JPH07168537A - Scanning format converting device - Google Patents

Abstract

PURPOSE:To obtain a scanning format converting device capable of coping with easily even when the number of horizontal and vertical pixels of block pixels are changed by comaring the output of an adder with the whole number of pixels inputted in a first register and by adding a value subtraced with the value of the first register from the value of a second register with an adder. CONSTITUTION:This device is provided with a memory 10 storing temporarily input picture data, a first register 12 storing the whole number of pixels and a second register 14 storing the number of horizontal pixels. Further, the device is provided with third and forth registers 18, 20 storing updated values of read- out addresses and a selection circuit selecting either the third or forth registers 18, 20 by the control of a first counter 16. Moreover, the device is provided with a comparing adder 28 comparing the output of an adder 26 with the value of the first register 12 and performing the addition of a value subtrating the value of the first register 12 from the value of a second register 14 when the output of the adder 26 exceeds the value of the first register 12 and a second counter 30 generating writing addresses.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scan format conversion apparatus for converting image data between a raster scan system and a block scan system in image data scanning, and more particularly to pixels for one line of raster scan system image data. The present invention relates to a scan format conversion device that can relatively easily cope with a case where the number is changed or a case where the number of pixels in the horizontal direction or the vertical direction indicating the size of a block of block scan image data is changed.

[0002]

2. Description of the Related Art A two-dimensional image handled by a television camera, a scanner or the like is generally treated as raster scan type image data in which horizontal scanning is repeated and vertical scanning is performed. On the other hand, in recent image processing techniques, image processing is performed in units of blocks of a predetermined size due to the size of hardware and processing time. That is, block scan system image data is used which performs processing in block units of the horizontal pixel number Bx and the vertical pixel number By.

An example of raster scan image data is shown in FIG.
FIG. 2 shows an example of block scan image data in which the block horizontal pixel number Bx = M = 8 and the block vertical scanning number By = N = 8.

Conventionally, a method using a memory has been used for scan conversion of raster scan image data and block scan image data. That is, the raster scan image data write operation is sequentially performed on the memory, and the block scan image data is read in the block scan scan order. In this case, the write address generation unit and the read address generation unit are configured by hardware such as a counter.

[0005]

However, as described above, when the read address is conventionally configured by hardware, the format of the block scan image data is changed by changing the encoding algorithm (M and N in FIG. 2).
However, there is a problem in that the hardware increases when the value changes. That is, in the conventional configuration, a counter is set for each of the block horizontal pixel and the block vertical pixel to deal with it, but two counters are prepared and the frequency division value is determined for each of them, so the hardware increases. There is a problem.

The present invention has been made to solve the above-mentioned conventional problems, and when the number of horizontal and vertical pixels of a block pixel is changed in the format conversion of raster scan image data and block scan image data. It is another object of the present invention to provide a scan format conversion device that can easily handle the above.

[0007]

SUMMARY OF THE INVENTION The present invention is a scan format conversion device for converting image data between a raster scan system and a block scan system in image data scanning, and a memory for temporarily storing input image data and A first register that stores the number of pixels, a second register that stores the number of horizontal pixels, a first counter that counts the number of horizontal pixels, and third and third that store the updated value of the read address for the memory. 4 registers,
A selection circuit that selects one of the third and fourth registers under the control of the first counter, a fifth register that stores a read address for the memory, an output of the selection circuit, and the fifth register. The output of the adder is compared with the value of the first register, and if the output of the adder exceeds the value of the first register, the value of the second register is The object is achieved by providing an adder for adding a value obtained by subtracting the value of the first register and a second counter for generating a write address for the memory.

[0008]

1 shows an example of scanning raster scan image data and FIG. 2 shows an example of scanning block scan image data.

As shown in FIG. 2, the number of pixels m in one line is m.
(For example, 64) The number of horizontal pixels in one block is M (for example, 8), and the number of vertical pixels is N (for example, 8).

The block scan, as shown in FIG.
It is performed by repeating the following three operations. That is, the first operation to move to the right one by one on the same line, the second operation to move to the beginning of the next line when the end of the same line is reached in the same block, and the last data of the last line of the same block. Is reached, the third operation is to move to the beginning of the next block.

According to the present invention, the above operation is realized as follows.

First, the input image is temporarily stored in the memory, and the total number of pixels (m × N) is stored in the first register as 1
The horizontal pixel number (M) of the block is stored in the second register. The third register stores the amount of change (m-M + 1) for moving to the beginning of the next line in the same block. Next, the first operation is performed by adding the value of the fourth register by the adder and advancing to the right one by one on the same line in one block.

At this time, the number of pixels is counted up by the first counter, and when one line (M) of one block is completed, the selection circuit adds the value of the third register instead of the fourth register. Then, the line is moved to the next line and the second operation is performed.

The above first and second operations are repeated and the output of the adder is compared with the total number of pixels (m × N) stored in the first register to determine the end of reading of one block. Then, by adding a value (M−m × N) obtained by subtracting the value of the first register from the value of the second register, it is possible to move to the beginning of the next block, and the third operation Is done.

The address for accessing the memory is always stored in the fifth register. Further, the write address of the raster scan image data to the memory is generated by the second counter.

As described above, according to the present invention, it is not necessary to use two counters for horizontal and vertical directions as in the prior art, and it is relatively easy to change the size of a block using only the horizontal counter. Can also respond.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 3 is a block diagram showing the schematic arrangement of the scan format conversion apparatus according to this embodiment.

In FIG. 3, 10 is a memory for storing images, 12 is a first register for storing the total number of pixels (m × N), and 14 is a second register for storing the block horizontal pixel number (M). , 16 is a first counter for counting the number of horizontal pixels in a block, 18 is a third register for storing a change amount for moving an address to the beginning of the next line in the same block, and 20 is a same line. Address to the right 1
A fourth register 22 for moving forward, a comparator 22 for selecting one of the registers 18 and 20 according to the value of the first counter 16, and a fifth register 24 for storing an address for reading the block scan image data. Register of 26,
An adder 28 for adding the output of the comparator 22 and the value of the fifth register 24, a value 28 for moving the address to the beginning of the next block if the output of the adder 26 exceeds the total number of pixels (-
(m × N + M) is added, and if not exceeded, a comparison adder that outputs the value as it is, and 30 is a second counter that generates a write address of raster scan image data.

Here, each of the registers 12, 14, 18, 2
Values 0 and 24 can be arbitrarily set according to the block horizontal pixel number M, the block vertical pixel number N, and the pixel number m of one line.

Hereinafter, as shown in FIG. 2, m = 64 and M =
8 and N = 8, a case will be described in which raster scan image data of 64 pixels per line is converted into an 8 × 8 block scan image format.

In FIG. 2, the first register 12 has m
× N = 64 × 8 = 512, the second register 14 has M =
8, the third register 18 has m −M + 1 = 64−8 + 1
= 57. The raster scan image data is sequentially written in the memory 10 at the addresses generated by the second counter 30.

The read address of the memory 10 is given by the output of the fifth register 24. The updating operation of the fifth register 24 will be described below.

Initially, the values of the fourth register 20 and the fifth register 24 are 0, indicating the start address of the first line. The first counter 16 is a counter with a frequency division of 8, and repeats counting from 0 to 7, during which the read address is incremented by 1 in the fourth register 20 to obtain 0.
It increases from 7 to 7. The addition of 1 by the fourth register 20 represents the first operation 2 in FIG. 2 in which the address is advanced right by 1 on the same line. Then, when the value of the counter 16 changes from 7 to 0, the third register 18 is selected by the comparator 22, and the value 57 of the third register 18 is added to the value 7 of the address at that time to obtain 7 + 57.
= 64, the address becomes 64, and the leading data of the second line is designated and read. The second operation 4 in which the portion for adding the value m-M + 1 (57 in this embodiment) of the third register 18 advances the address to the beginning of the next line
Represents

By repeating the same operation and adding the value 57 of the third register 18 to the last data address 455 of the eighth line, 455 + 57 = 512. But,
Since the total number of data is 512 or more, the first register 12 and the second register 14 pass through the adder 28 to
m × N + M = −512 + 8 is added to obtain 512 + (− 5
12 + 8) = 8 results in address 8, which indicates the address of the first data in the upper left of the next block, as shown in FIG. This represents the third operation 6 in FIG.
In this way, the process proceeds to the next block, and the same process is repeated thereafter. Even when the block scan image data is not 8 × 8 as in the present embodiment but another value M × N, it is easy to set a predetermined value in each register 12, 14, 18, 20. It is clear that the same process is carried out.

[0026]

As described above, according to the present invention, the generation of the read address of the block scan image data can be easily constituted by the counter, the register, the adder and the comparator, and the counter for the block horizontal image data only. This has the effect that the configuration is possible by determining the frequency division value of. The block scan data also has an excellent effect that it can be arbitrarily determined by determining the total number of images and the number of block horizontal pixels.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the concept of raster scan image data.

FIG. 2 is an explanatory diagram showing the concept of block scan image data.

FIG. 3 is a block diagram showing a schematic configuration of a scan format conversion apparatus according to this embodiment.

[Explanation of symbols]

 10 ... Memory 12 ... 1st register 14 ... 2nd register 16 ... 1st counter 18 ... 3rd register 20 ... 4th register 22 ... Comparator 26 ... Adder 28 ... Comparison adder 30 ... 2nd Counter

Claims (1)

[Claims] 1. A scan format conversion device for converting image data between a raster scan system and a block scan system in image data scanning, a memory for temporarily storing input image data, and a first memory for storing the total number of pixels. A register; a second register for storing the number of horizontal pixels; a first counter for counting the number of horizontal pixels; third and fourth registers for storing an updated value of a read address for the memory; A counter circuit for selecting one of the third and fourth registers, a fifth register for storing a read address for the memory, an output of the selector circuit and an output of the fifth register. An adder for adding, comparing the output of the adder and the value of the first register,
If the output of the adder exceeds the value of the first register, an adder for adding a value obtained by subtracting the value of the first register from the value of the second register, and a second address generating a write address for the memory The scan format conversion device, which is equipped with a counter of.