JPH0458230B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color lamella device, and more particularly to an automatic aperture device thereof. Conventional devices of this kind have an electric aperture device, which detects an error signal from the imaging output, and can control the aperture of the electric aperture device to an appropriate aperture state based on this error signal, and can also remove this control. This allows you to change the aperture by turning the aperture ring by hand.

By the way, when changing the aperture manually, if you want to control the automatic white level balance adjustment circuit, it is necessary to manually adjust the aperture in advance, otherwise white level balance adjustment will not be possible. becomes.

In other words, when adjusting the white level balance, if the aperture is opened too much, excessive imaging output will be obtained, which may cause the clip circuit or knee circuit to operate, making it impossible to achieve accurate white level balance. be. On the other hand, if the aperture is too closed, the level of the imaging output will be too low, resulting in the drawback that accurate white level balance cannot be achieved. It can be said that white level balance is most efficient when the level of the imaging output is appropriate.

In view of this, the present invention provides that even when changing the aperture manually, when operating the automatic white level balance adjustment circuit, the automatic aperture control circuit operates normally and ensures that the white level balance (white It is an object of the present invention to provide a color camera device in which balance adjustment is performed.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings. Reference numeral 1 denotes an electric aperture device, which is composed of an aperture 5 provided in a lens system 4 and a motor 6 for driving the aperture 5.
Reference numeral 8 denotes a camera head circuit, which obtains red, green, and blue imaging signals R, G, and B from, for example, a three-color image pickup tube, and supplies these signals to a signal processing circuit 9.
A luminance signal Y and color difference signals R-Y and B-Y are obtained from the signal processing circuit 9 and supplied to an encoder 10 of a desired system, for example, an NTSC system. Note that 11 is an output terminal from which a composite color video signal of the NTSC system is obtained.

The signal processing circuit 9 is provided with an automatic black level balance adjustment circuit 3 and an automatic white level balance adjustment circuit 7 below circuits such as a matrix circuit and a γ correction circuit. SW ₂ is a switch (second switch) for operating these adjustment circuits 3 and 7,
It has a movable contact t, a fixed contact w for white level balance adjustment command, and a fixed contact b for black level balance adjustment command. The movable contact t is connected to the power supply +B ₃ (the power supply voltage is V ₃ ), and the adjusting circuits 3 and 7 can be selectively put into operation by switching the movable contact t. Note that n is a neutral contact when neither of the adjustment circuits 3 and 7 is operated.

Reference numeral 2 denotes an automatic aperture control circuit that controls the aperture 5 of the electric aperture device 1 described above to an appropriate aperture state. This includes an error signal generation circuit 12 that generates an error signal as a comparison output by comparing an imaging output, for example, a luminance signal Y, with a reference voltage, and generates a voltage according to the error signal and the aperture state of the aperture 5. It is comprised of an arithmetic circuit (comparison circuit) 13 that controls the motor 6 by comparing aperture state detection signals from a potentiometer 14 as a voltage generating circuit. The potentiometer 14 is connected to the power supply (the power supply voltage is
V ₄ ) + B ₄ and ground.

During automatic aperture control, one end of the motor 6 is configured to receive a reference voltage of V ₁ /2 from the power supply +B ₂ , and a voltage of 0 to V ₁ is applied to the other end of the motor 6 from the arithmetic circuit 13. It is made so that it can be done.
That is, since the variation range of the voltage applied from the output side of the arithmetic circuit 13 to the other end of the motor 6 is 0 to V ₁ , by applying the center potential V ₁ /2 to one end of the motor 6 as a reference voltage. , the operating range is maximized. The reference voltage V ₁ /2 applied to one end of the motor 6 is applied via a switch (first switch) SW ₁ . This switch _SW1 has a movable contact r connected to one end of the motor 6, a fixed contact a for automatic aperture control connected to the power supply + _B2 , and a fixed contact m for manual aperture adjustment.

SW ₃ is a third switch that operates in conjunction with the second switch SW ₂ , and this third switch SW ₃ also controls the shutoff operation of the automatic aperture control circuit 2 by the first switch SW ₁ . Regardless, the automatic aperture control circuit 2 is forced to operate. Third switch SW ₃
has the same configuration as the second switch SW ₂ , in which the fixed contacts w and b are both connected to the power supply +B ₂ whose power supply voltage is V ₁ /2, and the movable contact t is connected to the first switch SW 2.
Connected to fixed contact m of SW ₁ . Further, the fixed contact b of the second switch SW ₂ is particularly connected to the error signal generating circuit 12 as well.

Next, let us explain the operation of this device. When the electric aperture device 1 is controlled by the automatic aperture control circuit 2 to automatically change the aperture 5, the first switch
The movable contact r of SW ₁ is switched to the fixed contact a side,
A reference voltage of V ₁ /2 is applied to one end of the motor 6 . Then, the rotation of the motor 6 is controlled based on the error signal detected from the luminance signal Y as the imaging output. For example, when the motor 6 rotates forward, the aperture 5
The aperture becomes small and becomes large when rotated in the opposite direction. Further, when a voltage smaller than V ₁ /2 is applied to the other end of the motor 6, the aperture of the diaphragm 5 becomes large, and when a voltage larger than V ₁ /2 is applied, the aperture becomes small. . Also, when aperture 5 is fully open, potentiometer 1
It is assumed that a voltage of V4 to 0 is generated, and when the gate is completely closed, a voltage of _V4 is generated and supplied to the arithmetic circuit 13, respectively. The arithmetic circuit 13 receives a luminance signal Y.
An error signal of a voltage of V ₄ to 0 is supplied depending on the magnitude of the voltage, and when the level of the brightness signal Y is higher than the reference level, the voltage applied to the other end of the motor 6 is set to be higher than V ₁ /2. , when the level of the luminance signal Y is lower than the reference level, the voltage applied to the other end of the motor 6 is made smaller than V ₁ /2. Therefore, the arithmetic circuit 13 compares the levels of the error signal from the error signal generating circuit 12 and the detection signal from the potentiometer 14, and rotates the motor 6 in the forward or reverse direction until they match. When the voltage at the other end reaches V ₁ /2, the motor 6 stops its rotation.

Next, when adjusting the aperture 5 manually, the movable contact r of the first switch _SW1 is switched to the fixed contact m. At this time, if the movable contacts t of the second and third switches SW ₂ and SW ₃ are switched to the neutral fixed contact n, automatic aperture control is not performed and the aperture 5 is rotated by the aperture ring (not shown). It can be changed manually depending on the movement.
Also, when the movable contacts t of the second and third switches SW ₂ and SW ₃ are switched to the fixed contacts w or b, the voltage V ₁ /2 from the power supply +B ₂ is applied to the third and first switches SW ₃ and SW ₁ to one end of the motor 6, automatic aperture control is performed in the same manner as described above, and the automatic white level balance adjustment circuit 7 or the automatic black level balance adjustment circuit 3 is brought into operation. In this case, the automatic aperture control circuit 2 operates normally when adjusting the white level balance, but when adjusting the black level balance, the voltage V ₃ from the power supply +B ₃
is supplied to the error signal generation circuit ₁₂ via the second switch SW2, and is fixed at the error signal voltage _V4 , the motor 6 rotates forward and the diaphragm 5 is completely closed. In this way, automatic black level balance adjustment is ensured. Note that the magnitudes of the voltages V ₁ , V ₃ , and V ₄ described above have no particular interdependence, and can be arbitrarily set so that each circuit can operate efficiently.

According to the present invention described above, even when the aperture is manually operated, when operating the white level balance adjustment circuit, the automatic aperture control circuit is operated to prevent the aperture from opening or closing too much to adjust the white level. Since the balance is adjusted, a special effect is obtained when the white level balance is accurately matched.

Furthermore, according to the present invention, there is no need to manually set the aperture to an appropriate value, which not only simplifies the operation, but also prevents the user from taking a picture without being able to accurately adjust the white level balance. . Therefore, there is a special effect that there is no possibility that the white level balance of the photographed image is not correct after photographing.

[Brief explanation of the drawing]

The figure is a block diagram showing one embodiment of the present invention. 1 is an electric diaphragm device, 2 is an automatic diaphragm control circuit, 3
4 is an automatic black level balance adjustment circuit, 4 is a lens system, 5 is an aperture, 6 is a motor, 7 is an automatic white level balance adjustment circuit, 9 is a signal processing circuit, 12 is an error signal generation circuit, 13 is an arithmetic circuit, and 14 is a Potentiometers SW ₁ to SW ₃ are first to third switches.

Claims (1)

[Claims] 1. A diaphragm mechanism that controls the amount of incident light, a drive motor that drives the diaphragm mechanism, the level of the imaging output and a reference voltage are compared, an error signal is obtained as the comparison output, and the error signal is an automatic aperture control circuit that controls the drive motor so that the aperture of the aperture mechanism is in an appropriate aperture state based on the aperture, and an automatic white level balance adjustment that automatically adjusts the white balance in response to a video signal. and a changeover switch that selectively switches the operating state of the automatic iris control circuit to an automatic control mode in which the drive motor is controlled based on the error signal or a manual control mode in which the iris mechanism is manually operated. and a control means for controlling the changeover switch so that the automatic aperture control circuit switches to the automatic control mode when the automatic white level balance adjustment circuit is switched to the operating state, A color camera device characterized in that the video signal of a predetermined level is obtained so that accurate white level balance adjustment can be performed during automatic white level balance adjustment.