JPH0324861A - Picture memory access method - Google Patents

Abstract

PURPOSE:To improve the using efficiency of a picture memory by using a point, which scanning from the origin reaches with the overall length in the horizontal direction of a picture memory as the scanning width, as the coordinate point corresponding to a picture element. CONSTITUTION:When a maximum length of the x-direction address of input picture element data, the y-direction address if input picture data, and the x- direction address of input picture data are denoted as X length, Y, and A respectively, an address AD on a picture memory 3 of input picture data is given by AD=(X length)XY+X to access the picture memory 3, thereby eliminating the x-direction unused area of the picture memory. With respect to conversion of the expression, the overall length of the scanning line to a point (picture element) of coordinates (X,Y) which raster scan of input picture data from the origin with the x-direction scanning width X length reaches is equalized to the overall length of the similar scanning line to the picture element on the picture memory (consequently, the address AD of the picture element). Thus, the using efficiency of the picture memory 3 is improved.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an image memory access method in an image processing device, an image editing device, etc., and more particularly to an image memory access method that eliminates unused areas of the image memory and improves the usage efficiency of the image memory. Note that in the following figures, the same reference numerals indicate the same or corresponding parts.

[Conventional technology]

In the image processing apparatus, the address AD of a point (pixel) on the image memory is configured as shown in FIG. 3 in order to speed up the processing. That is, if the position of a point on the image memory is represented by two coordinate values in the horizontal direction (X direction) and vertical direction (y direction), each coordinate value is represented by a χ address. If the Y address is used, the address AD of the point in image processing is
is expressed in the form of a single numerical value that is a combination of an X address and a Y address. That is, in this example, of the total 28-bit address AD, the upper 16 bits indicate the Y address, and the lower 12 bits indicate the X address. The total value of this address AD is the total length of the scanning line when the image memory is raster scanned from the origin (the point where both X and Y addresses are 0) to the point (pixel) in question. They have the property of being equal. FIG. 4 shows the arrangement of conventional input image data areas on an image memory map, and the X-direction addresses OH to O FOOH, which include input image data as shown in FIG. 3 (^),
The addresses on the image memory map of the area of the y-direction addresses OH to I Fool are represented by the portion excluding the shaded portion in FIG. 3(B). The numerical values on this figure (B) indicate the coordinates of the point in question in the configuration of the address AD in Figure 2. For example, the numerical value I FOOOOOOOH of the point (pixel) of P is the coordinate of the input image data for this point P. Y coordinate is IFOOH
, indicates that the X coordinate is 000H.

[Problem to be solved by the invention]

The maximum address in the X direction of image data that can be input to the image memory accessed by the address shown in FIG. 3 is 2I! It is. For example, if you want to input image data drawn on B4 paper into the image memory, this paper should be
When divided by i, the X direction address is 4096 = 2 Iz
(I000H), y direction 7'}'L/, 2. is 5732
(1664H), and the X direction address becomes 2fi. The image data area of this B4 paper is represented on the image memory by the address area shown in FIG.
All areas from ~1633FFFH are used. However, when inputting image data drawn on A4 paper into an image memory similar to the above, this paper is
When divided by pi, the X direction address is 3456 (O
D80H), and the y-direction address is 4677 (1
245H). The image data area of this A4 paper is represented on the image memory by the address area shown in FIG. 6, and uses areas 0 to 1244FFFH of the image memory. In other words, approximately 2.3M bytes of memory is required, of which 280H bits x 1245H bits or 0.3
5M bytes (shaded area) is an unused area. In this way, if the maximum possible value of the address in the X direction of the input image data is not 2'', there is a problem that an unused area will generally occur in the image memory.In the case of the above example, the actual problem is that the Memory implementation is I
Considering the fact that the image data is in units of M bytes and 2 M bytes, a memory of 3 M bytes is required to store image data for an A4 sheet of paper. Moreover, this unused area is 28
Since it is a 0H bit and occurs every OD80H bit, it is difficult to use it as a table or buffer. Therefore, an object of the present invention is to solve the above problem by providing an image memory access method that accesses the image memory using an address obtained by converting the coordinates of image data to be input by a predetermined calculation. .

[Means to solve the problem]

In order to solve the above-mentioned problems, the method of the present invention provides a method for scanning and inputting a horizontal address (hereinafter referred to as X address) and a vertical direction address (hereinafter referred to as Y address) as coordinates (via image scanner 01, etc.). In the image memory access method for storing image data in an image memory (such as 3), the maximum value of the X address of the image data (Xle-ngt
h) is the horizontal scanning width, and the total length of the raster scan from the origin to the point of the pixel in question (
(X length) X Y + The address (AD, etc.) of the coordinate point is determined using the X address and Y address so that the coordinate point is a corresponding coordinate point.

[Function] The present invention provides the maximum length of the X-direction address of input pixel data:
th Y-direction address of input image data: Y X-direction address of human-powered image data:
By accessing the image memory as +X-----(1>), the unused area of the image memory in the The total length of the scanning line from the origin to the point (pixel) at the coordinates (X, Y) is the scanning width of It is made to be equal to the total length of the line (therefore, the address AD of the pixel).

【Example】

Embodiments of the present invention will be described below based on FIGS. 1 and 2. FIG. 1 is a block circuit diagram showing the structure of an embodiment of the present invention. In the figure, 01 is an image scanner that scans an image to be input, and converts the X-direction address X. A y-direction address Y and data DATA regarding the pixel are given to the input/output device 1. When inputting this image data to the image memory 3, the CPU core block 7 of the input/output device 1 outputs the addresses X and Y for each pixel to the arithmetic circuit 2, and also outputs the chip select signal 15 to input the image memory 3. Then, the write signal 13 is applied to the buffer 8 and the image memory 3, and the data DATA of each pixel is inputted to the image memory 3 via the buffer 8. At this time, the arithmetic circuit 2 uses the input addresses X and Y to access the address A of the image memory 3.
D is determined according to the above equation (1) and output to the image memory 3. In this way, the data DATA of the pixel is stored at the location indicated by the address AD on the image memory 3. However, prior to the above calculation of the arithmetic circuit 2, the CPU core block 7 in the input/output device outputs the chip select signal 16, selects the multiplier 9 in the arithmetic circuit 2, and selects the X-direction address X of the input image data. Set the maximum length X length. When calculating the above formula (1), the multiplier 9 in the calculation circuit 2 calculates the maximum length Xlength of the set X-direction address.
and the y-direction address Y, and outputs (X length) X Y as the result of the operation to the adder 10. The adder 10 adds the multiplication result and the X-direction address X, and accesses the image memory 3 using the address AD as the addition result. In this way, when the image data on the A4 paper described in FIG. 6 is manually input to the image memory 3, Xlength =
O D80H, and the input image data area of FIG. 2(A) fits into the area of FIG. 2(B) in the image memory 3.
There is no unused area in the image memory. In this case, Y=
The address AD on the image memory 3 for the point (pixel) P1 at the coordinates IH, X=OH is
D = O D80H, and this point is shown in the same figure (B)
is indicated by point P1. Similarly, in the same figure (A) on A4 paper, Y = 1244H, X = O D7
Address A on image memory 3 regarding point P2 of Fl{
D is given by AD=F6837FH, and this point is indicated by point P2 in the same figure (B).

【Effect of the invention】

According to the present invention, the image memory is accessed to store image data scanned and input using a horizontal address (hereinafter referred to as X address) and a vertical direction address (hereinafter referred to as Y address) as coordinates in the image memory 3. In the method, a maximum value X l of the X address of the image data
A raster scan scan of a length equal to the total length of the raster scan scan from the origin to the point of the pixel in question, with eng-th as the horizontal scan width, is performed on the image memory 3 in the horizontal direction of this image memory. Using the X address and Y address, set the address AD of the coordinate point to AD= (X
length) XY + Can be done. For example, in order to store A4 size image data in an image memory, the image memory used to be 3 MB AD: Image memory? }'Shisu 3 figure O 4 figure

Claims (1)

[Claims] 1) The image memory for storing image data scanned and input using a horizontal address (hereinafter referred to as X address) and a vertical direction address (hereinafter referred to as Y address) as coordinates in the image memory. In the access method, a raster scan scan of a length equal to the total length of a raster scan scan from the origin to the point of the relevant pixel is performed, with the maximum value of the X address of the image data as the horizontal scan width. On the memory, use the X address and Y address to set the coordinate point corresponding to the pixel so that the point reached by going from the origin using the entire horizontal length of the image memory as the scanning width is the coordinate point corresponding to the pixel. An image memory access method characterized in that the address of the image memory is determined.