JPS61214666A - Image outputting system - Google Patents

Abstract

PURPOSE:To reproduce a half tone image of high quality, and to output a character and a line drawing of high quality by dividing a picture element of a picture element matrix into (m) pieces of elements in the scanning line direction, and outputting an optional element in (m) pieces of elements, in one picture element. CONSTITUTION:One picture element 6 to be recorded is divided again, divided into plural pieces of microscopic picture elements 10, and an one picture element 6 is divided into five pieces of microscopic picture elements 10. A main scanning direction of a beam scan is taken in the direction (x), and the light emitting pulse width of light in one picture element is divided into five. In a printer of a heat transfer system by a thermal head of a fullstable multivibrator, when the thermal head is arranged in the direction (y), a hexadic output can be obtained in the same way by changing the applied pulse width of each head in the feed direction. In case of outputting a character of 'A', it is considered that coordinates (x0, y0)-(x4, y4) of each apex 30-34 have been given, the picture element of the periphery of the apex 31 is displayed in accordance with a 3X3 picture element matrix 35. In this way, a gradation picture of high quality can be reproduced, and a character, a line drawing, etc. of high quality can be outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Technical Field The present invention relates to an image output method for outputting both gradation image information, character information, etc. with high quality.

Conventionally, it has been difficult to output both image information, especially image information with halftones, and fonts such as characters in high quality because the methods are different from each other and the cost performance is poor, so it is not practical in many cases. For example, when it comes to characters, if you use a bitmap character font such as 32 The jagged edges are noticeable and the quality deteriorates. Furthermore, if a high-resolution character font is to be used for a large number of characters, a large capacity font memory is required, which is extremely expensive.

On the other hand, in halftone images, in order to reproduce gradations,
It is common to use dither method or density pattern method,
A small teaser matrix size does not provide sufficient gradation, and a large matrix must be used, which reduces resolution and makes striped patterns noticeable due to the periodic structure of the matrix, making it difficult to output high-quality gradation images. The problem was that it was difficult.

An object of the present invention is to provide an image output method that eliminates these drawbacks and enables reproduction of high-quality halftone images and output of high-quality characters and line drawings.

Examples Hereinafter, one embodiment of the present invention will be described based on the drawings.

Figure i1 shows an example of the high multilevel W power of this embodiment, in which one pixel 6 to be recorded is subdivided into a plurality of fine pixels lO
Figure 0 shows an output method in which one pixel 6 is divided into five fine pixels 10, that is, one pixel 6 is output as six pieces.This output method is used, for example, in a laser beam printer. This can be obtained by setting the main scanning direction of the beam scanning in the X direction and dividing the width of the light emission pulse in the L element into five parts. In a thermal transfer printer using a full multi-thermal head, the thermal head is moved in the X direction, and by changing the pulse width applied to each head in the feeding direction (X direction), six-value output can be achieved in the same way. Obtainable.

Figure 2 (,A) shows the output state of the conventional multi-level (Iff) output.In the case of six-value output, the (,A)
An example is shown in which five levels of gradation output (six levels including all white) are obtained per pixel by increasing the thickness of the fine pixels 10 in the direction from 1) to (5).

In this embodiment, as shown in FIG. 2(B), 175
Assume that the state corresponding to the pixel width can take five states as shown in the figure. Therefore, in the case where two fine pixels 10 having a width of 115 pixels emit light as shown in FIG. 2(C), only the state <pc2=10 exists as shown in the figure. Similarly, when there are three fine pixels, tc3=io, . . . , the number of states becomes extremely large, and the degree of freedom increases. Therefore, the total number of states at this time is Σ
C1=25=32.

In this example, each micropixel emits light (or prints) arbitrarily in this way.
It is configured as possible to realize multivalue. However, in general, as the number of states increases, the amount of information increases accordingly, the amount of data for indicating the states increases, and control tends to become more complex. However, in this embodiment, as described below,
This method makes it possible to implement the above-mentioned method using the same data capacity as ordinary binary data.

FIG. 3 is a diagram showing a case where a character is output, and the figure illustrates a case where a part of the character "A" is output. Here, the coordinates of each vertex 30 to 34 (Xo, '10)
.about.(Xa l 74 ) is given, of the pixels of the dot to be printed, especially the pixels around the vertex 31 are displayed in correspondence with the 3×3 pixel matrix 35.

FIGS. 4(A) and 4(B) show how the data of the straight line connecting the vertices 30 and 32 passing through the pixel matrix 35 is fleshed out.

(A) shows the case where thin filling is applied, and (B) shows the case where thick filling is applied. This amount of filling makes it possible to correspond to various fonts and suppress the occurrence of jaggedness on diagonal lines.

Furthermore, as shown in FIG. 2(C), the straight line 36 can be converted into a continuous and easy-to-read output by blackening the fine pixels through which the straight line 36 passes, and also blackening the fine pixels 37 that are somewhat distant from it. The applied signal at the AA' cross section in (C) is shown in Figure 2 (D).In the case of a laser beam printer, scanning is performed with a finite laser spot diameter (the laser spot diameter is approximately the size of one pixel). The light energy distribution due to scanning is as shown in Figure 2 (E), where the blackening density is high at the center and low at the periphery.

Therefore, it appears as a smoother continuous diagonal line.

FIG. 5 shows a method for determining the coordinates of the center position of such fleshing. The two coordinates of the end point of the straight line 36 are point A (Xo, Vo, fLo) and point B (X2
, 72 r sentence 2).

(However, here, it is assumed that the distance in the X direction is measured from the left edge of the pixel within one pixel.) At this time, the coordinates (xi, yi, JLi)jt that this direct @36 passes through are as follows. Find out.

Converted coordinates of point A (XA, YA) = (xo + sentence o, yo) Converted coordinates of point B (XB, YB) = (X2 +12.72) Equation of line 36 % Formula % By giving yt from the formula The values of Xi are found sequentially.

However, the number of yi is an integer value between yo and y2.

Once such Xi is found, xi and Jli can be separated as follows. Now, let Xi be an integer value, and 9. For example, if i has 6 values, it can take on 5 values of 015.115.215.315.415, then xi=[Xi]...
・(2) However, "L" is a Gaussian symbol that indicates only the integer part.
Set i to take the closest value between 015 and 415 in the decimal part. As a result, it is possible to determine which fine pixel out of one pixel the straight line passes through.

By repeating the above operations (xi, yi).

The value of li) can be found for the deviation of the integer value yi between yo and y2.

FIG. 6 shows the flow of the above method. First, in step SL, (xo * Vo , lo) + (X2
, 72 , S2) is input. Here y.

<yt 0 Next, proceed to step S2, and yO<y
For integer yi such that i < y 2, Xi.

Find the standing i. In step S3, six sentences are determined based on each font information. That is, as shown in FIG. 4(C), this refers to a process of arranging fine pixels 37 to reduce jaggedness.Next, the process proceeds to step S4, and yt is incremented by +1. In step S5, it is checked whether the value of yi has become equal to yt, that is, whether the processing for the straight line has been completed.

If the processing is not completed, the process returns to step S2 and the above-described operations are executed.

By repeating the above steps, you can output characters in any font style. This method performs real-time calculations using a CPU, etc., and transfers the image to the memory (not shown). Therefore, just by having vector data, the light emitting part of a multivalued micropixel can be calculated by calculation. The data capacity is much smaller than having a high-resolution character pattern in a bitmap font (bit image), and it can flexibly respond to changes in fonts.

FIG. 7 shows an output method for a halftone image. It is assumed that the 0 image data 14 is, for example, digitized 8-bit data. RO that stores the dither threshold
A dither threshold value based on the systematic dither method is periodically outputted from M13, and is compared with image data 14 by a comparator 11. As a result of the comparison, it is outputted as an Oor I binary output signal 12.

The multivalue conversion method in this example is shown in Fig. 8 (A) and (B).
This is done using the threshold matrix shown in . Figure 8 (
A) shows an example of a dot concentration type screen, and FIG. 8(B) shows an example of a 45° diagonal screen, each of which is composed of a 3×3 matrix. By dividing one pixel into five fine pixels as described above, it can be said that the resolution in the X direction is increased. Furthermore, in the case of a 3×3 matrix, the number of gradations becomes 5×9+1=46 levels, which increases the gradation reproducibility.

Such multivalued data is directly output to a printer or stored in a memory (not shown). When storing to memory, as mentioned in the character output above, if each pixel indicates the state of Σ5Ci = 25 = 32, 5 bits/pixel are required, but in the case of a halftone image, halftone When outputting an image, as shown in the threshold matrix in Figure 8 (CB), the system uses a left-aligned system in which the five micropixels within one pixel sequentially emit light from the left side, so there are only six possible states, and fLog26. Therefore, in the case of a halftone image, 3 bits per pixel is sufficient.

Figure 9 (A) is an example of Figure 8 (B) in which the center position of the blackening is prevented from moving, and Figure 9 (B) is an example of thickening from ■ to ■ with the line ■ as the center. It shows. FIG. 10 shows the order in which fine pixels are discovered within one pixel (order of blackening), where (A) is a concentrated type and CB) is a distributed type. Figure 11 (
A) and CB) show the light energy distribution generated by laser beam scanning based on FIGS.

Compared to the concentrated type shown in Fig. 11 (A), the distributed type shown in Fig. 11 (B,) changes the intensity of light energy more (in the vertical axis direction of the figure).
It can be said that it is suitable for a recording method that has a large diameter and can be driven analog. In this embodiment, one pixel is divided into five parts, but the invention is not limited to this.

As explained below, according to the present invention, one pixel is divided into a plurality of elements and outputted for bit patterns such as character fonts and gradation image signals, thereby producing a gradation image. An image output method that enables high-quality reproduction and high-quality output of characters, line drawings, etc. has been obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of a high-resolution output according to an embodiment of the present invention. Figures 2 (A) to (C) are diagrams showing examples of fine pixel arrangement. Figure 3 is diagrams showing examples of character output. Figure 4 (A) to (E) are examples of pixel fleshing. FIG. 5 is a diagram for determining the center coordinates of diagonal line filling, and FIG. 6 is a flowchart showing the processing of this embodiment based on FIG. 5. FIG. 7 is a block diagram showing image signal processing using the systematic dither method. FIGS. 8 (A) and (B) are diagrams showing an example of a dither matrix. FIG. 9 (A) is a diagram showing an example of a dither matrix. , FIG. 9(B) is a diagram showing the thickness of the line according to FIG. 9(A), FIG. 10(A), CB) is a diagram showing the order in which fine pixels increase, FIG. 11(A), (B) is a diagram showing the relationship between fine pixels and light energy. In the figure, 10.37... fine pixel, 11... comparator, 12... output signal, 13... ROM, 14...
- Image signal, 30-34... Vertex, 35... Pixel matrix. Patent Applicant Canon Co., Ltd. Agent Patent Attorney Yasunori Otsuka Figure 3 Figure 1 Figure 4 (C) Figure 6

Claims (3)

[Claims] (1) An image output method that reproduces an image using a pixel matrix, in which the pixels of the pixel matrix are divided into m elements in the scanning line direction, and any element among the m elements is divided into one pixel. An image output method characterized by outputting. (2) The output elements can be output at any position within one pixel for character output, and are output sequentially from one direction for gradation images. An image output method according to claim 1. (3) For character/line drawing output, 1 depending on the slope of the line segment.
2. The image output method according to claim 1, wherein an element to be output within a pixel is determined, and for a gradation image, an element to be output is determined based on a dither method or a density pattern method.