is supplied from the white balance control circuit 70 R. A solid-state image sensor 1 controlled by a GC and for capturing a red image
5B are supplied with the green image pickup signals S _BO and S _BE , and the gains of the voltage control type variable gain amplifiers 21B _O and 21B _E are supplied from the white balance control circuit 70. The solid-state image sensors 15R and 15G of the color image pickup unit 10 are controlled by the GC.
Image pickup signal S of each color read simultaneously from 2 lines from 15B
The white balance of _RO , S _RE , S _GO , S _GE , S _BO , and S _BE is set. And this level control unit 2
The image signals S _RO , S _RE , S _GO , S _GE , S _BO , and S _BE whose white balance has been set to 0 are supplied to the field processing unit 30. Further, the green image solid image sensor 15G from two line simultaneous read by green image signal S _GO for imaging, S _GE, each voltage-controlled gain-clamped in the level control unit 20 variable-gain amplifier 21G _O, 21G _E It is supplied to the imaging control unit 60 via the.

[0015] The imaging control unit 60, the specific configuration as shown in FIG. 4, the voltage controlled variable gain amplifier 21G _O of fixed gain of the level control unit 20, a green imaging supplied from 21G _E A signal adder 61 for adding the signals S _GO and S _GE is provided, and the addition output by the signal adder 61 is supplied to the common terminal of the changeover switch 63 via the buffer circuit 62. This imaging control unit 60
Is the signal adder 61 of the green image pickup signals S _GO and S _GE.
The added output of the iris control unit 64 and the shutter control unit 65 are supplied via the changeover switch 63.
Equipped with. The changeover switch 63 is a field changeover pulse FP provided by the synchronization signal generator 80.
The connection mode is switched according to. For example, when the field switching pulse FP is at the high level, the first field mode is switched to the iris control section 64 side, and when it is at the low level, the second field mode is switched to the shutter control section 65 side.

The iris control section 64 includes a switch 64.
a, a level detection circuit 64b and an error amplifier 64c, and the shutter control section 65 is composed of a level detection circuit 65a, an error amplifier 65b and a changeover switch 65c. The level detection circuit 64b
Has a time constant enough to hold the next field period.

In the first field mode, the changeover switch 65c of the shutter control section 65 is used.
Selects the reference level VC, the shutter control signal SC becomes maximum, and the shutter speed is 1 /
It will be 60 seconds. Further, the output of the signal adder 61 is given to the switch 64a via the buffer circuit 62 and the changeover switch 63. The switch 64a is turned on / off based on the control pulse CTL _O inverted by the inverter 66. The switch 64a is turned off when the control pulse CTL _{O is at} a high level and turned on when it is at a low level. Here, for the control pulse CTL _O , the image pickup signals S _O and S in the first field mode obtained by the field processing block 31B described later.
The detection pulse CTL _OG of the high brightness portion P of _E is used.

[0018] Thus, the level detecting circuit 64b is at a lower level of the control pulse CTL _O, i.e., incorporating the output of the buffer circuit 62 only for the period t _1, t ₃ shown in FIG. 3, it detects the output level. Further, the error amplifier 64c detects how much the detected level has an error with respect to the level V ₁ . Then, iris adjustment is performed so that the error becomes zero. As a result, as shown in FIG. 3, the low luminance portion Q of the image pickup signals S _O and S _E in the first field mode is set to the level V ₁ .

On the other hand, in the second field mode, the output of the signal adder 61 is supplied to the level detection circuit 65a via the buffer amplifier 62 and the changeover switch 63, and the output level thereof is detected. Further, the error amplifier 65b detects how much error the detected output level has with respect to the level V ₂ (V ₂ > V ₁ ). Then, the shutter control signal SC is supplied to the timing generator 67 via the changeover switch 65c so that the error becomes zero. The timing generator 66 outputs CCD drive pulses corresponding to the shutter control signal SC to the CCD image sensors 15R,
15G, 15B to control the electronic shutter of the CCD. As a result, the high-luminance portion P of the image pickup signals S _O and S _E in the second field mode is set to the level V ₂ .

The timing generator 67 is arranged so that each CCD image sensor 1 can change the accumulation time of the pixel information for each field (1/60 seconds) based on the shutter control signal SC having a different level for each field.
Drive control of 5R, 15G, and 15B is performed. As a result, the shutter speed changes for each field, and a field having a long exposure time (first field mode) and a field having a short exposure time (second field mode) are alternately repeated. As a result, the respective image pickup signals S _O and S _E are
As shown in FIG. 3, a field having a high signal level and a field having a low signal level are respectively the first and second fields.
The signal is alternately repeated in the field mode.
Then, in the first field mode, the level V ₁ in FIG. 3 is automatically set to an appropriate value according to the indoor lighting condition by controlling the iris adjustment described above by the imaging control unit 60. To be done. Similarly, the level V ₂ is
By controlling the electronic shutter function described above in the second field mode, the value is automatically set to an appropriate value according to the outdoor lighting condition.

As described above, the image pickup control section 60 has the first
And the second field mode as a long exposure time field and a short exposure time field,
Each of the CCD image sensors 15R, 15G, 15G, 15G, 15G, 15G Drive control of 15B is performed.

Further, the field processing section 30 is provided with the red image pickup signal S supplied through the level control section 20.
A field processing block 31R for generating a red image signal S _R for each field from _RO , S _RE , and a green image signal S _{G for} each field from the green image pickup signals S _GO , S _GE.
And a field processing block 31R that generates a blue image signal S _B for each field from the blue image pickup signals S _BO and S _BE . Each field processing block 31R, 31G, 31
Each B has a configuration as shown in FIG.

That is, as shown in FIG. 5, the field processing block 31 includes each CCD of the color image pickup section 10.
The P.C. used for the image sensors 15R, 15G, and 15B.
S. Two analog digital (A / D) converters 32 _O and 32 _{E for} digitizing the respective image pickup signals S _O and S _E which are simultaneously read out from the image sensor 15 by two lines and supplied through the level control unit 20. And these A
/ D converter 32 _O, 32 each of the image pickup signal S _O by _E, S _E
The image pickup data D _O and D _{E which} are digitized are supplied to the changeover switches 34 _O and 34 _E directly and via the field memories 33 _O and 33 _E , respectively.

Further, this field processing block 31
Is provided with a level comparator 35 _O for comparing the signal level of the image pickup signal S _O represented by the image pickup data D _O digitized by the A / D converter 32 _O with a predetermined reference level V _4, and this level comparator 35 _O switching control of the changeover switch 34 _O is performed by the comparison output by _O. Further, the field processing block 31 includes a level comparator 35 _E for comparing the signal level of the image pickup signal S _E indicated by the image pickup data D _E delayed by one field via the field memory 33 _E with the reference level V _4. The changeover switch 34 _E is controlled by the comparison output from the level comparator 35 _E. The image pickup data D _O and D _E selected by the changeover switches 34 _O and 34 _E are further output via the changeover switch 36.

The level comparator 35 _O is connected to the A
The signal level of the image pickup signal S _O represented by the image pickup data D _O digitized by the / D converter 32 _O is compared with a predetermined reference level V _4, and the signal level of the image pickup signal S _O is set to a predetermined reference level. is higher than V ₄ becomes high level (P in FIG. 3), and if smaller outputs the control pulse CTL _O as the low level.

The changeover switch 34 _O performs a changeover operation according to the control pulse S3, and when the control pulse CTL _O is at a low level, the image pickup data D digitized by the A / D converter 32 _{O. O} select, also, the control pulse S3 is at the time of high level to select the imaging data D _O before one field from the field memory 34 _O. That is, as shown in FIG. 3, the control pulse CTL _O is at a high level only during the high luminance period t2 in the first field mode, and the changeover switch 34 _O is in the high luminance period t2 in the first field mode. The imaging data D _O one field before is selected from the memory 34 _O , and the other period t
_Since the control pulse CTL _O is at a low level, the t ₁ and t ₃ select the imaged data D _O digitized by the A / D converter 32 _O.

In this way, the high-luminance portion (P in FIG. 3; camera output 100% or more) of the imaged data D _{O obtained} by digitizing the imaged signal S _O of the odd-numbered field image is at the high level of the control pulse CTL _O. And the image data D _O of the second field having a low video level can be replaced only when the image pickup signal S _{O has} a high luminance. Accordingly, the output side of the changeover switch 62 is connected to the output side of FIG.
As shown in, the level V _2, V ₂ is the imaging data D _O which is set in the odd field period is outputted.

Further, the level comparator 35 _E is
The signal level of the image pickup signal S _E indicated by the image pickup data D _E delayed by one field via the field memory 33 _E is compared with the predetermined reference level V _4, and the signal level of the image pickup signal S _E is set to the above. When it is higher than the reference level V ₄ , it becomes a high level and a large high-brightness portion (see FIG. 3).
Control pulse CTL _E , which has a high level when the camera output is 100% or more) and a low level when the output is low.
Is output.

Then, the changeover switch 34_EIs on
Control pulse CTL_EThe switching operation is performed according to
Control pulse CTL_EIs low level, the above A / D
Converter 32_EImaging data D digitized by_E
And the control pulse CTL_EIs a high level
Field memory 34_E1 fee from
Image data D before scanning_ESelect. That is, in FIG.
As shown, the high brightness period in the second field mode
Interval t₂Control pulse CTL only_EBecomes a high level and
Note switch 34_EIs the first field mode above
High brightness period t₂Only the above A / D converter 32_E
Imaging data D digitized by _ESelect
Pulse CTL_EDuring another period t when is at a low level₁, T
₃Is the field memory 34_EFrom one field before
Imaging data D_ESelect.

In this way, the high-intensity part of the imaged data D _{E obtained} by digitizing the imaged signal S _E of the odd-numbered field image is detected at the high level of the control pulse CTL _E , and the high-intensity of the imaged signal S _E is detected. Only in the case of, it is possible to replace with the imaging data D _E of the first field having a low video level. By performing the switching operation in this way,
On the output side of the changeover switch 34 _E , as shown in FIG. 3, the imaging data D _E in which the levels V ₁ and V ₂ are set within the even field period is output.

[0031] Then, 3 a switch 36 switching between the image data D _E even field obtained via the image data D _O and the changeover switch 34 _E even field obtained through the changeover switch 34 _O Like one
By switching for each field according to the field switching pulse FP which is inverted for each field, field sequential signals D ₀ / D _E corresponding to interlace scanning are formed and output.

Further, the process processing section 40 is a process processing circuit for performing a predetermined signal processing such as a synchronization signal addition processing on each color image signal S _R , S _G , S _B of each field generated by the field processing section 30. 40R, 40G,
40B, and each processed image signal S _R ,
The S _G and S _B are supplied to the encoding processing unit 50. Then, the encoding processing unit 50 generates a color image pickup output signal S _OUT compliant with the standard television system from the respective color image signals S _R , S _G , S _B processed by the process processing unit 40. Output.

The white balance control section 70 is also provided.
Are configured as shown in FIG. This white ba
In the lance controller 70, the first to third input terminals 7
1R, 71G, and 71B have the above-mentioned field processing unit 30
In each field processing block 31R, 31G, 31B
Digitalized image data D of each color_R, D_G, D
_BIs supplied, and the fourth to sixth input terminals 72R,
72G and 72B include the above field processing blocks 31
Each control pulse CTL obtained by R, 31G, 31B
_OR, CTL_OG, CTL_OBIs supplied.

The white balance control unit 70 includes a comparator 73 and an adder 74 to which the image data D _R , D _G , D _{B of} each color are supplied via the first to third input terminals 71R, 71G, 71B. Equipped with. The green image pickup data D _G is supplied to one input end of the comparator 73, and the red image pickup data D _R and the blue image pickup data D _B are selectively supplied to the other input end thereof via the switch 75.
Then, the comparator 73 determines the red image pickup data D _R and the blue image pickup data D with respect to the green image pickup data D _G.
Detect the difference of _B. The difference output from the comparator 73 is supplied to the sample hold circuit 76.

Further, the adder 74 forms level data corresponding to a luminance signal by adding the image pickup data D _R , D _G and D _B of the respective colors. Then, the addition output from the adder 74, that is, the level data corresponding to the luminance signal is passed through the switch 77 to the peak level detector 7
8 are supplied. Then, the peak level detector 78
Detects the high brightness portion of the captured image, that is, the white portion by detecting the peak level of the level data formed by the adder 74. The output detected by the peak level detector 78 is supplied to the sample hold circuit 76 as a sampling pulse.

Further, the white balance control unit 70
Includes an OR gate 79 to which each of the control pulses S3 _R , S3 _G and S3 _B is supplied via the fourth to sixth input terminals 72R, 72G and 72B. This OR gate 7
Reference _numeral 9 denotes the control pulses CTL _OR , CTL _OG , and CTL _OB described above.
Of the control pulses CTL _OR , CT
The above adder 7 is operated while L _OG and CTL _OB are all at the low level.
The switching control of the switch 77 is performed so that the addition output by 4, the level data, that is, the level data is supplied to the peak level detector 78. As a result, the peak level detector 78 is supplied with level data excluding the high luminance period in the first field having a long exposure time.

The peak level detector 78 is
Peak level detection is performed on the level data excluding the high luminance period in the first field having a long exposure time, a high luminance portion, that is, a white portion of the captured image is detected, and the detection output is used as a sampling pulse, and the sample hold circuit is used. Supply to 76. The sample hold circuit 76 samples and holds the difference output of the red image data D _R and the blue image data D _B with respect to the green image data D _G detected by the comparator 73 as error data of the white portion.

Further, the white balance control unit 70
It is the sample hold circuit 76 by the sampled and held the green imaging data D red imaging data D for _{G R} and the blue image pickup data D 4 pieces of memory 80R _H for storing the respective color error data _B, 80R _L, 80B _H, 8
Equipped with a 0B _L.

That is, the sample hold circuit 76
The sample hold output by the system controller 81 is controlled by the system controller 81 together with the switch 75 to separate the error data of the red image data D _{R and} the error data of the blue image data D _{B from} the green image data D _G. To be done. Then, the error data of the red image data D _R is supplied to each of the memories 80R _H and 80R _L via the switch 83R which is switched and controlled by the field pulse FP, and the red error data of the first field is stored in the memory 80R. It is written to _H, the red error data of the second field is written in the memory 80R _L. Further, the error data of the blue image pickup data D _B is supplied to each of the memories 80B _H and 80B _L via the switch 83B which is switched and controlled by the field pulse FP, and the blue error data of the first field is stored in the memory 80B. _It is written in _H and the blue error data of the second field is stored in the memory 8
It is written to the 0B _L.

Then, each of the memories 80R _H , 80
The color error data read from R _L , 80 B _H , and 80 B _L are the D / A converters 84R _H , 84R _L , and 84D, respectively.
A switch 85 which is analogized by B _H and 84 B _L and is switch-controlled by the field pulse FP.
It is output as each color level control signal via R and 85B.

That is, the red error data of the first field read from the memory 80R _H and the red error data of the second field read from the memory 80R _L are respectively converted by the D / A converters 84R _H and 84R _L. is an analog of, via the switch 85R is switching control by the field pulse FP, the voltage-controlled of the level control unit 20 as a red-level control signal variable gain amplifier 21R _O, it is supplied to the 21R _E. The blue error data of the first field read from the memory 80B _H and the blue error data of the second field read from the memory 80B _L are converted into analog data by the D / A converters 84B _H and 84B _L , respectively. Then, the voltage control type variable gain amplifier 2 of the level control section 20 is converted into a blue level control signal through the switch 85R which is switched and controlled by the field pulse FP.
It is supplied to 1B _O and 21B _E.

In the color video camera having such a structure, the two-line simultaneous read-out type solid-state image sensor 15 is used.
The image pickup operation by the color image pickup unit 10 using R, 15G, and 15B is controlled by the image pickup control unit 60, and the first and second field modes are set as a long exposure time field and a short exposure time field, respectively. The exposure condition is switched for each field between the exposure state suitable for capturing a dark image and the exposure state suitable for capturing a relatively bright image, and the white balance control unit 70 controls each field. Then, the white balance is adaptively switched to obtain the respective color image pickup signals having different exposure conditions. Then, the solid-state image sensor 1
Simultaneous reading of two lines from 5R, 15G, and 15B The respective color imaging signals of each field are stored in the first and second field memories 33 _O and 33 _E , and each color imaging is performed under the exposure condition suitable for imaging the dark image. The high-luminance portion of the video signal by the signal is detected, and the high-luminance portion is replaced with each color imaging signal under the exposure condition suitable for capturing the bright image. The switch 36 is the switch 34.
Each color image pickup signal of the odd field image output through _O and each color image pickup signal of the even field image output through the switch 34 _E are alternately selected for each field and output as a color image pickup output signal. This allows
Even in situations where the lighting conditions of the subject are extremely different, it is possible to obtain a color imaging output signal that does not cause overexposure as in the past and that can be reproduced with good contrast and the white balance is properly maintained in a wide dynamic range. it can.

[0043] In the color video camera in this embodiment, the manual to allow setting of the white balance due, each D / A converter 84R _H, 84R _L, 84
B _H, the level adjuster for the white balance setting by 84B _L output and manual 86R _H, 86R _L, 86
B _H, switches the output according 86B _L 87R _H, 87
It can be switched by R _L , 87B _H , and 87B _L.

[0044]

As is apparent from the above description, in the video camera according to the present invention, the color image pickup section using the two-line simultaneous read-out type solid-state image sensor switches the exposure condition for each field to pick up an image. For example, the first and second field modes are set to a field having a long exposure time and a field having a short exposure time, respectively, and an exposure state suitable for capturing a relatively dark image and an exposure suitable for capturing a relatively bright image. The exposure condition is switched for each field depending on the state and imaging is performed, and the white balance is adaptively switched for each field to obtain each color imaging signal having different exposure conditions. Further, two lines are simultaneously read out from the solid-state image sensor, and the color image pickup signals of each field are stored in the first and second field memories, and the video signal of each color image pickup signal under the exposure condition suitable for picking up the dark image is stored. The high-brightness part is detected, and the high-brightness part is replaced by each color image pickup signal under the exposure condition suitable for picking up the bright image by the first or second switching means. Then, the camera output generation unit outputs one field of each color image pickup signal of the odd field image output through the first switching unit and each color image pickup signal of the even field image output through the second switching unit. Alternately selected for each, and output as a color imaging output signal, it is possible to synchronize the video signal before the field and the current video signal to form a video signal with an equivalently expanded dynamic range. Even if the lighting condition of the subject is extremely different, such as when there is an outdoor scene through a window in an indoor scene, the outdoor scene does not become overexposed as in the past, and the contrast is good. Can be reproduced.

Therefore, according to the present invention, it is possible to provide a color video camera which outputs a color image pickup signal in which the white balance is properly maintained in a wide dynamic range.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a 3-chip CCD color video camera that is an embodiment of the present invention.

FIG. 2 is a schematic plan view showing a configuration of a CCD image sensor used in the color video camera.

FIG. 3 is a timing chart showing the operation of the color video camera.

FIG. 4 is a block diagram showing a configuration of an imaging control unit in the color video camera.

FIG. 5 is a block diagram showing a configuration of a field processing block of a field processing unit in the color video camera.

FIG. 6 is a block diagram showing a configuration of a white balance control unit in the color video camera.

FIG. 7 is a characteristic diagram for explaining a dynamic range of a conventional video camera.

[Explanation of symbols]

10: Color imaging unit 20: Level control unit 30: Field processing unit 40: Process Processing unit 50 ... Encoder 60 ... Imaging control unit 70 ... White balance control unit 80 ... Synchronous signal generator 33 _O , 33 _E ... Field memory 34 _O , 34 _E ... Changeover switch 35 _O , 35 _E ... Level comparator 36 ...

Claims (1)

[Claims] 1. An image pickup signal of an odd field image and an image pickup of an even field image from a photoelectric conversion unit that photoelectrically converts optical information in pixel units and accumulates and outputs a plurality of pixel information obtained by the photoelectric conversion for a predetermined time. A color image pickup unit using a two-line simultaneous read-out type solid-state image sensor for reading out a signal for each field, an exposure control unit for switching the exposure condition of the color image pickup unit for each field, and the color image pickup unit. Each color image pickup signal is read from a white balance control unit that controls switching of white balance for each field in conjunction with switching of exposure conditions for each field by the exposure control unit, and a solid-state image sensor of the color image pickup unit. A first filter for storing one field of each color imaging signal of an odd field image Field memory, a second field memory for storing one field of each color image pickup signal of an even field image read from the solid-state image sensor of the color image pickup section, and an odd number of two lines simultaneously read from the solid-state image sensor of the color image pickup section. First level comparing means for comparing the signal level of the green image pickup signal of the field image with a reference level, and image pickup for each color of the odd field image which is controlled by the comparison output by the first level comparing means and read from the solid-state image sensor. A first switching means for switching and outputting a signal and an image pickup signal of each color of an odd field image one field before read from the first field memory; and an even field one field before read from the second field memory. Signal of green image pickup signal of image Second level comparing means for comparing the level with the reference level, and each color image pickup signal of the even field image read from the solid-state image sensor, which is controlled by the comparison output by the second level comparing means, and the second level comparing means. Second switching means for switching and outputting each color image pickup signal of the even field image one field before which is read out from the field memory, and each color image pickup signal of the odd field image outputted via the first switching means. 1 is set for each color image pickup signal of the even field image output through the second switching means.
A color video camera, comprising: a camera output generation unit that alternately selects each field and generates a color imaging output signal.