JPS62147872A - Image pickup device - Google Patents

Abstract

PURPOSE:To make the photometry system changeable from the peak photometry system into the average photometry system by dividing a picked-up picture into plural blocks, applying data processing at each block, comparing the quantity of data, extracting an optional number, applying operation processing to apply aperture control. CONSTITUTION:When an image pickup data appears sequentially for the 1st, 2nd line... at a terminal 31, the data are accumulated by a one-horizontal line adder circuit 32, the accumulated data of the 1st line of a block 25A is stored in a storage circuit 33A, the accumulated data of the 1st line of a block 25B is stored in a storage circuit 33B, and so on similarly. When the scanning for the 2nd line is started, the data stored in the storage circuit 33A is fed to the one-horizontal line adder circuit 32, where the data of the 2nd line are accumulated further. Similar processings are applied to the other blocks 25B-25E, and the result of accumulation of all the data in the blocks 25A-25E appears at a terminal 34. Then each block data are stored in a storage circuit 36, an output of a maximum value exchange circuit 37 is fed to a maximum value detection circuit 38, where the maximum value is obtained and fed to an arithmetic means circuit 39. The operations above are repeated and the aperture control data are obtained at a terminal 40.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an imaging apparatus such as a video camera that performs digital processing by AD converting an imaging signal.

2. Description of the Related Art A conventional aperture control circuit for an image pickup apparatus that performs digital signal processing is disclosed in, for example, Japanese Patent Laid-Open No. 68-97969. The conventional device divides the captured image into nine blocks 9A to 9I as shown in FIG. 6(a)K.
The imaging data included in each block is added, and the data for each block is processed by a microcomputer to control the aperture.

FIG. 7 shows a block configuration diagram of this conventional imaging device, in which 1 is a lens, 2 is an aperture device, 3 is an image sensor such as a COD, and 4 is amplified the output signal of the image sensor 3 to a predetermined level. 6 is an AD conversion circuit that digitizes the image signal; 8 is a signal processing circuit that performs signal waveform processing such as gamma correction; and 7 is a signal processing circuit that converts the digitized signal into an analog video signal. 8 is an addition circuit that adds the imaged data; 9 is 1? of the AD conversion circuit 6; Latch circuits that latch data every sample time, 10A, 10B, and 10C are latch circuits that latch data for each block, and the data of each latch is 11A.
, 11B, and 11C to the adder circuit 8 and latch circuit 12. The latch 1oA is for adding data in each of the blocks sA, 9D, and sG shown in FIG. 6(-), and the latch 1oB
is related to blocks sB, 9E, and sH, and latte 1oC is related to blocks 9G', 9F, and 9I.

12 is a latch circuit that latches the added data of each block; 13 is a microcomputer that processes the added data of each block and generates an aperture control signal; 014 is a latch circuit 9.
Latte 10A, -7-10B.

Control signal for latte 1oC, latte 12, latch 9
Clear signal for, game) 11A, 11B.

This is a timing generation circuit that generates a gate signal for 11C.

In the conventional imaging apparatus configured as described above, the formation of average value data for each block will be described.

The first line, the second line according to horizontal scanning from the AD conversion circuit 6
When imaging data appears sequentially as line .
The accumulated data of the first line is the latch 1oA.
Then, after clearing latte 9, the accumulated data of the first line of block 9B is latched in latch 10B, and then the accumulated data of the first line of block 9C is latched into latch 10B. The calculated value is launched into latch 1oC. When the second line scan begins,
The gate 11A is turned on, the data stored in the latte 10A is supplied to the adder circuit 8, and the data of the second line is further accumulated with respect to the accumulated data of the first line of the block 9A. The operations in the other blocks 9B and 9C are similar, and by repeating this operation, the accumulated data of all the blocks 9A appears in the latte 9.
This is taken into the latch 12 and sent to the microcomputer 13. The sum of all the data in blocks 9B and 9C is also generated in the ratte 9 and sent to the microcomputer 13 in the same way. As described above, when the operations related to blocks 9A, 9B, and 9C are completed, similar operations are performed on blocks 9D and 9C.
E, 9F, then 9G, 9H, 9I
A similar operation is performed for .

Next, we will describe the arithmetic processing performed by the microcomputer.

Assuming that the average value data of each of the blocks 9A to 9 blocks formed as described above is Da-D, the microcomputer 13 multiplies these average value data by a coefficient Ka- and adds the result. generates an aperture control signal. In other words, KaDa+KbDb+KoDo+−−−−−−+KiD
Performs arithmetic processing of i. Here, if the coefficients Ka, , , , are set to 0, the data at the top of the screen is made irrelevant. Also, a coefficient K corresponding to the central block 9E.

If only one coefficient is set to 1 and all other coefficients are set to 0, central photometry will be performed. Furthermore, instead of the average value data of each block, the maximum value data of each block may be detected and sent to the microcomputer.

Problems to be Solved by the Invention There are two types of aperture control methods for imaging devices: an average photometry method in which the aperture is controlled using the average value of the image signal, and a peak photometry method in which the aperture is controlled using the peak value of the image signal.

The average 6111 light method is relatively suitable for dark areas when there are both bright and dark areas on the same screen, but the bright areas may become washed out and lose gradation. On the other hand, with the peak metering method, the aperture is set to 1" bright areas, so dark areas that should be sufficiently visible based on the camera's sensitivity may become invisible. In this way, when there are bright and dark areas on the same screen at the same time, the photometry method differs depending on whether the main subject is a bright area or a dark area. In addition, the side lighting method varies depending on the characteristics of the image sensor. For example, when using an image sensor that tends to cause smearing, it is necessary to use a peak photometry method to prevent smearing.

However, in the above-mentioned configuration, since the microcomputer 13 performs weighting by averaging, it is not possible to realize a peak photometry method that controls bright areas on the screen to a constant brightness. For example, if there is a bright part such as a light source and a dark part serving as the background on the same screen, and the bright part is 9 in Figure 6(a),
If it exists in one of the blocks and the remaining blocks are dark, in the conventional method, the aperture is focused on the dark part of the screen to perform averaging, causing the bright part to become blown out, causing the image sensor to In some cases, smearing, blooming, etc. may occur. This was a problem because it similarly occurred even when the microcomputer 13 took in the maximum data of each block.

In view of this point, it is an object of the present invention to provide an imaging device having an aperture control device that can determine the photometry method from the beak 1ll11 light method to the average light metering method.

Means for Solving the Problems The present invention is a device that divides a captured image into a plurality of blocks, processes data for each block, compares the size of data for each processed block, and calculates an arbitrary number of blocks. This is an imaging device that includes an extraction device and a device that performs arithmetic processing on the extracted data to control the aperture.

According to the above-described configuration, the present invention divides an image into a plurality of blocks, calculates the average value or maximum value of the imaging data in each block as data for each block, and compares the size of the data to obtain, for example, a value. The photometry method can be varied from a peak photometry method to an average photometry method by extracting an arbitrary number of large pieces of data and averaging the extracted data to control the aperture and use it as a signal.

Embodiment FIG. 1 shows a block diagram of an imaging apparatus according to a first embodiment of the present invention. In FIG. 1, 1 is a lens, 2 is an aperture device, 3 is an image sensor, 4 is a preamplifier,
6 is an AD conversion circuit, 6 is a signal processing circuit, and 7 is a DA conversion circuit, which is the same as the configuration shown in FIG. 7. 21 is an intra-block data processing circuit that divides an image into a plurality of blocks and calculates and outputs the average value of the imaging data in each block; 22 is a block data processing circuit that compares the magnitude of the data sent from the intra-block data processing circuit 21 and calculates the value. 23 is a block data processing circuit that averages the data sent from the data comparison circuit 22.

As an example of the intra-block data processing circuit 21, FIG.
FIG. 2 shows the case where the image is divided into 26 blocks 25A to 26Y as shown in b). In Figure 2,
AD-converted imaging data is input to the terminal 31 .

Reference numeral 32 denotes a one-horizontal line adder circuit that adds data every sample time of the AD converter circuit 6, and can be constructed in the same manner as the adder circuit 8 and latch circuit 9 in FIG. 33A~3
Reference numeral 3E denotes a memory circuit for storing addition data of each block, and each memory circuit can be constructed in the same manner as the gate circuit 11A and latch circuit 1oA in FIG.

Next, the operation will be explained. Terminal 31 according to horizontal scanning
When the imaging data appears sequentially in the order of line, second line, etc., the one horizontal line addition circuit 32 performs accumulation. The accumulated data of the first line of the block 25A is stored in the memory circuit 33A, and the accumulated data of the first line of the block 25B is stored in the memory circuit 33B.
Similarly, the data of block 2sC is stored in the storage circuit 330, the data of block 25D is stored in the storage circuit 33D, and the data of block 25E is stored in the storage circuit 33H. When scanning of the second line starts, the data stored in the memory circuit 33A is supplied to the one horizontal line addition 3γ circuit 32, and the data of the second line is further accumulated with respect to the accumulated data of the first line of the block 25A. calculated.

The operation in the other 25B, 25C, 26D, and 25E is similar, and by repeating this operation, the accumulated data of all the block 25A appears at the terminal 34. Similarly, 25B, 26C, and 26D
, all the data of 25H is a cumulative male? : The same operation as that for the next block 110 is performed for the next block 110, and finally the summed data for all 25 blocks appears at the terminal 34.

1 of the data comparison circuit 22 and the block data processing circuit 23
As an example, N(
FIG. 3 shows a case in which (a natural number) pieces of data are extracted. In FIG. 3, numeral 36 is a switch, and the terminal S1 is connected to the terminal 34, to which the added data of each block is input. 3
6 is a storage circuit for storing addition data of each block; 38;
is a maximum value detection circuit that finds the maximum value of each block data,
37 is! The maximum value detected by the minister value detection circuit 38 and the data output from the storage circuit 36 are compared, and if the values are the same, zero data is output, and two or more of the same values as the maximum value are output from the storage circuit 36. This is a maximum value exchange circuit that operates to output zero data only once when the data is output, and to output that data in the case of other data. The above constitutes the data comparison circuit 22. 39 is a data comparison circuit 22
The block data processing circuit is composed of an averaging circuit that performs averaging of data supplied from the block data processing circuit.

Next, I will explain the operation. As a first step, the switch 36 is connected to Sl, and zero data is set as the maximum value of the maximum value detection circuit 38. Next, each block data supplied from the intra-block data processing circuit 21 is stored in the storage circuit 36, and when the 26 pieces of data have been stored, the switch 3
Connect 5 to 82. Memory circuit 3 as p52 step
6 sequentially outputs the stored 26 data, and the maximum value exchange circuit 37 outputs the input data as is or as zero data. The output data is sent to a maximum value detection circuit 38, the maximum value is determined, and the obtained data is supplied to an averaging circuit 39. On the other hand, the output data of the maximum value exchange circuit 37 is supplied to the +Ir storage circuit through the switch 26 and replaced with the previous data. 1
Data of 1 is supplied to the maximum value detection circuit 38, and the second step is completed. By repeating the second step N times, N pieces of data are supplied to the averaging circuit 39.
Aperture control data can be obtained at ψ;

As described above, according to this embodiment, the peak photometry method, which could not be realized conventionally, can be realized by setting the number of repetitions of the second step N=1 in the data comparison circuit 22. Furthermore, H
By increasing the value of , it is possible to vary the range from the peak photometry method to the average side light method over 25 steps.

This makes it possible to determine a photometry method that matches the condition of the subject, such as a high-contrast image to a low-contrast image, and the characteristics of the image sensor.

FIG. 4 is a block diagram of an imaging apparatus showing a second embodiment of the present invention. In the figure, 1 is a lens, 2 is an aperture device, 3 is an image sensor, 4 is a preamplifier, 6 is an AD conversion circuit, 6 is a signal processing circuit, 7 is a DA conversion circuit, and 21 is an intra-block data processor p1! The circuit is similar to the configuration shown in FIG. 1.

The difference from the configuration shown in FIG. 1 is that a microcomputer 60 and a switch 51 for data setting are provided.

The operation of the imaging apparatus of the second embodiment configured as described above will be described below. The intra-block data processing circuit 21 supplies the added data DA-DY of each block to the microcomputer as in the first embodiment. The processing of the microcomputer is shown in FIG. 5. In Oa, two setting data H and L satisfying 1≦H≦26 are read from the switch 61. In Ob,
In the OC that reads each block data DA-DY supplied from the intra-block data processing circuit 21, the read D
The 26 pieces of data A to DY are sorted in ascending order of Sl, S2. S
3... In S25 and Od for rearranging, calculate , and obtain aperture control data using block data excluding very bright or very dark parts of the image. At e, the aperture control data is output.

As described above, according to this embodiment, the N:I configuration is simplified by using a microcomputer, and if H=1, by changing the value of L, the N:I configuration can be achieved similarly to the first embodiment. The light metering method can be varied from the ~ri metering method to the average metering method.

Furthermore, in the case of backlighting, in which a main subject such as a person is imaged against the sky, if the aperture is adjusted to the main subject using the above method, the average metering method will be used. However, if the area of the main subject on the screen is smaller than the area of the bright sky on the screen, the average d111 light method cannot adjust the aperture to the main subject because of the data in the bright part of the screen. Therefore, in this case, the microcontroller is L=26
Aperture control is performed by arbitrarily setting the value of H. For example, if H-a, 7 is the largest value in each block data.
Since the average value is calculated using data excluding individual blocks, it is possible to adjust the aperture to the main subject more than in the above-mentioned average metering method.

Note that in the first and second embodiments, the intra-block data processing circuit 21 divides the image into 26 blocks, but this is not limited to 25 blocks.

Further, the intra-block data processing JjljN path 21 may be configured to obtain and output the maximum value of the imaging data within each block.

As described in detail, according to the present invention, the aperture control can be arbitrarily determined from the peak full + light method to the average metering method. 0, which allows you to achieve the optimal photometry method even when using elements.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram of an imaging apparatus according to a first embodiment of the present invention, FIG. 2 is a block diagram of an in-block data processing circuit 21 of the same embodiment, and FIG. 3 is a block diagram of a data ratio 1 of the same embodiment. 4 is a block diagram of the image pickup device of the second embodiment, FIG. 6 is a flowchart of the microcomputer processing of the second embodiment, and FIG. 6 is a diagram of the screen. FIG. 7, a diagram showing block division, shows a conventional imaging device. 2...Aperture device, 3...Image sensor, 2
1...Intra-block data processing circuit, 22...
...Data comparison circuit, 23...Block data processing circuit, 50...Microcomputer, 51...
··switch. Name of agent: Patent attorney Toshio Nakao and 1 other list
1 Figure 2 Section 3 Figure 5 Figure 6

Claims (3)

[Claims] (1) A device that divides a captured image into a plurality of blocks and processes data for each block, a device that compares the size of the data of each processed block and extracts an arbitrary number of data, and An imaging device comprising: a device that performs arithmetic processing on data and controls an aperture. (2) A patent claim characterized in that the device that compares the data of each processed block and extracts an arbitrary number of data extracts an arbitrary number of large-value data from among the processed data of each block. The imaging device according to item 1. (3) The device that compares data for each processed block and extracts an arbitrary number of data is characterized in that the device extracts an arbitrary number of data from the processed data for each block excluding data with large values. Claim 1:
The imaging device described in Section 1.