JPS5819074A - Dot pattern generating method for picture processing - Google Patents

Abstract

PURPOSE:To clearly record a character pattern, by scanning a character region with an image sensor, and generating a pattern consisting of white and black dots corresponding to changing points regardless of the density of paper, when dark and bright changing points are detected. CONSTITUTION:If the difference of density between paper and print is small, a character pattern of a character region is scanned 2 to obtain the density distribution and a changing point 5 from bright and dark and a changing point 6 from dark to bright are obtained. A pattern 7 black at the right half and white in the left half corresponding to the changing point 5 and a pattern 8 black in the left half and white in the right half corresponding to the changing point 6 are generated. If bright parts are consecutive, a pattern 9 consisting of gray dots corresponding to the density of paper is generated and if dark parts are consecutive, a pattern 10 consisting of black dots is generated. Thus, through the generation of patterns like this, a white part 11 is obtained along the profile of the character pattern. Then, even if the difference of density between paper and print is small, the profile of character lines is made clear.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a method of expressing gradation by associating multiple dots with one pixel of a gradation image, and is capable of printing text on a low-contrast character document recorded on a paper surface with a high background density. This invention relates to a dot pattern generation method that can record characters with high intelligibility.

As shown in Figure 1, this type of conventional method scans a character area with an image sensor, detects changes from light to dark or from dark to light, and generates a black right-aligned or left-aligned pattern. was. If this method is used, as shown in Figure 2, the problem will occur for originals with low contrast and ground density, such as originals recorded on blueprints or originals recorded on colored paper. The dot pattern t consists of gray and black, and the difference in density at the outline of the characters becomes small, making it impossible to record the characters clearly.

In order to eliminate these drawbacks, the present invention scans a character area with an image sensor and detects a change point from bright to dark or dark to light, and then displays white and black corresponding to the change point regardless of the paper density. It is designed to generate a pattern consisting of dots, and will be explained in detail below using the drawing buttons.

FIG. 3 is a diagram showing the principle of the present invention, where 1 is a character pattern;
2 corresponds to the scanning direction of the image sensor, 3 corresponds to the Kawahara temperature, 4 corresponds to the print density, 5 corresponds to the change point from bright to dark in the two scanning directions, 6 corresponds to the change point from dark to light, and 7 corresponds to change point 5. 8 is a pattern corresponding to change point 6, 91d is a pattern corresponding to light (paper density), pattern corresponding to 10 shades darker (print density), 11 shades white density. The example in Figure 3 is representative of the case where a 2-dot (IX2) dot pattern is made to correspond to the 11!11i elements of the original image.
4 dots (2X2), 8 dots (2X4), 9 in 1 pixel
The same applies when matching dots) (3×3), etc.

Method 1: Expressing gradations by associating multiple dot patterns of 111 pixels (white, gray, black) in a single image of gradation (if the paper is unprinted or colored, it is not possible to There are cases where the difference between the dark color and the printing acidity is small. In such cases, in order to record the character pattern in the character area, scan 2 is first performed on the character pattern in the character area. Scan 2 changes the density distribution. obtained, paper density 3, print density 4, change point 5 from light to dark in the two scanning directions, and change point 6 from dark to light.
is found. Based on this density distribution, a pattern 7 is generated in which the right half is black and the left half is white, corresponding to the change point 5, and a pattern 8 is generated in which the left half is black and the right half is white, corresponding to the change point 6. . If the light is continuous, a pattern 9 in which all the dots are made of gray corresponding to the paper density is generated, and if the dark is continuous, a pattern 10 in which all the dots are black is generated. By generating the pattern in this manner, the white portion 11 is obtained along the outline of the character pattern. As a result, even when the difference between the paper density and the print density is small, the outline of the character line is clearly defined.

FIG. 4 shows an embodiment of the present invention, in which 12 is an image memory for a character area, 13 is an address register for reading data from the memory 12, 14 is a shift register consisting of two registers, 15 is an &clusiva OR circuit, 16 is a comparator, 17 is a storage memory for the value 111 indicating black, 18 is a pattern 8 generation circuit, 19 is a pattern 7 generation circuit, 20 is a comparator, 21 is a butter 29 generation circuit, and 22 is a pattern 10 generation circuit.
A generating circuit 23 is an output buffer memory, 24 is a signal for increasing the contents of the register 13 by 1, and 25 is a circuit for binarizing into black (=1) and non-black (=0). In the operation of this circuit, first, density information of a character area is stored in the memory 12. As shown in FIG. 4, each line of li! The concentration information of the Ii element is read out one by one from left to right, binarized in a binarization register 25, and stored in R2 of the shift register 14. At this time, the information of the previous pixel, which was already stored in R2, is shifted to R1. Contents of R1 and R2 i'j: k
If the contents of R1 and R2 are different, the comparator 16 is activated. Comparator 1
6, R1 information and notes! Comparison is made with the black value (-1) stored in advance in 717, and when R1 is "1" (black), pattern 8 is selected, and when R1 is not 11' (paper density is 3), pattern 8 is selected. Pattern 7 is generated in circuits 18 and 19, respectively. l! 'aolusive OR circuit 1
5, if it is determined that the contents of R1 and R2 are equal, the comparator 20 is activated.

The comparator 20 uses the information of R2 and the black ta from the memory 17.
When R2 is not "] arm, pattern 9 is generated, and when it is '11, pattern ]O is generated in circuits 21 and 22, respectively. Here, pattern 9
It is assumed that the density corresponding to gray has been detected in advance.

The pattern generated by the circuit 18, 19, 21 or 22 is stored in the output buffer memory 23, and recording is performed when one line of storage is completed. 24 to the register 13, its contents are incremented by 1, and the value of the next stroke in the memory 12 is binarized by the binarization circuit 25 and read out to R2. By the above-described operation, the output cover turn as shown in FIG. 3 can be generated.

As explained above, since white dots are always generated in contact with the outside of the outline of a character, there is an advantage that the entire character pattern recorded on paper with high density can be clearly recorded.

[Brief explanation of the drawing]

Fig. 1 shows a conventional method for generating dot patterns for character patterns, Fig. 2 shows dot patterns when paper density is high using the conventional method, Fig. 3 shows the principle of the present invention, and Fig. 4
The figure shows an example of the present invention. In the figure, 1 is a character pattern, 2
is the scanning direction of the image sensor, 3 is the paper density, 4 is the print density, 5 is the change point from bright to dark in the two scanning directions, 6Id
: Change point from dark to light, 7 corresponds to a pattern corresponding to change point 5, 8 corresponds to a pattern corresponding to change point 6, 9 corresponds to a pattern corresponding to light (paper density), 10 corresponds to dark (print density) 11 is the density of white. Patent Applicant: Nippon Telegraph and Telephone Public Corporation Patent Attorney Mori 1) Hiroshi Figure 3 Figure 4 Procedural Amendment (Method) February 22, 1980 Commissioner of the Patent Office Shima 1) Haruki Tono Hayashin 1, Indication of the Case Patent Application No. 117241 of 1988 2, Title of Invention Dot pattern generation method for image processing 3,
Relationship with the case of the person making the amendment Patent applicant Address: 1-1-6 Uchikara-cho, Chiyoda-ku, Tokyo Name (
422) Nippon Telegraph and Telephone Public Corporation Representative Tsune Shinfuji 4, Agent 6 Number of inventions to be increased by amendment t, cL8, Contents of amendment Contents of amendment as attached (1) Page 7 of the specification, line 2 “Pattern "Generation method" is corrected to "Explanatory diagram of pattern generation method." (2) Correct "Dot pattern" in the third line of page 7 of the specification to "Dot pattern explanatory diagram." (3) ``Example'' on page 7, line 4 of the specification shall be amended to ``Example configuration diagram.'' (4) The characters [Original pattern], [Density distribution], [Generation pattern], and [Output density distribution] in Figure 3 of the drawing are erased as shown in Figure 1. that's all

Claims (1)

[Claims] In this method, multiple dots correspond to one pixel of image information, and the area of three values of white, gray, and black is changed to express gradation. If the right side is dark, align the black dots to the right and the white dots to the left. If the right side is brighter than the left, align the black dots to the left and the white dots to the right. Image processing that generates a pattern, in which all dots corresponding to the paper density generate a gray pattern when light is continuous, and all dots generate a black pattern when darkness is continuous. Dot pattern generation method for.