JPH0879602A - Smear judgement system, controller for shutter and television doorphone using the controller - Google Patents

Abstract

PURPOSE: To judge a position where the smear in a video signal from a video camera unit occurs. controls an endure control circuit 28, CONSTITUTION: A smear judgement circuit 32 controls an exposure control circuit 28, detects the luminance of composite video signals cl equivalent to one screen for respective picture elements based on a horizontal synchronizing signal di, a vertical synchronizing signal el and a sampling clock signal ul in a state where the exposure time of a CCD video camera unit 46 from N-th to N+K-th fields is changed, judges that smear occurs in the position of the picture element when the rate of luminance at the time of changing exposure time is less than a prescribed value and supplies the smear judgement signal x1 of the judged result to an average luminance detection circuit 33.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention performs a smear determination system for determining smear of a video signal from a video camera unit using a charge-coupled device and exposure control of an electronic shutter of a video camera unit using a charge-coupled device. The present invention relates to a shutter control device and a TV door phone using the control device, and more particularly to a smear determination system suitable for exposure control when smear occurs, a shutter control device, and a TV door phone using the control device.

[0002]

2. Description of the Related Art In recent years, TV door intercoms having the functions of both a surveillance video camera and a parent-child intercom system have become popular with general users due to the cost reduction of image pickup devices.

In such a TV door phone, in order to make the slave unit compact, a C image pickup device is used.
Those using a CD (Charge Coupled Device) have become popular. In a TV door phone using such a CCD, automatic exposure control is performed on the video camera unit in order to cope with changes in the brightness of a subject in a high range such as day and night.

Here, in a TV door phone using a CCD, there is a case where an image of high brightness such as the sun or a headlight of an automobile is taken as a background, and in this case, charges from a photodiode serving as a light receiving portion are taken. Spills over the vertical CCD, overflows from the potential well of the vertical CCD and flows into the wells of other potentials, and a vertical bright line (generally a white level line) is generated on the screen of the monitor section. This vertical line is called smear, and this smear will be displayed on the screen with constant brightness for some time even if the exposure is changed. When such smear occurs, the brightness of the smear causes the exposure time of the electronic shutter to be controlled lower than the proper exposure of the subject such as a person the user wants to see, and the subject is displayed in black on the monitor. Will be done.

[0005]

In the above-mentioned conventional technique, when smear occurs, the exposure time of the electronic shutter is appropriate for proper exposure of the subject such as a person the user wants to visually recognize due to the brightness of the smear. It is controlled to be low, and the subject is displayed in black on the monitor.

Therefore, the present invention aims to eliminate the above-mentioned problems and to provide a smear judging system capable of judging the position where the smear of the video signal from the video camera unit occurs, and in the case where the smear occurs. Also, it is an object of the present invention to provide a shutter control device capable of obtaining proper exposure and a television door phone using the control device.

[0007]

According to a first aspect of the present invention, there is provided a smear determination system including a video camera unit for capturing an image using a charge-coupled device and outputting a video signal, and exposure control of an electronic shutter of the video camera unit. And an exposure control circuit for performing predetermined conditions, the exposure control circuit is controlled for a predetermined period to detect the brightness of the video signal from the video camera unit in a state where the exposure time is gradually reduced. And a smear determination circuit for determining the position of the video signal in which the rate of change in luminance is equal to or less than a predetermined value during the predetermined period as the position where smear occurs.

According to a second aspect of the present invention, there is provided a shutter control device, which includes a video camera unit for capturing an image using a charge-coupled device and outputting a video signal, and an exposure control circuit for controlling the exposure of an electronic shutter of the video camera unit. When the predetermined condition is satisfied, the brightness of the video signal from the video camera unit is detected in a state where the exposure control circuit is controlled to decrease the exposure time stepwise during the predetermined period, and the predetermined time period is detected. In the smear determination circuit that determines the position of the video signal where the rate of change in luminance is less than or equal to a predetermined value as the position where smear occurs, and the position of the smear determined by the smear determination circuit from the video signal from the video camera unit. Of the remaining video signal is detected, the exposure control circuit is controlled based on the detection result, and the average brightness of the remaining video signal is detected. Characterized by comprising the average luminance detection circuit for performing exposure control of the electronic shutter of Deo camera unit.

According to a fifth aspect of the present invention, there is provided a smear determination system, which includes a video camera unit for capturing an image using a charge-coupled device and outputting a video signal, and an exposure control circuit for controlling the exposure of an electronic shutter of the video camera unit. ,
Comparing the brightness of the video signal from the video camera unit with a predetermined level and outputting a comparison detection signal indicating whether or not the brightness of the video signal exceeds the predetermined level, and a comparison from the comparator 1 for detection signal
A field memory that stores one field and outputs a one-field delay comparison and detection signal by reading the comparison and detection signal after one field has elapsed, and a one-field delay comparison and detection signal from this field memory and the above-mentioned comparator When both the comparison detection signal and the comparison detection signal indicate that the luminance exceeds a predetermined level, the first level output is performed, and the 1-field delay comparison detection signal from the field memory and the comparison detection signal from the comparator are output. A logic circuit that outputs a second level when at least one of the following shows that the brightness has not exceeded a predetermined level; and the exposure control circuit during a predetermined period when a predetermined condition is satisfied. The output from the logic circuit is detected while controlling the exposure time for each field to decrease. The video signal from the video camera unit corresponding to the position where the output from the logic circuit becomes the second level after a predetermined field from the change in the output from the logic circuit for one field in the predetermined period And a smear position determination control circuit for determining the position as a position where smear occurs.

According to a sixth aspect of the present invention, there is provided a shutter control device which comprises a video camera unit for taking an image using a charge coupled device and outputting a video signal, and an exposure control circuit for performing exposure control of an electronic shutter of the video camera unit. And a comparator that compares the brightness of the video signal from the video camera unit with a predetermined level and outputs a comparison detection signal indicating whether or not the brightness of the video signal exceeds the predetermined level, and the comparator. 1 field delay comparison detection signal from this field memory, and a field memory for storing 1 field delay comparison detection signal by storing the 1 field delay comparison detection signal In both the signal and the comparison detection signal from the comparator, the luminance has a predetermined level. Perform the output of the first level when indicated that beyond the Le, 1 from the field memory
A logic circuit that outputs a second level when the luminance does not exceed a predetermined level in at least one of the field delay comparison detection signal and the comparison detection signal from the comparator, and a predetermined condition. Is satisfied, the exposure control circuit is controlled for a predetermined period to detect the output from the logic circuit while the exposure time is reduced for each field, and the logic circuit for one field is detected for the predetermined period. After a predetermined field from the change in the output from the video signal, the position of the video signal from the video camera unit corresponding to the position where the output from the logic circuit becomes the second level is determined to be the position where the smear is generated. A video signal of the position of the smear determined by the position determination control circuit and the smear position determination control circuit from the video signal from the video camera unit. And an average brightness detection circuit for detecting the average brightness of the remaining video signal and controlling the exposure control circuit based on the detection result to control the exposure of the electronic shutter of the video camera unit. Characterize.

[0011]

According to the structure of the present invention, the smear determination circuit detects the brightness of the video signal from the video camera unit in a state where the exposure time is gradually reduced in a predetermined period, and in the predetermined period. By determining the position of the video signal in which the rate of change in luminance is equal to or less than a predetermined value, the position where the smear of the video signal from the video camera unit occurs can be determined.

According to the second aspect of the invention, the smear determination circuit detects the brightness of the video signal from the video camera unit in a state in which the exposure time is gradually reduced in a predetermined period, and in the predetermined period. The position of the video signal in which the rate of change in luminance is equal to or less than a predetermined value is determined to be the position where smear occurs, and the average luminance detection circuit determines the smear of the smear determined by the smear determination circuit from the video signal from the video camera unit. When smear occurs, the position video signal is removed, the average brightness of the remaining video signal is detected, and the exposure control circuit is controlled based on the detection result to control the exposure of the electronic shutter of the video camera unit. Even a proper exposure is obtained.

According to the fifth aspect of the present invention, the smear position determination control circuit controls the exposure control circuit for a predetermined period to detect the output from the logic circuit while the exposure time is reduced for each field. The image from the video camera unit corresponding to the position where the output from the logic circuit becomes the second level after a predetermined field from the change in the output from the logic circuit for one field during the predetermined period By determining the position of the signal, the position where the smear of the video signal from the video camera unit occurs can be determined.

According to the sixth aspect of the invention, the smear position determination control circuit controls the exposure control circuit for a predetermined period to detect the output from the logic circuit in a state where the exposure time is reduced for each field. The video signal from the video camera unit corresponding to the position where the output from the logic circuit becomes the second level after a predetermined field from the change in the output from the logic circuit for one field during the predetermined period. Is determined as the position where smear has occurred, the average luminance detection circuit removes the video signal at the smear position determined by the smear position determination control circuit from the video signal from the video camera unit, and removes the remaining video signal. The average brightness is detected, and the exposure control circuit is controlled based on the detection result to control the exposure of the electronic shutter of the video camera unit. There aptitude exposure can be obtained even in the case that occurred.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a smear determination system, a shutter control device and a TV door phone using the control device according to the present invention.

In FIG. 1, the TV intercom 10 has a structure in which a parent device 20 which is a first device and a child device 40 which is a second device are connected by a pair of two-wire type wirings 11 and 12. Has become.

First, the base unit 20 will be described.

The wiring connection terminals 21 and 22 of the parent device 20 are connected to the wiring connection terminals 41 and 42 of the child device 40 through the wirings 11 and 12, respectively.

The wiring connection terminal 22 of the master device 20 is
It is connected to the reference potential point of.

The handset 23 is provided with a microphone and a speaker, and an audio signal a from an audio circuit 24 which will be described later.
1 is output from the speaker, and the audio signal b1 received by the microphone is guided to the audio circuit 24.

The audio circuit 24 uses the hybrid transformer to detect the various signals led to the wiring connection terminal 21 from the slave unit 4.
The 0-side audio signal a1 is separated, amplified, and guided to the handset, and the hybrid transformer guides the audio signal b1 from the handset 23 to the wiring connection terminal 21.

The input terminal of the signal separation / demodulation circuit 25 is connected to the wiring connection terminal 21 of the master device 20, and various signals guided to the wiring connection terminal 21 are modulated by a composite circuit from a transmission circuit 47 described later. The video signal is separated and demodulated to produce a composite video signal c1 which is a sync signal separation / video signal processing circuit 26, a smear determination circuit 32, and an average luminance detection circuit 3.
Supply to 3.

Sync signal separation and video signal processing circuit 26
Synchronizes the supplied composite video signal c1 with the synchronizing signal and guides both the horizontal synchronizing signal d1 and the vertical synchronizing signal e1 to the monitor unit 27, the smear judging circuit 32 and the average luminance detecting circuit 33, and samples the horizontal synchronizing signal d1. In addition to being guided to the clock generation circuit 31, the composite video signal c1 is subjected to blanking processing or the like to generate a video signal f1 for display and guided to the monitor unit 27. Sampling clock generation circuit 31
Generates a sampling clock signal u1 having a frequency that is a total number of horizontal pixels times the frequency of the supplied horizontal synchronization signal d1 (800 times in the case of the present embodiment), and monitors the monitor unit 27, the smear determination circuit 32, and the average luminance detection circuit. 33. The monitor unit 27 compares the supplied video signal f1 with the vertical synchronization signal e.
1 and the sampling clock signal u1 to perform sampling, perform horizontal and vertical scanning based on the supplied horizontal synchronization signal d1 and vertical synchronization signal e1, and display the sampled video signal f1 (for example, a liquid crystal panel). ) Is displayed.

The smear determination circuit 32 satisfies the above condition based on the vertical synchronizing signal e1 supplied when the predetermined condition is satisfied (in this embodiment, the video display switch of the master device 20 is turned on). In the following predetermined field (this field is the Nth field),
The control signal v1 for turning off the detection of the average brightness is supplied to the average brightness detection circuit 33, and the exposure control circuit 28
Is supplied with an exposure setting signal w1 indicating a predetermined exposure time A,
In the (N + 1) th field, the exposure time is half the A
The exposure control circuit 2 outputs the exposure setting signal w1 set to x (1/2)
Exposure setting signal w1 which is supplied to 8 and thereafter the exposure time is halved for each field up to the N + Kth field.
Is supplied to the exposure control circuit 28.

The exposure time T of the N + Pth field in this case can be expressed by the following equation.

T = A × (1/2) ^P (1) The smear determination circuit 32 horizontally changes the exposure time from the Nth field to the N + Kth field as shown in the equation (1). The luminance of each pixel of the composite video signal c1 for one screen is detected based on the synchronizing signal d1, the vertical synchronizing signal e1, and the sampling clock signal u1, and the proportion of the luminance when the exposure time is changed is equal to or less than a predetermined value. In this case, it is determined that smear occurs at the position of the pixel, the smear position is stored, and in the N + Kth field and thereafter, the average brightness detection circuit 33 turns on the average brightness detection control signal v1. Is supplied, the exposure setting signal w1 to the exposure control circuit 28 is supplied and stopped, and the smear determination signal x1 indicating the stored smear position is supplied to the average luminance detection circuit 33. When no smear is detected, the smear determination circuit 32 supplies the smear determination signal x1 indicating that there is no smear to the average luminance detection circuit 33 in the N + Kth and subsequent fields.

When the control signal v1 for turning on the average brightness detection is supplied, the average brightness detection circuit 33
Based on the supplied horizontal synchronization signal d1, vertical synchronization signal e1 and sampling clock signal u1, the period of the pixel where the smear is located, which is indicated by the smear determination signal x1, is removed from the composite video signal c1 for one screen, and the remaining period The average brightness is detected and a data signal g1 indicating this average brightness is output. When the smear determination signal x1 does not indicate the presence of smear when the control signal v1 for turning on the detection of the average brightness is supplied, the average brightness detection circuit 33 outputs the composite video signal c1 for one screen. The average brightness of is detected, and the data signal g1 indicating the detection result is output. Furthermore, when the control signal v1 for turning off the detection of the average brightness is supplied, the average brightness detection circuit 33 does not detect the average brightness and does not output the data signal g1.

The exposure control circuit 28 includes a smear determination circuit 32.
When the exposure setting signal w1 is supplied from, an exposure control signal for adjusting the exposure time indicated by the exposure setting signal w1 is created,
This exposure control signal is modulated at a predetermined frequency and guided to the wiring connection terminal 21 as a modulated exposure control signal h1.

Further, the exposure control circuit 28 underexposes the exposure when the average brightness indicated by the data signal g1 becomes higher than a predetermined level when the exposure setting signal w1 is not supplied from the smear determination circuit 32. If the average brightness indicated by the data signal g1 is adjusted to be lower than a predetermined level, an exposure control signal for adjusting the overexposure is created, the exposure control signal is modulated at a predetermined frequency, and the modulated exposure control signal is generated. It is led to the wiring connection terminal 21 as h1.

The power supply voltage output circuit 29 creates a DC power supply voltage Va from the commercial AC voltage and guides it to the wiring connection terminal 21.

The slave unit 40 will be described below.

The wiring connection terminal 42 is connected to the reference potential point connection terminal of each circuit.

The voice circuit 43 separates the voice signal output from the voice circuit 24 on the master unit 20 side from various signals guided from the wiring connection terminal 41 by the hybrid transformer, amplifies it, and outputs it to the handset 45 as the voice signal p1. A voice signal q, which will be described later, from the handset 45
1 is led to the wiring connection terminal 41.

The handset 45 is provided with a microphone and a speaker, outputs the audio signal p1 from the audio circuit 43 from the speaker, and guides the audio signal q1 received by the microphone to the audio circuit 43.

The input terminal of the power supply circuit 44 is the slave unit 40.
Connected to the wiring connection terminal 41 of the wiring connection terminal 4
The power supply voltage Va is separated from various signals led to 1, and the separated power supply voltage Va is converted into a power supply voltage Vb having a predetermined value by a switching regulator and is supplied to the CCD video camera unit 46.

The control signal demodulation circuit 50 includes a wiring connection terminal 4
The modulated exposure control signal h1 from 1 is demodulated, an exposure up signal r1 and an exposure down signal s1 are created from the demodulated exposure control signal, and are supplied to the CCD video camera unit 46.

The CCD video camera unit 46 uses a CCD (charge coupled device) as an image pickup device,
The photodiode of the light receiving portion corresponds to a pixel and is turned on by the supply of the power supply voltage Vb to perform image capturing, and the video signal t1 of the captured screen is supplied to the transmission circuit 47 and the control signal demodulation circuit 50 outputs the signal. Exposure up signal r
1 and the image signal t1 of the screen set to be exposed by the exposure down signal s1 are supplied to the transmission circuit 47.

The transmission circuit 47 modulates the video signal t1 from the CCD video camera unit 46 at a predetermined frequency,
Lead to the wiring connection terminal 41.

The smear determination circuit 32 will be described in more detail.

FIG. 2 is a block diagram showing the smear determination circuit 32 of FIG.

In FIG. 2, the horizontal synchronizing signal d1, the vertical synchronizing signal e1, the sampling clock signal u1 and the composite video signal c1 are introduced to the input terminals 61, 62, 63 and 64 of the smear determining circuit 32, respectively.

The horizontal synchronizing signal d1, the vertical synchronizing signal e1 and the sampling clock signal u1 respectively guided to the input terminals 61, 62 and 63 are supplied to both the field memory 66 and the smear position judging control circuit 68.

Composite video signal c1 guided to the input terminal 64
Is supplied to the non-inverting input terminal (+) of the comparator 65. The reference voltage Vref is led to the inverting input terminal (−) of the comparator 65. This Vref is set to a level slightly lower than the white level in the composite video signal c1. The comparator 65 compares the composite video signal c1 with the reference voltage Vref, and when the composite video signal c1 exceeds the reference voltage Vref, the high level (first level).
Therefore, the 1-bit comparison detection signal c11 which becomes a low level (second level) when the composite video signal c1 does not exceed the reference voltage Vref is supplied to the field memory 66 and the first input of the AND circuit 67 Supply to the terminal.

The field memory 66 is provided with a storage area for one field of the 1-bit comparison detection signal c11, and the supplied horizontal synchronization signal d1 and vertical synchronization signal e.
The data of the comparison detection signal c11 is stored for one field based on 1 and the sampling clock signal u1, and the data of the comparison detection signal c11 which is one field after the storage is read and read as the one field delay comparison detection signal c12. The data of the comparison detection signal c11 is stored in the read empty region while being supplied to the second input terminal of the. The AND circuit 67 outputs the comparison detection signal c
AND of 12 and 1-field delayed comparison detection signal c12 is taken and supplied as a comparison detection signal c13 to the smear position determination control circuit 68.

With such a configuration, the AND circuit 67.
Is a high level (first level) when the brightness of the composite video signal c1 exceeds a predetermined level in both the 1-field delayed comparison detection signal c12 from the field memory 66 and the comparison detection signal c11 from the comparator 65. And outputs a low level (second level) when the brightness of the composite video signal c1 does not exceed the predetermined level in at least one of the 1-field delayed comparison detection signal c12 and the comparison detection signal c11. It is a logic circuit that does.

The smear position determination control circuit 68 outputs the control signal v1 for turning off the detection of the average brightness in the Nth field based on the vertical synchronizing signal e1 supplied when a predetermined condition is satisfied. In addition to 70, the exposure setting signal w1 indicating the predetermined exposure time A is guided to the output terminal 71, and in the N + 1th field, the exposure setting signal w1 whose exposure time is halved is guided to the output terminal 71. The exposure setting signal w1 whose exposure time is halved for each field is led to the output terminal 71 up to the field. The smear position determination control circuit 68 changes the exposure time from the Nth field to the N + Kth field, and based on the horizontal synchronization signal d1, the vertical synchronization signal e1 and the sampling clock signal u1, the comparison detection signal c13.
Is detected and the comparison detection signal c13 for one field is changed, that is, after the high-level period of the comparison detection signal c13 for one field is decreased, M
The pixel position where the comparison detection signal c13 becomes high level after the field is determined to be the smear position, the data c14 of this smear position is stored in the memory 69, and the average luminance is output to the output terminal 70 in the N + Kth field and thereafter. The control signal v1 for turning on the detection is supplied, the guiding of the exposure setting signal w1 to the output terminal 71 is stopped, and the smear determination signal x1 indicating the smear position data c14 stored in the memory 69 is output terminal 72. Lead to. In addition, the smear position determination control circuit 68 outputs M after the period of high level in the comparison detection signal c13 for one field decreases.
When the comparison detection signals c13 for one field are all at a low level after the field, it is determined that smear is not detected, and in the N + Kth and subsequent fields,
A smear determination signal x1 indicating that there is no smear is led to the output terminal 72.

The control signal v1 and the smear determination signal x1 introduced to the output terminals 70 and 72, respectively, are supplied to the average luminance detection circuit 33 of FIG. The exposure setting signal w1 to the output terminal 71 is supplied to the exposure control circuit 28.

The operation of such an embodiment will be described below.

First, the operation when the smear of the screen imaged by the CCD video camera unit 46 occurs will be described. In this case, the video display switch of the master device 20 is turned on. As a result, the smear position determination control circuit 68 of the smear determination circuit 32 guides the control signal v1 for turning off the average brightness detection to the average brightness detection circuit 33 in the Nth field, and indicates the predetermined exposure time A. The exposure setting signal w1 is guided to the exposure control circuit 28. This allows
The exposure control circuit 28 creates an exposure control signal adjusted to the exposure time A, modulates this exposure control signal at a predetermined frequency, and guides it as a modulated exposure control signal h1 to the control signal demodulation circuit 50 via the wiring 11. The control signal demodulation circuit 50 demodulates the modulated exposure control signal h1 from the wiring connection terminal 41 to create an exposure up signal r1 and an exposure down signal s1 for adjusting the exposure time A to generate the CCD video camera unit 4.
It is designed to supply to 6. As a result, the CCD video camera unit 46 sets the exposure time of the electronic shutter to the exposure time A and supplies the video signal t1 to the transmission circuit 47. Next, the exposure control circuit 28 guides the exposure setting signal w1 for which the exposure time is halved to A × (1/2) to the exposure control circuit 28 in the (N + 1) th field.
The exposure control circuit 28 is supplied with the exposure setting signal w1 that halves the exposure time for each field up to the + Kth field. As a result, the CCD video camera unit 46
The exposure time of the electronic shutter is reduced by half for each field. The smear position determination control circuit 68 operates from the Nth to Nth
The comparison detection signal c13 is detected with the exposure time changed to the + Kth field. Where CCD
When the composite video signal c1 is equal to or lower than the reference voltage Vref on a part of the screen imaged by the video camera unit 46, that is, when a pattern is formed on the part of the screen by the imaged image, the position of the screen where the pattern is generated appears. The comparison detection signal c11 of the corresponding comparator 65 becomes low level, and the AND circuit 67
Output becomes low level, and smear position determination control circuit 6
Reference numeral 8 determines the position of a pixel at which the comparison detection signal c13 becomes high level M fields after the output of the AND circuit 67 becomes low level as a smear position, and stores the smear position data c14 in the memory 69. To do. After that, the smear position determination control circuit 68 supplies the control signal v1 for turning on the average luminance detection to the output terminal 70 to the average luminance detection circuit 33 and the exposure control circuit 28 in the N + Kth field and thereafter. The leading of the exposure setting signal w1 is stopped, and the smear determination signal x1 indicating the data of the smear position stored in the memory 69 is used as the average luminance detection circuit 33.
Supply to. As a result, the average luminance detection circuit 33 is set to 1
The period of the pixel where the smear is located, which is indicated by the smear determination signal x1, is removed from the composite video signal c1 for the screen, the average luminance of the remaining period is detected, and the data signal g indicating this average luminance is detected.
1 is output.

In such a state, when the average brightness of the remaining period of the data signal g1 is overexposed, the exposure control circuit 28 indicates that the average brightness of the data signal g1 is higher than a predetermined level. Therefore, an exposure control signal for adjusting the exposure to under is created and is guided to the control signal demodulation circuit 50 via the wiring 11 as the modulated exposure control signal h1. As a result, the CCD video camera unit 46 reduces the exposure time to shorten the exposure time of the electronic shutter and supplies the video signal t1 to the transmission circuit 47. The transmission circuit 47 is a CC
The video signal t1 from the D video camera unit 46 is modulated at a predetermined frequency and guided to the signal separation / demodulation circuit 25 via the wiring 11.

When the average luminance of the remaining period of the data signal g1 is underexposed, the exposure control circuit 28 indicates that the average luminance of the data signal g1 has become lower than the predetermined level, and therefore the exposure control circuit 28 is exposed. Generates an exposure control signal for adjusting the exposure to over, and guides it as a modulated exposure control signal h1 to the control signal demodulation circuit 50 via the wiring 11. C
The CD video camera unit 46 increases the exposure to increase the exposure time of the electronic shutter and supplies the video signal t1 to the transmission circuit 47.

By repeating such an operation, the brightness of the portion of the screen displayed on the monitor unit 27 excluding the smear can be set to the brightness of the proper exposure.

The operation when the smear of the screen imaged by the CCD video camera unit 46 does not occur will be described below. Also in this case, the video display switch of the master device 20 is turned on. As a result, the smear position determination control circuit 6
8 detects the comparison detection signal c13 while changing the exposure time from the Nth field to the N + Kth field. Here, in a state where the composite video signal c1 is below the reference voltage Vref in a part of the screen imaged by the CCD video camera unit 46, the output of the AND circuit 67 becomes low level, and the smear position determination control circuit 68 causes the AND circuit 67 to operate. 1 after M fields after the output of becomes low level
The field comparison detection signals c13 are all at a low level. Therefore, the smear position determination control circuit 68 is N +
In the Kth field and thereafter, the average luminance detection circuit 3
The control signal v1 for turning on the detection of the average luminance is supplied to the output terminal 70 of No. 3 and the exposure control circuit 28 is stopped from leading the exposure setting signal w1 to generate the smear determination signal x1 indicating no smear. The average luminance detection circuit 33 is supplied. The average luminance detection circuit 33 detects the average luminance of the composite video signal c1 for one screen and outputs the data signal g1 indicating the detection result.

The exposure control circuit 28 creates an exposure control signal for adjusting the exposure to over when the average luminance indicated by the data signal g1 is underexposed, and when the average luminance indicated by the data signal g1 is overexposed. Creates an exposure control signal for adjusting the exposure to under, and the control signal demodulation circuit 5
Lead to 0.

By repeating the above operation, C
The brightness of the entire screen displayed on the CD video camera unit 46 can be set to the brightness of proper exposure.

As described above, in the present embodiment, the smear determination circuit 32 detects the position where smear occurs in the composite video signal c1, and the average luminance detection circuit 33 detects the composite video signal c1 for one screen. The period which becomes the position of the smear is removed, the average luminance of the remaining period is detected, and the data signal g1 of this detection result is supplied to the exposure control circuit 28, and the exposure control circuit 28 based on such data signal g1. Since exposure control is performed, appropriate exposure can be obtained even when smear occurs, and a high impression can be given to the user.

In the embodiment shown in FIG. 1, since the exposure time is changed during the period from the Nth field to the N + Kth field, the exposure time is halved for each field, but the exposure time is changed. For example, another method may be used such that the exposure time is set to 1/3 for each frame. Further, in the embodiment shown in FIG. 1, the smear determination circuit 32 and the average luminance detection circuit 33 are configured to detect the composite video signal c1 from the signal separation / demodulation circuit 25, but instead of the composite video signal c1. Alternatively, the video signal f1 from the sync signal separation / video signal processing circuit 26 may be detected.
Further, in the embodiment shown in FIG. 1, the exposure control circuit 28,
The smear determination circuit 32 and the average luminance detection circuit 33 are connected to the base unit 2
However, it may be provided in the child device 40. Further, in the embodiment shown in FIG. 1, the shutter control signal device of the present invention is applied to a TV doorphone in which smear is likely to occur, but is applied to other devices such as an indoor TV intercom device. May be. Furthermore, in the embodiment of FIG.
The composite video signal c1 is led to the non-inverting input terminal (+) of the comparator 65, and the inverting input terminal (-) of the comparator 65 is led.
The reference voltage Vref to the AND circuit 6 as an arithmetic circuit.
7 is used, the reference voltage Vref is guided to the non-inverting input terminal (+) of the comparator 65, the composite video signal c1 is guided to the inverting input terminal (−) of the comparator 65, and a NOR circuit is used for the arithmetic circuit. May be.

[0059]

As described above, according to the present invention, the position where the smear of the video signal from the video camera unit is generated can be determined, and the proper exposure can be obtained even when the smear is generated. It can give a high impression to the user.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a smear determination system, a shutter control device, and a TV door phone using the control device according to the present invention.

FIG. 2 is a block diagram showing the smear determination circuit of FIG.

[Explanation of symbols]

 10 TV Doorphone 11, 12 Wiring 20 Base Unit 28 Exposure Control Circuit 31 Sampling Clock Generation Circuit 32 Smear Judgment Circuit 33 Average Brightness Detection Circuit 40 Handset 46 CCD Video Camera Unit

[Procedure amendment]

[Submission date] September 14, 1994

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Correction target item name] All drawings

[Correction method] Change

[Correction content]

FIG.

[Fig. 2]

Front page continuation (72) Inventor Akio Yamagishi 25-1 Ekimaehonmachi, Kawasaki-ku, Kawasaki-shi, Kanagawa Toshiba Microelectronics Corporation

Claims (8)

[Claims] 1. A video camera unit for picking up an image using a liquid crystal panel charge coupled device and outputting a video signal, an exposure control circuit for controlling the exposure of an electronic shutter of the video camera unit, and when a predetermined condition is satisfied. , The brightness of the video signal from the video camera unit is detected in a state where the exposure control circuit is controlled to gradually reduce the exposure time during a predetermined period, and the rate of change in the brightness during the predetermined period is a predetermined value. A smear determination system comprising: a smear determination circuit that determines the following positions of a video signal as positions where smear has occurred. 2. A video camera unit for imaging using a charge-coupled device and outputting a video signal, an exposure control circuit for controlling exposure of an electronic shutter of the video camera unit, and a predetermined condition when a predetermined condition is satisfied. The brightness of the video signal from the video camera unit is detected in a state in which the exposure control circuit is controlled to reduce the exposure time stepwise during the period, and the rate of change in the brightness is below a predetermined value during the predetermined period. The smear determination circuit that determines the position of the image signal that has become smear as the position where smear has occurred, removes the video signal at the position of the smear determined by the smear determination circuit from the video signal from the video camera unit, and removes the remaining video signal. Exposure control of the electronic shutter of the video camera unit by detecting the average brightness and controlling the exposure control circuit based on the detection result A shutter control device comprising: an average luminance detection circuit for performing the above. 3. An exposure control circuit, a smear determination circuit, and an average luminance detection circuit are provided on at least one of the first and second devices, the first and second devices being connected to each other by wiring. Then, the video unit is mounted on the second device, and a monitor for displaying a video signal supplied from the video unit through the wiring is provided on the first device. 2. The shutter control device described in 2. 4. The shutter control device according to claim 3, and an audio circuit for transmitting and receiving an audio signal between the first device and the second device via the wiring. And TV intercom. 5. A video camera unit for imaging using a charge coupled device and outputting a video signal, an exposure control circuit for controlling exposure of an electronic shutter of the video camera unit, and a video signal for the video signal from the video camera unit. A comparator that compares the brightness with a predetermined level and outputs a comparison detection signal indicating whether or not the brightness of the video signal exceeds the predetermined level; and a comparison detection signal from the comparator, which is stored for one field. A field memory for outputting a 1-field delayed comparison detection signal by reading out a comparison-detection signal after 1 field has been stored, and a 1-field delay comparison detection signal from this field memory and a comparison detection signal from the comparator. In both cases, when the brightness indicates that the brightness exceeds a predetermined level, Carried force, second when the luminance at least one of the comparison detection signal from the 1-field delay comparison detection signal and said comparator from said field memory showed that it did not exceed a predetermined level
When a predetermined condition is satisfied, the exposure control circuit is controlled for a predetermined period to reduce the exposure time for each field, and the output from the logic circuit is detected. The image from the video camera unit corresponding to the position where the output from the logic circuit becomes the second level after a predetermined field from the change in the output from the logic circuit for one field during the predetermined period A smear determination system comprising: a smear position determination control circuit for determining the position of a signal as a position where smear has occurred. 6. A video camera unit for picking up an image using a charge-coupled device and outputting a video signal, an exposure control circuit for controlling the exposure of an electronic shutter of the video camera unit, and a video signal from the video camera unit. A comparator that compares the brightness with a predetermined level and outputs a comparison detection signal indicating whether or not the brightness of the video signal exceeds the predetermined level; and a comparison detection signal from the comparator, which is stored for one field. A field memory for outputting a 1-field delayed comparison detection signal by reading out a comparison-detection signal after 1 field has been stored, and a 1-field delay comparison detection signal from this field memory and a comparison detection signal from the comparator. In both cases, when the brightness indicates that the brightness exceeds a predetermined level, Carried force, second when the luminance at least one of the comparison detection signal from the 1-field delay comparison detection signal and said comparator from said field memory showed that it did not exceed a predetermined level
When a predetermined condition is satisfied, the exposure control circuit is controlled for a predetermined period to reduce the exposure time for each field, and the output from the logic circuit is detected. The image from the video camera unit corresponding to the position where the output from the logic circuit becomes the second level after a predetermined field from the change in the output from the logic circuit for one field during the predetermined period A smear position determination control circuit that determines the position of the signal as a position where smear has occurred, and a video signal at the smear position determined by the smear position determination control circuit from the video signal from the video camera unit is removed, and the remaining video signal The average brightness of the video camera unit is detected, and the exposure control circuit is controlled based on the detection result to control the exposure of the electronic shutter of the video camera unit. Controller of the shutter, characterized by comprising the average luminance detection circuit that performs. 7. An exposure control circuit, a comparator, a field memory, a logic circuit, and a smear position determination control are provided in at least one of the first and second devices, the first and second devices being connected to each other by wiring. A circuit and an average luminance detection circuit are mounted, the video unit is mounted on the second device, and a monitor for displaying a video signal supplied from the video unit via the wiring is displayed on the first device. 7. The shutter control device according to claim 6, wherein the shutter control device is provided. 8. The shutter control device according to claim 7, and an audio circuit for transmitting and receiving an audio signal between the first device and the second device via the wiring. And TV intercom.