JPH0426255B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention compares input data or blocks with a certain range of data or a set of blocks arranged two-dimensionally, and determines which of the latter is different from the input data. It pertains to a circuit for detecting data or a block with the minimum difference value or the sum of difference values with data within the block and its position, especially when there are two or more data or blocks with the same difference value. The present invention relates to a minimum value detection circuit that can select the data or block closest to the center of the range.

[Conventional technology]

Figure 4 shows a motion compensation encoding method that compresses the band of an image signal and transmits it. Input block data is compared with the optimal block data in the encoding circuit 1 for each pixel, and the difference value is calculated. Generate data. A decoded signal is generated by adding this difference value data and predicted value data predicted according to a certain prediction function from the corresponding pixel data of the previous frame, and the decoded signal is is stored in the frame memory 2 for one frame, thereby generating data for one frame before. The vector detection circuit 3 compares the input block data with the previous frame data from the frame memory 2, generates optimal block data with the minimum difference value from the input block data, and detects the movement from that block. generates vector information indicating the amount and direction of The encoding circuit 1 encodes the obtained difference value data and motion vector information and sends the encoded data to a transmission path.

In this case, in order to minimize the amount of information to be transmitted, in the process of detecting the optimal vector, if there are two or more pieces of data that show the same difference value within a certain range to be compared with the input data, it is necessary to It is necessary to detect data located close to the data.

Conventionally, in minimum value detection circuits for finding such optimal vectors, when there are two or more pieces of data that show the same difference value within the range to be compared with the input data, a comparison is performed to select the data closest to the center. The order of data input to the circuit was arranged in a spiral starting from the center.

[Problem that the invention seeks to solve]

However, in order to achieve such control over the order of data input to the comparison circuit in the minimum value detection circuit, not only is a control circuit required to control data generation required, but also the order of data generation is restricted. Therefore, there was a problem that there was no flexibility in the configuration of peripheral circuits.

[Means for solving problems]

The minimum value detection circuit of the present invention compares the input data with each of the reference data in a certain range, and outputs data whose difference value from the input data is the minimum value within the range and information on its position. At the same time, when there are two or more pieces of data with the minimum difference value from the input data within this range, the comparison selection circuit is controlled to select the data closer to the center of this range.

The configuration of the present invention is as follows.

(1) A subtracter 11 that calculates a difference value from input data and reference data, a comparison circuit 12 that receives the difference value, previous minimum data, and center information as input and calculates a comparison result, and calculates a comparison result between the difference value and the minimum data. A selector 13 receives as input and selects and outputs one of them according to the comparison circuit output, receives position information of the reference data and position information corresponding to the minimum data, and selects and outputs one of them according to the comparison circuit output. By inputting the center information at the same time as the reference data near the center that you want to select preferentially is being input, the selector 14 allows you to input the center information at the same time as the reference data near the center that you want to select preferentially is being input. and a circuit for generating a signal for controlling the comparison and selection circuit so as to select and output data having the smallest difference value from the data, or alternatively, ( 2) An adder 15 and a register 17 are provided after the subtracter 11, and an AND gate 16 is provided for clearing the accumulated value at the beginning of the block, and furthermore, an adder 15 and a register 17 are provided after the selectors 13 and 14 to hold the result in units of blocks. and a circuit for generating a signal for controlling the comparison and selection circuit so as to select and output the minimum difference block in units of blocks consisting of a plurality of data. It has a configuration as a detection circuit.

[Effect]

According to the minimum value detection circuit of the present invention, when there are two or more data showing the same difference value within the range to be compared with the input data, in order to select the data near the center, the comparison circuit compares the data with the input data. The central data can be detected regardless of the order in which the data to be generated are generated, and the data closest to the center can be detected with a simple data generation order.

〔Example〕

FIG. 1 shows the configuration of an embodiment of the minimum value detection circuit of the present invention when the number of data in a block is one. In the figure, 11 is a subtraction circuit;
12 is a comparison circuit, and 13 and 14 are selectors.

In addition, Fig. 2 shows the relationship between input data and reference data, where a represents input data IN,
2 indicates reference data 1 to 9, respectively. In the circuit shown in FIG. Detect.

In FIG. 1, a subtraction circuit 11 subtracts input data and reference data to obtain a difference value B. The comparison circuit 12 compares the minimum data A and the difference value B of the previous comparison results. At this time, when the cascade input CS, which is the central information of the reference data input to the comparison circuit 12, is at a low level, the output C of the comparison circuit 12 indicates that the minimum data A of the previous comparison result is equal to or smaller than the difference value B. It is at a low level. On the other hand, when the cascade input CS is at high level, the output C is the minimum data A of the previous comparison result.
When is smaller than the difference value B, it becomes a low level.

The selectors 13 and 14 select the output S of the comparator circuit 12.
is added as a selection control signal, and input or is selected and output, respectively, depending on whether the output S is at a high level or a low level. In the selector 13, the minimum data of the previous comparison result is connected to, and the difference value output of the subtraction circuit 11 is connected to, and in the selector 14, the position information of the minimum data of the previous comparison result is connected to, and the position information of the reference data is connected to. Therefore, depending on whether the output is high level or low level, one of the pieces of information is output as the minimum data and the position information of the minimum data, respectively. Note that the selector 13,
14 is reset by a reset signal _R1 every frame.

The reference data is sequentially selected and input from the vicinity of the input data, and information about the center of the reference data and position information indicating the position of the reference data with respect to the input data are input.

The generation order of the reference data shown in Figure 2 is 1,
Assuming that the order is 2, 3, 4, 5, 6, 7, 8, 9, the central information of the reference data, that is, the cascade input CS of the comparison circuit 12, is the input B from the subtraction circuit 11, and 2, 4, 5 are If the level becomes high only when the reference data is added, reference data 5 will be selected even if, for example, all nine reference data are the same. However, in this case, the data closest to the center is 5, the next closest data is 2, 4, 6, 8, etc.
The farthest data are considered as 1, 3, 7, and 9.

Regarding the reason why reference data 5 is selected, the above explanation will be further detailed and an operation explanation will be added.

In FIG. 1, the comparison circuit 12 is When CS=0, if A≦B, S=0 If A>B then S=1 When CS=1, if A<B, S=0 If A≧B, S=1 The selectors 13 and 14 operate as follows. When S=0, C= When S=1, C= It operates as follows.

When data 1 is first input as reference data, the signal R1 becomes 1, and the selector selects the side, that is, the difference value and position information of data 1, regardless of the output of the comparison circuit.

When data 2 is input, comparison circuit 1
Even if the CS input of data 2 is set to 1, and the difference value B of data 2 is the same as the difference value A of data 1, S=1, and the side, that is, the information of data 2 is selected.

When data 3 is input, the comparator circuit 12
Since the CS input is 0, S= only when the difference value B of data 3 is smaller than the previous minimum difference value A
1, the side, that is, the information of data 3 is selected, and when they are equal, S=0, and the side, that is, the minimum value up to that point is selected.

When data 4 is input, comparison circuit 1
Even if the CS input of 2 is 1 and the difference value B of data 4 is the same as the previous minimum difference value A, S = 1
Therefore, the side, that is, the information of data 4 is selected.

Even when data 5 is input, comparison circuit 1
Even if the CS input of 2 is 1 and the difference value B of data 5 is the same as the previous minimum difference value A, S = 1
Therefore, the side, that is, the information of data 5 is selected.

From now on, for data 6 to 9, CS=0,
Information for that data is selected only when the difference value for that data is smaller than the previous minimum value.

From the above, if all the reference data are the same, all the difference values are also the same, and data 5 is selected.

Also, the order of generation of reference data is 1, 4, 7, 2,
The same result can be obtained in the same manner when the number is 5, 8, 6, or 9.

Note that if the central data 5 is to be selected when the same data is received elsewhere, the order in which the reference data are generated can be completely arbitrary, and only when 5 is input to the B input of the comparator circuit 12, All you have to do is set the cascade input CS to high level.

FIG. 3 shows another configuration example of the present invention, and shows a configuration for detecting a block in which the sum of the difference values of data within the block is the minimum value. In the same figure, the same parts as in FIG.
19 is a register.

In the case of this embodiment, it is necessary to calculate the sum of the difference values in block units. Therefore, the output of the subtraction circuit 11 is added to the output of the register 17 by the addition circuit 15, and the result is input to the register 17 again. This is repeated within one block.

The output of register 17 is input to comparator circuit 12 and compared with the previous minimum value in register 18. Based on the comparison result, the selector 13 selects the input or, and sets it in the register 18.

Further, the output of the selector 14 is set in the register 19 by a clock in units of blocks. Selectors 13 and 14 output a reset signal R ₁ when the first block is input, that is, at the beginning of the frame.
It is reset by . Also, register 17
Each block is reset by the reset signal _R2 .

〔Effect of the invention〕

As explained above, according to the optimal vector detection circuit of the present invention, input data or a block is compared in size with each of reference data or blocks within a certain range, and a difference value between the input data or the block within that range is determined. In addition to outputting the data with the minimum sum of the difference values of the data in the block and information on its position, the data or block with the minimum sum of the difference values with the input data or the sum of the difference values of the data within the block is output within this range. When there are two or more, the comparison and selection circuit is controlled to select the data or block closer to the center of this range, so the same data or block with the minimum difference value is selected in the range where the data or block should be referenced. When there are two or more data, data or blocks near the center of the range can be selected by a simple data generation order. Furthermore, if the same data or block occurs in addition to the center data or block in the range to be referenced, only the center data or block can be selected, regardless of the order in which the data are generated.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the minimum value detection circuit of the present invention, FIG. 2 is a diagram showing the relationship between input data and reference data, and FIG. 3 is a diagram showing the configuration of an embodiment of the minimum value detection circuit of the present invention. FIG. 4 is a diagram showing a motion compensation encoding method. 1... Encoding circuit, 2... Frame memory, 3
... Vector detection circuit, 11 ... Subtraction circuit, 12
...Comparison circuit, 13, 14...Selector, 15...
...addition circuit, 16...AND gate, 16A...
Or gate, 17, 18, 19... register.

Claims (1)

[Claims] 1. A subtracter that calculates a difference value from input data and reference data, a comparison circuit that receives the difference value, previous minimum data, and center information as input and calculates a comparison result, Take the minimum data as input,
It consists of a selector that selects and outputs either of them according to the comparison circuit output, and a selector that receives position information of reference data and position information corresponding to the minimum data as input, and selects and outputs either of them according to the comparison circuit output, By inputting center information at the same time as reference data close to the center that you want to select preferentially is being input, you can input center information that is close to the center and has a difference value from the input data compared to inputting reference data in any order. A minimum value detection circuit comprising: a circuit for generating a signal for controlling the comparison and selection circuit so as to selectively output the minimum data. 2 After the subtracter, an adder and a register, and a register for clearing the accumulated value at the beginning of the block.
An AND gate is provided, and two selectors are provided after the two selectors to hold the results in blocks.
and a circuit that generates a signal for controlling the comparison and selection circuit so as to select and output a block with a minimum difference in units of blocks consisting of a plurality of data. The minimum value detection circuit according to item 1.