KR100238226B1 - Apparatus for controlling video camera iris by using pre-blanking and window mixed circuit - Google Patents

Abstract

Disclosed is a video camera aperture control apparatus using a pre-blanking and window mixing circuit according to the present invention.

The configuration of the apparatus includes an aperture for adjusting the amount of light incident by a predetermined control signal; A CCD device for converting an optical signal passing through the aperture and the video camera lens into an electrical signal; A CDS for selecting and sampling only main data from which noise included in an electrical signal output from the CCD device is removed; A differential amplifier amplifying the sampled main data; A clamp circuit for constantly holding an optical black level of the amplified main data; Pre-switching the clamped main data, arbitrarily setting and switching the main data transmission period, outputting the main data in the main data transmission period, and outputting a reference voltage in the period during which the main data is not transmitted. Blanking and window mixing circuits; A buffer which temporarily stores and outputs the main data output from the pre-blanking and window mixing circuit; And an aperture control unit configured to remove the high frequency component of the main data output from the buffer and compare the same with a predetermined reference voltage to control the aperture. According to the present invention, the pre-blanking and window functions can be processed in parallel at the same time inside the IC to realize the function simplification and the hardware simplified.

Description

Apparatus for controlling video camera iris by using pre-blanking and window mixed circuit}

The present invention relates to a video camera iris control apparatus, and more particularly, pre-blanking and window functions are simultaneously processed in parallel within an IC to simplify functions and simplify hardware. A video camera aperture control device using a pre-blanking and window mixing circuit.

1 is a view showing the configuration of a conventional video camera aperture control device.

In Fig. 1, reference numeral 10 denotes an iris, 12 denotes a lens, 14 denotes a CCD element (solid-state image sensor), 16 denotes an analog signal processor, 160 denotes a correlated double sampling (CDS), and 162 denotes a differential amplifier. 164 denotes a clamp circuit, 166 denotes a pre-blanking circuit, 168 denotes a buffer, 18 denotes an aperture control, 180 denotes an aperture controller, 182 denotes a comparator, 184 denotes a low pass filter, and 186 denotes a window circuit. .

In FIG. 1, the analog signal processor is configured as an IC, and the aperture controller is configured as an external application.

Referring to the operation of the device shown in Figure 1 as follows.

The aperture 10 adjusts the amount of light incident by a predetermined control signal. The CCD element 14 converts the optical signal passing through the aperture 10 and the lens 12 into an electrical signal. The analog signal processor 16 removes and amplifies the noise included in the input electrical signal, clamps the black level, and removes the noise included in a period other than the main data transmission period (horizontal retrace period). The aperture control unit 18 controls the aperture 10 by removing a high frequency component of the main data output from the analog signal processor 160, comparing the reference signal with a reference level, and then outputting an aperture control signal.

The CDS 160 selects and samples only main data from which the noise included in the electrical signal output from the CCD element 14 is removed. The differential amplifier 162 amplifies the sampled main data. The clamp circuit 164 inputs the amplified main data to keep the optical balck level constant. The pre-blanking circuit 166 outputs a reference voltage in a period other than the period in which the main data is transmitted. The buffer 168 temporarily stores the main data.

The window circuit 186 arbitrarily sets and switches the main data transfer period. In more detail, a part of the entire screen is composed of a window (meaning to open a window) so that the main data passes only during a period in which the window pulse is high, ultimately controlling the aperture to input the light into the CCD element 14. Control the signal amount.

The low pass filter 184 removes the signal of the high frequency band to extract the luminance average level included in the main data output from the window circuit 186. The comparator 182 compares the predetermined reference voltage with the main data passing through the low pass filter 184 and outputs a comparison signal corresponding to the difference between the predetermined reference voltage and the main data. The aperture controller 180 inputs a comparison signal and outputs an aperture control signal for controlling the aperture 10.

FIG. 2 is a diagram showing a detailed configuration of the pre-blanking circuit (same as the window circuit) shown in FIG. 1.

In Fig. 2, reference numerals 1660 to 1664 denote first to third comparators, and 1666 denote current source stages, respectively.

The operation of the pre-blanking circuit 166 shown in FIG. 2 will be described in more detail as follows.

The pre-blanking circuit 166 inputs a pre-blanking pulse from a timing generator IC to output a reference voltage when the pulse is low (8-12 μs), and mains during the high-in period (55.5-51.5 μs). Outputting the data ultimately eliminates the noise contained in the main data by setting the period without main data to a new level.

Accordingly, the first comparator 1660 composed of the transistors Q1 / Q2, the second comparator 1662 composed of the transistors Q12 / Q13, and the third comparator 1664 composed of the transistors Q104 / Q105 perform a switching operation. The current source stage 1666 supplies a bias voltage to the entire block. The voltage indicated at each node is determined by the DC voltage based on the current determined by the current source stage 1666. Here, the circuit is constructed assuming that the base-emitter voltage of the transistors is uniformly Vbe = 0.75V regardless of the collector current of each transistor.

The window circuit 186 constitutes a specific part of the entire screen as a window (meaning to open a window) so that the main data passes only during a period in which the window pulse is high, and ultimately controls the aperture to input the CCD element 14. It is a circuit for controlling the amount of optical signal.

In the conventional video camera aperture control device, since the pre-blanking circuit is implemented in the IC and the window circuit is implemented in the external application, the device is complicated and expensive.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is a video using a pre-blanking and window mixing circuit which realizes simplicity and hardware simplification by simultaneously processing the pre-blanking and windowing functions in parallel in the IC. It is an object of the present invention to provide a camera aperture control device.

1 is a view showing the configuration of a conventional video camera aperture control device.

FIG. 2 is a diagram showing a detailed configuration of the pre-blanking circuit (same as the window circuit) shown in FIG. 1.

3 is a view showing the configuration of a video camera aperture control apparatus using a pre-blanking and window mixing circuit according to the present invention.

FIG. 4 is a diagram illustrating a detailed configuration of the pre-blanking and window mixing circuit shown in FIG. 3.

5 is a timing diagram for explaining the operation of the pre-blanking and window mixing circuit according to the present invention.

In order to achieve the above object,

An apparatus for controlling a video camera aperture, comprising: an aperture for adjusting an amount of light incident by a predetermined control signal; A CCD device for converting an optical signal passing through the aperture and the video camera lens into an electrical signal; Correlated Double Sampling (CDS) for selecting and sampling only main data from which noise is included in an electrical signal output from the CCD device; A differential amplifier amplifying main data sampled at the CDS; A clamp circuit that constantly holds the optical black level of the main data amplified by the differential amplifier; The main data output from the clamp circuit is input, the main data transmission period is arbitrarily set and switched, the main data is output during the main data transmission period, and a reference voltage is output during the period when the main data is not transmitted. Pre-blanking and window mixing circuitry; A buffer which temporarily stores and outputs the main data output from the pre-blanking and window mixing circuit; An aperture control unit for removing a high frequency component of the main data output from the buffer, comparing the signal with a predetermined reference voltage, and outputting a control signal for controlling the aperture to the aperture; and including a window function and a pre-blanking function in the IC. There is provided a video camera aperture control apparatus using a pre-blanking and window mixing circuit, characterized in that simultaneously processing in parallel.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

3 is a view showing the configuration of a video camera aperture control apparatus using a pre-blanking and window mixing circuit according to the present invention.

The configuration of the apparatus shown in FIG. 3 includes a CCD element for converting an optical signal passing through an aperture 10, an aperture 10, and a lens 12 into an electrical signal to adjust an amount of light incident by a predetermined control signal ( 14; solid-state imaging device), the analog signal processing unit 16, the analog signal processing unit for removing the noise contained in the input electrical signal, amplifying and clamping at the black level and then removing the noise contained in the period other than the main data transmission period The aperture control unit 18 removes the high frequency component of the main data outputted from (16), compares it with a predetermined reference voltage, and outputs an aperture control signal for controlling the aperture.

Here, the analog signal processing unit 16 selects and samples only the main data from which the noise included in the electrical signal output from the CCD element 14 is removed, and a differential amplifier for amplifying the sampled main data. 162, a clamp circuit 164 for inputting amplified main data to constantly hold an optical balck level, and a pre-blanking circuit for outputting a reference voltage in a period other than a period during which main data is transmitted. A pre-blanking and window mixing circuit 167 which simultaneously performs the function of 166 and the window circuit for switching by arbitrarily setting the main data transfer period and the buffer 168 for temporarily storing the main data.

In addition, the aperture control unit 18 may include a low pass filter 184 for removing a signal of a high frequency band to extract a luminance average level included in main data output from the pre-blanking and window mixing circuit 167, and a predetermined reference voltage. The comparator 182 outputs a comparison signal for controlling the aperture 10 by comparing the main data passing through the low pass filter 184, and enters a comparison signal for controlling the aperture 10 and enters the aperture 10. The aperture controller 180 controls the amount of light to be used.

Next, the operation of the apparatus shown in FIG. 3 will be described.

The aperture 10 adjusts the amount of light incident by a predetermined control signal. The CCD element 14 converts the optical signal passing through the aperture 10 and the lens 12 into an electrical signal. The analog signal processor 16 removes and amplifies the noise included in the input electrical signal, clamps the black level, and removes the noise included in a period other than the main data transmission period (horizontal retrace period). The aperture control unit 18 controls the aperture 10 by removing the high frequency component of the main data output from the analog signal processor 160, comparing the predetermined high frequency component, and outputting an aperture control signal.

The CDS 160 selects and samples only main data from which the noise included in the electrical signal output from the CCD element 14 is removed. The differential amplifier 162 amplifies the sampled main data. The clamp circuit 164 inputs the amplified main data to keep the optical balck level constant. The pre-blanking and window mixing circuit 167 simultaneously performs the function of the pre-blanking circuit 166 for outputting the reference voltage and the function of the window circuit for arbitrarily setting and switching the main data transmission period in periods other than the main data transmission period. Perform. The buffer 168 temporarily stores the main data.

The low pass filter 184 removes the signal of the high frequency band to extract the luminance average level included in the main data output from the window circuit 186. The comparator 182 compares a predetermined reference voltage with main data passing through the low pass filter 184 to output a comparison signal for controlling the aperture 10. The aperture controller 180 inputs a comparison signal for controlling the aperture 10 to control the amount of light incident on the aperture 10.

FIG. 4 is a diagram illustrating a detailed configuration of the pre-blanking and window mixing circuit shown in FIG. 3.

In Fig. 4, reference numeral 1668 denotes a fourth comparator.

Since the configuration of the pre-blanking circuit 166 and the configuration of the window circuit 186 are the same, it is also possible to simply configure the pre-blanking and window mixing circuits by combining the two circuits. The advantages are relatively low. Accordingly, the window circuit 186 included in the external application is integrated with the pre-blanking circuit 166 inside the IC so that the two circuits are implemented as one. In FIG. 4, the fourth comparator 1668 is configured by connecting the transistor Q3 in parallel to the transistor Q4 having the collector terminal connected to the second comparator 1662, so that the entire circuit shown in FIG. 4 is a pre-blanking circuit and a window circuit. The function was performed at the same time.

Referring to the operation of the circuit shown in Figure 4 in more detail as follows.

The pre-blanking pulse is always in the on state, but the window pulse may alternately turn on and off by switching. In other words, in order to prevent the fourth comparator 1668 from malfunctioning and to allow the second comparator 1662 to operate, it is necessary to set the input bias voltage to 3V when the window function is turned off (where Q3 is off). . Comparing FIGS. 2 and 4, it can be seen that main data output from the pre-blanking and window mixing circuit 167 and main data output from the pre-blanking circuit are the same when the window pulse is off. In FIG. 4, when the window pulse is on, the main data signal is output only while the window pulse is high. Referring to the timing diagram of FIG. 5, it can be seen that a pre-blanking pulse period is included in the window pulse period, so that the window function operation takes precedence over the pre-blanking operation. That is, main data should be output when the pre-blanking pulse period is not low (8-12 μs period), but main data is not output while the window pulse is low (25-35 μs) while the pre-blanking pulse is high. The reference level is output.

As described above, according to the present invention, the pre-blanking and window functions are processed in parallel at the same time in the IC, thereby achieving the effect of simplifying the function and simplifying the hardware.

Claims (5)

In the video camera aperture control device, An aperture adjusting an amount of light incident by a predetermined control signal; A CCD device for converting an optical signal passing through the aperture and the video camera lens into an electrical signal; Correlated Double Sampling (CDS) for selecting and sampling only main data from which noise is included in an electrical signal output from the CCD device; A differential amplifier amplifying main data sampled at the CDS; A clamp circuit that constantly holds the optical black level of the main data amplified by the differential amplifier; The main data output from the clamp circuit is input, the main data transmission period is arbitrarily set and switched, the main data is output during the main data transmission period, and a reference voltage is output during the period when the main data is not transmitted. Pre-blanking and window mixing circuitry; A buffer which temporarily stores and outputs the main data output from the pre-blanking and window mixing circuit; And an aperture control unit which removes a high frequency component of the main data output from the buffer and compares it with a predetermined reference voltage and outputs a control signal for controlling the aperture to the aperture. An apparatus for controlling video camera aperture using a pre-blanking and window mixing circuit, wherein a window function and a pre-blanking function are simultaneously processed in parallel in an IC. The method of claim 1, wherein the pre-blanking and window mixing circuit is Pre-blanking and window mixing, characterized in that two transistors are arranged in pairs in order to sequentially output the main data and the reference voltage by switching by a window pulse and a pre-blanking pulse. Video camera aperture control device using a circuit. The method of claim 1, wherein the pre-blanking and window mixing circuit is The pre-blanking pulse period is included in the window pulse period, so that the window operation is given priority over the pre-blanking operation. The method of claim 1, wherein the pre-blanking and window mixing circuit is And the main data is output only during a period when the window pulse is high. The method of claim 1, wherein the pre-blanking and window mixing circuit is The pre-blanking and window mixing circuit using the window mixing circuit, characterized in that for outputting the reference voltage without outputting the main data while the window pulse is low.

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