JPS60145767A - Picture recording system - Google Patents

Abstract

PURPOSE:To record a halftone picture including line drawing at high reproducibility by making halftone recording of both line drawing part and continuous drawing part by different intermediate modulating systems. CONSTITUTION:When a controlling section 6 outputs a line select signal to a picture data memory section 1 and sends a reading signal phis once, watched picture elements and peripheral picture element data are stored in shift register 11-13 of a line drawing detecting section 2. Subtracting circuits 14-17 calculate difference between picture data of each peripheral picture element and watched picture element, i.e. density, gradient. Comparators 18-21 compare the density gradient data with a reference value, and decides whether inputted data is line drawing or continuous drawing. When the result of decision of the line drawing detecting section 2 is continuous drawing, the halftone modulating section 3 makes halftone modulation by density pattern dither process. In the case of line drawing, halftone modulation is made only by binary density pattern of small matrix.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an image recording system, and more particularly to an image recording system that enables images including line drawings and continuous drawings to be recorded with good reproducibility.

2. Description of the Related Art There is a method called a dither method as a method for reproducing an image with gradation at a binary level. This method, for example,
As shown in the figure, 1 pixel (1, 1), (1, 2).

... are arranged on a plane, 2X2, 3Xj, 4 as shown in FIG.
The threshold value 71 helix 'I'' (k, Q) consisting of (1,1
) and the size of the threshold matrix ゛J'(1,1) above, and set the pixel 01 (1,1) of S(1,I)>T(1,I) to ``BI'' (black). , conversely, S
This is a method in which the 61st pixel (1,1) of T(+,l) (1,]) is set to "0" (white).

Conventionally, in the recording method of an image including a line drawing and a continuous sub-side, as disclosed in Japanese Patent Application Laid-Open No. 57-203184, the dither method and the normal binarization method are used.
I was trying to use it instead.

However, in such an image recording method, line drawings are expressed in binary values, so a fundamental problem arises in that natural line drawings cannot be reproduced.

Purpose The present invention has been made in view of the above circumstances, and its purpose is to solve the above-mentioned problems in conventional recording methods, and to record both line drawings and continuous sub-sides with good reproducibility. The object of the present invention is to provide an image recording method that enables the recording of images.

Configuration Hereinafter, the configuration of the present invention will be explained in detail based on examples.

FIG. 3 is a block diagram showing the overall configuration of an image recording apparatus showing an embodiment of the present invention. In the figure, ■ is an image data memory section that stores image data, 2 is a line drawing detection section which will be described later, and 3 is halftone modulation whose halftone modulation method can be changed by a control signal from the line drawing detection section 2. Part, 4
5 is a line buffer that stores halftone modulated recording data, 5 is a recording system such as a printer, and G is a basic timing signal, control signal, etc. for each part mentioned above.
The control section to be introduced is shown.

FIG. 4 shows the detailed configuration of the line drawing detection section 2. As shown in FIG. In the figure, 11 to 13 are shift 1 registers that store image data of the pixel of interest and surrounding pixels.

14 to 17 are the input differences of the 92 systems (+uT=lx
N ] -1N 2 + subtraction circuit, 18~
21 is a comparison circuit that compares the human power of two systems, 2
2 indicates an OR circuit.

The operation of the line drawing detection section 2 configured as described above will be explained below.

The control section 6 stores the line sereno 1 in the image data memory section 1.
When the - signal is output and the read signal φ is sent once, the image data (here, 5 bits) of the pixel of interest and surrounding pixels are stored in the shift register 1-13. That is, the image data of the target image 4 is stored in the center of the Shift 1 register 2, and the image data of the surrounding 4 pixels are stored on the left and right sides of the Shift 1 register 2 and the right side of the Shift I register 1.13.

The subtraction circuits 14 to 17 at the next stage calculate the difference between the image data of each peripheral pixel and the "Note 1" pixel.

This difference indicates the concentration gradient in each pair. Then, in the next stage of comparisons w118 to w118 to w21, the concentration gradient data and threshold data are compared, and if the concentration gradient>threshold data, II1'' is set, otherwise, C is set to "0". Each is output.

Since the four output signals of 2J and Shira are input to the OR circuit 22, if at least one pair of density gradients exceeds a certain threshold, it is determined that it is a line drawing, and
l is output, and if not, it is determined that the sub-side is continuous and '0' is output.

Next, the halftone modulation section 3 will be explained.

FIG. 5 shows the detailed configuration of the halftone modulation section 3. In the single halftone modulation section 3, in the case of continuous sub-side, it is a binary density pattern of 2 x 2 small 71-lix, and the small 71 to lix are divided into units of 2 x 2 large 71-lix (in this case, In the case of line drawings, halftone modulation is performed using only the binary sensitivity pattern of the above-mentioned 2x2 small matrix.

The halftone modulation section 3 combines the position information from the control section 6 and the both edge data from the line drawing detection section 2 into six addresses, and performs two systems of halftone modulation: modulation data for line drawings and modulation data for continuous tone drawings. Table memory 31 that outputs data. and a multiplex section 32 that selects the line drawing modulation data or the continuous drawing modulation data based on the line drawing detection signal from the line drawing detection section 2.

φ8 is a cross that is synchronized with dot recording in the main scanning direction, and is connected to the shift cross terminal of the line buffer 4 in the subsequent stage.
t+ connected. The clock (φ8) of φH/2 is supplied to the line drawing detection section 2 as a read signal and is at 1b.

φヮ is a clock synchronized with recording of one line, and φH
Two bits of parallel output sound from the /4 and φv/4 counters are input to the address section of the table memory 31 as position information. Continuous tone image modulation (density pattern + dither) is performed by storing table memory data corresponding to the address of the table memory 31, that is, halftone modulation data.

It is possible to configure both line drawing modulation (density pattern only) to be output simultaneously. The above two systems of modulation regulators are
It is configured to be switched in response to a line drawing detection signal from the line drawing detection section 2.

According to this embodiment, line drawings can also be expressed in halftones, so not only can more natural line drawings be expressed, but also line drawings can be made more natural by changing the threshold data input to the comparison circuits 18 to 21. Another advantage is that the operator can freely adjust whether to emphasize quality or continuous tone quality. Furthermore, when detecting line drawings, one judgment is made based on at least 1 density gradients in the main scanning and sub-scanning directions, so there is an advantage that detection accuracy is high for line drawings not only in the vertical and horizontal directions but also in diagonal directions. .

In the above embodiment, an example was shown in which halftone modulation based on a binary density pattern method was applied to each pixel; however, the present invention should not be limited to this; It goes without saying that halftone modulation based on a multilevel density pattern method may be applied. In this case, since the output of the table memory 31 shown in FIG. 5 is sent to a plurality of pins 1, a parallel/serial conversion circuit is required at the next stage of the line buffer 4.

Effects As described above, according to the present invention, both the line drawing part and the continuous tone part are recorded with different halftone modulation methods, so that halftone images including line drawings can be It is important to record both line drawings and continuous tone parts with good reproducibility.
This has the remarkable effect of increasing the ability of the user to perform.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the arrangement of pixel position coordinates, FIG. 2 is a diagram showing the arrangement of threshold matrices, FIG. 3 is a block diagram showing the configuration of an image recording device according to an embodiment of the present invention, and FIG. figure,
FIG. 5 is a detailed block diagram showing the main parts thereof. 1: Image data memory section, 2: Line detection section, 3: Halftone modulation section, 4 line buffer, 5: Recording system. 6: Control unit, 11-13: shift 1-register, 14-
17: Multiplication circuit; 18 to 21: Comparison circuit; 22: OR circuit; 31: Table memory i; 32: Multiplex section. Figure 1 Figure 2 (a) (b) (c) k-k-me Figure 3 1 3 4 5 Cow drawing image data

Claims (4)

[Claims] (1) In an image recording system that includes line drawings and continuous drawings, a means is provided to determine whether one pixel is in a line drawing part or in both continuous tone parts, and in the case of a line drawing part and in both continuous tone parts. An image recording method characterized by recording both halftones by changing the halftone modulation method. (2) If the determination method by the determination means determines the concentration gradients of the pixel of interest and at least four surrounding pixels, at least one pair of concentration gradients is equal to or greater than a predetermined reference value,
The image recording method according to claim 1, wherein the method determines that the image is a line drawing portion. (3) For continuous printing, the above-mentioned halftone modulation method performs halftone modulation using a large 71-rinse method using a density pattern dither method, in which each pixel is expressed in multiple values using a small 71-lix method using a binary density pattern method. 2. The image recording method according to claim 1, wherein for line drawings, each pixel is halftone modulated using only a small matrix based on a binary density pattern. (4) For continuous drawing, the halftone modulation method performs halftone modulation using a large matrix using a density pattern dither method in which each pixel is expressed in multiple values using a small 71-lix using a multivalue density pattern method. 2. The image recording method according to claim 1, wherein each pixel is subjected to halftone modulation using a multi-value density pattern only by rinsing.