JPH03276976A - Video camera - Google Patents

Abstract

PURPOSE:To simplify the hardware by dividing a 2-dimension picture into plural blocks, detecting a maximum value for each block, multiplying a desired coefficient with the maximum value and controlling an iris based thereon. CONSTITUTION:An output of an image pickup element 1 is converted into a data of one sample 8-bit by an A/D converter 10 and fed to an adder 11. The output of the adder 11 is fed to registers 13A, 13B, 13C of equal number to the number of division in the horizontal direction and a delay circuit 12 with a delay by one sample. The output of the circuit 12 is fed to the adder 11 and outputs of the registers 13A-13C are fed to the adder 11 and a latch 15 via gates 14A, 14B, 14C. The sum output for each block obtained from the latch 15, that is, the mean data is fed to a microcomputer 19 and an iris control signal is generated by multiplying a prescribed coefficient with the mean data and adding the result. The signal is fed to an iris device 2 and the iris is adjusted to a value in response to the iris control signal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to video cameras, such as digital video cameras.

Auto iris adjustment of conventional video cameras has been performed using the configuration shown in FIG. In the figure, reference numeral 1 denotes an image sensor made of, for example, a CCD, 2 an iris device, and an output from the image sensor 1 is guided to an output terminal 5 via an amplifier 3 and an AGC circuit 4. The iris device f2 is constituted by a motor or the like, and is configured to automatically set the iris according to an iris control signal. At the same time, the output of the AGC circuit 4 is supplied to the peak detection circuit 7 via the gate circuit 6, and the iris device 2 and the AGC circuit 4 are controlled by the output of the peak detection circuit 7. As shown in FIG. 2, the gate pulse generator 8 supplies the gate circuit 6 with a gate pulse that causes a gate-off period of about 173 times, which is one field (1) period.

The same thing as the above-mentioned iris control can also be applied to a digital video camera, by multiplying the data corresponding to the gate pulse shown in FIG. 2 by the camera output, and finding the peak value or average value of the output. The iris device can be controlled by this. However, in order to do this, it is necessary to add data for one screen, and the number of bits of the addition result increases, resulting in a disadvantage that the hardware becomes large-scale. In addition, if processing can be performed using a microcomputer, the circuit size can be reduced, but since the data processing speed of a microcomputer is slower than the video data transmission rate, the gate and peak detection (or average value detection) processing described above is unnecessary. It is possible.

This invention makes it possible to generate control signals for iris control and gain control by processing the output of a digital video camera using small-scale hardware such as a microcomputer.

An embodiment of the present invention will be described below.

In this example, as shown in Fig. 3, the captured two-dimensional image is divided into nine blocks 9A to 9I, the video data included in each block is added, and the data for each block is It is sent to the microcomputer for processing.

FIG. 4 shows the configuration of an embodiment of the present invention, in which the output of the image sensor 1 is converted by an A/D converter 10 into video data of, for example, 8 bits per sample, and an adder 11
is supplied to The output of the adder 11 is supplied to a delay circuit 12 with a delay amount of one sample and registers 13A, 13B, and 13C in a number equal to the number of horizontal divisions. The output of this delay circuit 12 is supplied to the adder 11, and the outputs of registers 13A, 13B, 13C are supplied to the gate 14.
Adder 11 and latch 15 via A, 14B, 14C
is supplied to This register 13A is the block 9A,
The register 13B is for generating the addition output of the data included in each of blocks 9D and 9G.
, 9E, and 9H, and register 13C is related to block 9C.

This is related to 9F and 91. Further, 16 indicates a decoder, to which each output of a horizontal counter 17 and a vertical counter 18 is supplied. And decoder 16
, clear pulse to delay circuit 12, register 1
Control pulses for 3A, 13B, 13C, gate 14
Gate pulse for A, 14B, 14C, latch 15
A latch pulse is generated for

The summed output for each block, that is, average value data obtained from the latch 15 is supplied to the microcomputer 19, and data processing is performed according to a predetermined program.

The average value data of each of blocks 9A to 9■ is Da to Di.
Then, the microcomputer 19 generates an iris control signal by multiplying these average value data by a coefficient K + ``'''' K 9 and adding the result.

In other words, (KI Da+! Db+Ks Dc+,
---...10, perform the arithmetic processing of Di), here on the coefficients.

If KO, NI, are set to 0, then the 173 data at the top of the screen are made irrelevant. Furthermore, if only the coefficients corresponding to the central block 9E are set to 1 and all other coefficients are set to 7:0, central photometry will be performed.

What kind of processing the microcomputer 19 performs is determined by the program. A control signal generated from the microcomputer 19 is supplied to the iris device 2, and the iris value is adjusted according to the level of the control signal.

The formation of the average value data for each block described above will be described in detail. From the A/D converter 10, the first
When video data appears sequentially in the line, second line, etc., the adder 11 performs accumulation. Then, the accumulated data of the first line of block 9A is set in the register 13A, and then the delay circuit 12 is cleared, and then the accumulated data of the first line of block 9B is accumulated by the same operation. The accumulated data of the first line of block 9C is set in register 13G. Second
When a line of data is generated, gate 14A is turned on, and the data stored in register 13A is supplied to adder 11, and the accumulated data of the first line in block 9A is applied to the accumulated data of the second line. Data is further accumulated.

The operations in other blocks 9B and 9C are similar,
By repeating this operation, at a predetermined timing, the accumulated data of all the blocks 9A appears at the output of the delay circuit 12, which is taken into the latch 15 and sent to the microcomputer 19. Further, the accumulated data of all the data of blocks 9B and 9C is also generated at the output of the delay circuit 12 at a predetermined timing, and is sent to the microcomputer 19 via the latch 15. When the above operations for blocks 9A, 9B, and 9C are completed, similar operations are performed for blocks 9D, 9E, and 9F.
and then block 9G.

Similar operations are performed for 9H and 9I.

Note that, different from the above embodiment, the maximum value data may be detected for each block and sent to the microcomputer.

As mentioned above, in this invention, the screen is divided into multiple blocks, the average value or maximum value for each block is formed, and this is calculated by a microcomputer, etc., so the data rate is reduced and the hardware is simplified. At the same time, it becomes possible to process using a microcomputer.

Note that the present invention may be applied to gain control that extracts only data in the center of the screen, such as when adjusting white balance.

[Brief explanation of the drawing]

Fig. 1 is a block diagram used to explain a conventional video camera, Fig. 2 is a waveform diagram of its gate pulse, Fig. 3 is a route diagram showing screen division in an embodiment of the present invention, and Fig. 4 is a diagram of the present invention. FIG. 2 is a block diagram of an embodiment of the present invention. 1...Image sensor, 2...Iris device, 9A to 9I...Block, 11...
...Adder, 13A, 13B, 13C...Register, 19...Microcomputer.

Claims (2)

[Claims] (1) A detection means that divides a two-dimensional image captured by an image sensor into a plurality of blocks and detects the maximum value of image data for each block, and an image corresponding to the maximum value of image data for each block. A video camera comprising control means for multiplying each data by a desired coefficient and controlling an iris based on each image data after the multiplication. (2) A detection means that divides a two-dimensional image captured by an image sensor into a plurality of blocks and detects the maximum value of image data for each block, and an image corresponding to the maximum value of image data for each block. A video camera characterized by comprising a control means for multiplying each data by a desired coefficient and controlling the level of the output signal of the image sensor based on each image data after the multiplication.