JPS62279953A - Image information processor - Google Patents

Abstract

PURPOSE:To enable a good printing in the same size as an original image even when a resolution is different between an image information output means and a printing means, by converting the image information being outputted from the image information output means into the line density of the printing means by means of a line density converting means. CONSTITUTION:A line density converting means 53 converts the image data being outputted from a personal computor 42 to a resolution of a printer 11 according to a conversion rate being set at a line density conversion rate setting section 52 and outputs it. When the image data is fed from the personal computor 42, a CPU 43 discriminate the header of said image data, and if it is text data, a character generator 50 functions to convert the text data into the image data having 24-bits per height of single character, if it is graphic data, a graphic pattern generator 52 functions according to a conversion rate being set in the line density conversion rate setting section 52, and if it is bit image data, the line density converting section 53 functions to convert the bit image data into a line density matching with the resolution of the printer 11. They are stored in a page memory 49, then read out sequentially and fed to the printer 11.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Object of the Invention] (Field of Industrial Application) This invention provides image information with different linear densities output from an image information output means such as a personal computer. The present invention relates to an image information processing apparatus that converts an image to match the linear density of a printer device.

(Prior Art) As is well known, printers that can print image data such as graphics in addition to text are becoming popular.

Among these types of printers, those that have a high resolution (1! degrees) and can record on plain paper include electrophotographic printers that use a laser or light emitting diode (LED) as a light source,
There are thermal transfer printers, inkjet printers, etc. that use thermal heads.

The resolution of these printers is 200.24 depending on the model.
The resolution of one printer is usually fixed to one, although it varies from 0.300.400.480 dots/inch.

On the other hand, personal computers and word processors that output iiiIm data also have different output image resolutions depending on the device. For this reason, for example, if you use a printer with a higher resolution than the image information output device, not only will you not be able to take full advantage of the printer's performance, but you will also
In some systems, it was not even possible to connect a printer to an image information output device.

Therefore, in the past, printers connected to personal computers and word processors were designed to use a printer with a resolution that matched the resolution of the device to which it was connected, so multiple image information output devices with different resolutions were used. When used, a plurality of printers are required correspondingly, resulting in an inconvenience that the total cost increases.

(Problems to be Solved by the Invention) This invention solves problems such as the quality of printed books due to the difference in resolution between image information output devices and printers. It is an object of the present invention to provide an image information processing apparatus that can perform good printing at the same size (same size) as the original image even when the resolution of the printing means is different.

[Structure of the Invention] (Means for Solving the Problems) The present invention comprises: an image information output means for outputting image information at a predetermined linear density; a printing means for printing image information at a predetermined linear density; a setting means for setting a linear density conversion rate for the printing means of image information outputted from the image information outputting means; and a setting means for setting a linear density conversion rate for the printing means, and outputting from the image information outputting means based on the linear density conversion rate set by the setting means. and a linear density converting means for converting image information into a linear density suitable for the printing means.

(Function) This invention converts the image information output from the image information output means into the linear density of the printing means by the linear density converting means according to the linear density set by the setting means, so that the image information is identical to the original image. It is designed to form high-resolution images.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 6 shows a laser printer as a printing means applied to this invention. This printer 11 is a device using a semiconductor laser, and has 400 pixels in both main scanning and sub-scanning.
It has a w4III degree of dots/inch.

In the figure, a so-called polygon mirror 13 is provided inside the printer main body 12 to capture pulsed laser light emitted from a semiconductor laser (not shown) in the main scanning direction. This polygon mirror 13 is rotated by a motor 14.
The laser beam reflected by the first fθ lens 1
5, the photoreceptor drum 19 is irradiated through the mirrors 16 and 17 and the second fθ lens 18 in this order. This photosensitive drum 19 is configured to be rotated in the direction of the arrow shown in the figure.
First, the surface of the photoreceptor drum 19 is charged by the charger 20 . Thereafter, when the laser beam is irradiated, the charge on the surface of the photoreceptor drum 19 that is irradiated with the laser beam is removed, and an electrostatic latent image is formed. Can this electrostatic latent image be developed by the developing device 21? J! Become a statue. That is, the developing device 21 includes the photosensitive drum 19.
Toner charged to the same polarity as the surface of the photoreceptor drum 19 is stored, and this toner is adhered to the surface of the photoreceptor drum 19 by the developing roller 21a, thereby forming an electrostatic latent image.

On the other hand, a paper feed cassette 22 is provided at the bottom of the printer main body 12.
is removably provided, and the paper P stored in this paper feed cassette 22 is taken out by a paper feed roller 23 that is driven in synchronization with the rotation of the photosensitive drum 19. This taken out paper P is transferred to the aligning roller pair 24.
The leading end is aligned and sent to the transfer section 25. In the transfer section 25, the developed toner image is transferred onto the fed paper P by a transfer roller 25a charged to the opposite polarity to the surface of the photoreceptor drum 19. The paper P to which this toner image has been transferred is sent to a pair of fixing rollers (heat rollers) 26, and by passing therethrough, the toner image is fixed.

The fixed paper P is discharged by a pair of paper discharge rollers 27 to a paper discharge tray 28 provided on the upper surface of the printer main body 12.

Furthermore, after the transfer has been completed, the photosensitive drum 19 is returned to its initial state by erasing the afterimage by the discharge lamp 29.

Note that 30 is a cooling fan that cools the inside of the printer body 12, and 31 is a printer that controls each part of the printer 11 and controls a semiconductor laser (not shown) to blink in accordance with image data supplied from an external device. This is the control section.

FIG. 1 shows a linear density converter.

This linear density conversion device 41 converts the resolution of image data output from, for example, a personal computer (PC) 42 to the resolution of the printer 11 described above. The personal computer 42 outputs predetermined image data in a predetermined format, no matter what type of printer it is connected to.

FIG. 2 shows the format of image data output from this personal computer 42.
D is a header of the entire image data, GD is graphic data, TO is text data such as characters, and BD is bit image data.

These data GD, TD, and BD include a header HD1 consisting of information such as the data length of each data and the position on the printing paper.
HD2, HD3, and each of these headers H1gh, H
It is composed of image data DD1, DD2, and DD3 corresponding to the information indicated by D2NHD3. Among these, image data DD in bit image data BD
3 is 200 dots/inch in this embodiment.

On the other hand, in the linear density conversion device 41, a CPU 43 consisting of, for example, a microcomputer controls the entire device.
is connected. This system bus 44 includes a ROM
45 and RAM 46 are connected. These ROM45
, RAM 46 stores programs necessary for the operation of the CPU 43. Further, the personal computer 42 is connected to a system bus 44 via an interface (1/F) 47. Roughly speaking, between the system bus 44 and the image bus 48, a page memory 49, a character generator 50, a graphic pattern generator 51, a linear density conversion rate setting section 52, a linear density conversion section 53,
A printer interface 54 is connected. The page memory 49 stores the conversion output of a linear density converter, which will be described later, and has a storage capacity of, for example, 8 MB. The character generator 5o generates a font consisting of 24 bits per character height based on the image data of the personal computer 42. The graphic pattern generator 51 generates preset patterns based on image data supplied from the personal computer 42.

The linear density conversion rate setting unit 51 sets the conversion rate (b/a) between the resolution (a) of the personal computer 42 and the resolution (b) of the printer 11, and in this embodiment, for example, a switch , and memory. A plurality of conversion rates are stored in this memory, and when the switch is operated, the conversion rate (b/a) is outputted from the memory accordingly.

The linear density conversion units 5 to 3 convert the image data output from the personal computer 42 to the resolution of the printer 11 and output the image data according to the conversion rate set by the linear density conversion rate setting unit 52. This will be discussed in detail later.

Printer interface 54 connects image bus 48
The linear density-converted image data supplied from the page memory 49 is supplied to the printer 11 via the page memory 49.

In the above configuration, when image data is supplied from the personal computer 42, the cPU 43 determines the header of this image data. As a result, the input ii! When the i-image data is text data TD, the character generator 5o is operated to convert this input image data into the aforementioned image data of 24 bits per character height. This converted ii image data is stored in the page memory 49.

Also, the input image data is graphic data GD.
In this case, the graphic pattern generator 52 is operated according to the conversion rate set by the linear density conversion rate setting section 52, and graphic image data of a size matching the resolution of the printer 11 is generated. This generated image data is stored in page memory 49.

Roughly speaking, when the input image data is pit image data BD, the linear density converter 53 is operated according to the conversion rate set by the linear density conversion rate setting unit 52, and the bit image data is transferred to the printer 11. is converted to a linear density that matches the resolution of This converted image data is
The information is stored in the page memory 49.

Each image data converted to match the resolution of the printer 11 as described above is sequentially read out from the page memory 49 and supplied to the printer 11 via the image bus 48 and the printer interface 54. Therefore, the printer 11 to which this image data is supplied forms a high-resolution image that is the same size as the original image output from the personal computer 42 and that matches the resolution of the printer 11. Note that the output of the word processor 64 is also converted in the same manner.

According to the above embodiment, the linear density conversion device 41 converts the resolution of image data output from the personal computer 42 to match the resolution of the printer 11. Therefore, no matter what resolution an image information output device such as a personal computer has,
Since it can be printed at the same size as the image output from the image information output device, there is no need to prepare printers with various resolutions to match the resolution of the image information output device as in the past, reducing the total cost. is possible.

Furthermore, when the line density of the image information output device is lower than that of the printer 11, it is possible to process the image information at low cost and at high speed with a small amount of bits.
The images formed by this method have high resolution and therefore have good image quality.

Next, other embodiments of the invention will be described.

In FIGS. 3 and 4, the same parts as in FIG. 1 are denoted by the same reference numerals, and explanations thereof will be omitted.

FIG. 3 schematically shows the system configuration of this embodiment. The linear density conversion device 61 includes first and second personal computers 62, 63, and a word processor 6.
4. A scanner 65 that reads image data and outputs an electrical signal corresponding to the image data, and a communication control section 66 are connected.

This communication control unit 66 controls the facsimile G [[I, GI
Communication is possible using the V protocol, and this communication control unit 66 includes a communication line network 67 and a digital communication line network 6.
8 via G■, GIV facsimile 69.70.
71 is connected.

The resolutions of the various types mentioned above are as follows.

Personal computer 62.63... 200 dots/inch for both main and sub-scanning Word processor 64... 300 dots/inch for both main and sub-scanning Scanner 65... 400 dots/inch for both main and sub-scanning Printer 11...・400 dots/inch for both main and sub-scanning Facsimile 69.70 Main scanning: 8 lines/mm Sub-scanning: 7.7 lines/mm.

Or 3.85 lines/mm Facsimile 71... 200 dots/inch for both main and n1 scanning, or 24
0 dot/inch, 300 dot/inch, 400 dot/inch FIG. 4 shows the configuration of the linear density converter 61. The personal computer 62.63 and word processor 64 each have an interface 72.73.
, 74 to the system bus 44, and the communication control unit 66 is directly connected to the system bus 44. Further, a keyboard 80 is connected to the system bus 44, and a scanner 65 is connected via a scanner interface 75.

Further, between the system bus 44 and the image bus 48, a data hood expansion unit 76, a terminal l! A density determination section 77 and a terminal number determination section 78 are connected.

The data code decompression unit 76 is, for example, a facsimile 6
This is to decompress the compressed image data sent from 9.70 and 71.

The terminal number determination unit 78 determines whether the terminal currently sending image data is, for example, a personal computer 62, 63,
This is for identifying whether it is a word processor 64, a facsimile connected via the communication illumination unit 66, or a scanner 65.

Terminal 1a! The degree discrimination unit 77 is configured to determine whether the image data is
The IIWi degree is for determining one of the above-mentioned types, and, for example, as shown in FIG. When the terminal number is supplied from the unit 78, the linear density conversion rate corresponding to the number is output.

In the above configuration, the operation will be explained.

A personal computer 62 is connected to the linear density converter 61 .
63, word processor 64 or scanner 65,
When image data is input from a facsimile 69, 70, or 71, a terminal number determining section 78 determines from which terminal the image data was input, and the determination result is supplied to a terminal linear density determining section 77. Of this input image data, text data TD output from the personal computer 62, 63 and word processor 64
, graphic data GD, the resolution of the image data is converted by the character generator 50 and the graphic pattern generator 51, as in the embodiment described above. Regarding the bit image data BD, the linear density converter 53 is operated to convert the linear density according to the linear density conversion rate of the terminal determined by the terminal linear density determiner 77. This converted image data is stored in the page memory 49, and then supplied to the printer 11 via the printer interface 54 and printed.

Further, image data input from the scanner 65 is sent to the page memory 49 via the scanner interface 75.
is memorized. The resolution of the scanner 65 and the printer 11
Since the resolution of 49 is matched, this page memory 49
The 1M11 data stored in is directly supplied to the printer 11 via the printer interface 54 and printed.

On the other hand, the image data from the facsimiles 69, 70, 71 supplied via the communication control section 66 is first supplied to the data code decompression section 76 and decompressed. This expanded image data is supplied to the $1 density converter 53, and the linear density converter 53 performs linear density conversion according to the linear density conversion rate set by the terminal linear density determiner 77. be exposed. In this case, there are 6 and 7 fax machines in Gm mode.
Image data starting from 0 is converted in the main scanning direction and the sub-scanning direction. This converted Wijll data is stored in the page memory 49, and this page memory 4
The image data stored in 9 is supplied to printer 11 via printer interface 54 and printed.

According to the above embodiment, the terminal number determining unit 78 determines the terminal number outputting the image data, and the terminal linear density determining unit 77 sets the S density conversion rate according to the determination result. The linear density converter 53 performs the conversion. Therefore, even when a plurality of uniform information output devices with different resolutions are provided for one printer 11, the image data output from the image information output device is automatically adjusted to the linear density of the printer 11. Because it can be converted, it is extremely convenient in practice.

Further, since it is possible to connect a plurality of image output devices to the printer 11 that is used infrequently, the total cost can be reduced.

Furthermore, by using this linear density conversion device 61,
This can be transmitted to the high-resolution printer 11 from a low-resolution facsimile according to the G111 standard.

Next, the linear density converter 53 will be explained.

As this linear density converting section 53, Japanese Patent Application Laid-Open No. 56-9037
Although the image enlarging/reducing device disclosed in Japanese Patent No. 5 can be used, a circuit that is further improved from this device will be described here.

FIG. 7 shows an embodiment of the linear density converter 53.

The linear density conversion unit 53 includes a converted pixel position detection circuit 101 that detects the position of a converted pixel in an original image, an original pixel extraction circuit 102 that extracts a referenced original pixel, and a converted pixel position detection circuit 102 that extracts a referenced original pixel, and a converted pixel position detection circuit 102 that calculates the density of a converted pixel. A density calculation circuit 103, a threshold setting unit 104 that dynamically sets a threshold, a binarization circuit 105 that binarizes the converted image density, an input interface 106 that takes in image data, and an input interface 106 that takes in image data. The main part is composed of an output interface 107 that outputs the image data, and a control circuit 108 that controls input/output processing and conversion processing. It is composed of a system bus 12 for exchanging parameters and the like, and a control bus (not shown) connecting the control circuit 108 and other circuits.

Further, the original pixel extraction circuit 102 stores a line buffer of the maximum number of reference lines so that reference pixels can be easily selected. 102a, and a pixel extraction circuit 102b that accesses the line buffer y102a.

The threshold setting unit 104 also includes the original pixel density analysis circuit 1
04°a1 and a threshold selection circuit 104b.

Next, the specific configuration and operation of the main parts of this embodiment will be explained.

First, the converted pixel position detection circuit 101 will be explained.

Figures 8 and 9 show the positional relationship between the original pixel and the converted pixel in the original image during reduction conversion and enlargement conversion, respectively. It indicates the location.

Now, if the distance between original pixels is normalized to 1, the conversion rate r
is expressed as r-1/S (1), where S is the distance between the converted pixels in both figures. Also, the sampling position of the j-th converted pixel is i-[5-jl (where [] is a Gauss symbol)...from the position where the i-th original pixel that satisfies (2) is captured. It can be thought of as a position with a slight variation roughly t-8-J-i (0<t<1) (3).

From this, the converted pixel position detection circuit 101 detects the I! of the original pixel in synchronization with the transfer 4 of the original pixel. ! It is possible to configure it by a counter that indicates the Ij1 position, an arithmetic unit that updates the converted pixel position, and a comparator that compares both.

Therefore, as shown in FIG. 10, this original pixel position detection circuit 101 has a register 111 that stores the sampling interval S of the converted image, that is, an integer part of the linear density conversion rate, and a register 112 that stores the decimal part. , adders 113 and 114 that update the sampling position of the converted image, latches 115 and 116 that store the converted pixel position and are updated by the clock CP-CNV, and latches 115 and 116 that store the coordinate position of the original image and update the clock CP-CNV. - A counter 117 counted up by ORG, a comparator 118 that compares the converted pixel stored in the latch 115 and the counter 117 with the original pixel, and outputs a conversion operation request signal RQ-CNV when both match. The X-coordinate circuit has the same configuration as the X-coordinate circuit, and the Y-coordinate circuit has the same configuration. In addition, at the initial stage, the latches 115 and 116 and the counter 11
7 has been cleared.

First, in the case of reduction, since the latches 115 and 116 are both O at the initial stage, the conversion operation request signal RQ-CNV is output, and the conversion operation is performed. At this time, according to this conversion calculation request signal RQ-CNV, the clock CP-CNV
is input and the next converted pixel position is latched 115.116
is stored in Then, each time the original pixels are input sequentially,
The counter 117 is updated and the value of the latch 115 is again
When the values of this counter 117 match, the conversion calculation request signal RQ-CNV is output again. Also, at this time (
The minute displacement t shown in equation 3) is stored in the latch 116.

In addition, in the case of enlargement, since interpolation is performed between original pixels using a plurality of pixels, the conversion calculation request signal RQ-CN is always used.
V is output, but conversely, when the converted pixel position exceeds the original pixel position in the process of sequentially updating the stored latches 115 and 116, that is, the carry of the adder 114 is output as the original pixel capture request RQ. - By using it as an INP, position detection is processed sequentially. Note that the coordinate positions of the converted pixel and the original pixel are cleared each time the end of the line is reached.

Next, the original pixel extraction circuit 10.2 will be briefly explained.

FIG. 11 shows the configuration of the original pixel extraction circuit 102 of this embodiment. This original pixel extraction circuit 102 includes four line buffers 121 to 124 and a part (4×4
), and a multiplexer 126 that rotates this reference original pixel.

This original pixel extraction circuit 102 sequentially stores and shifts the original pixels of each row into line buffers 121 to 124 connected in series, extracts four pixels of each row into a register 125, and outputs a conversion operation request signal R- When receiving the CNV,
Multiplexer 12 to this 4x4 pixel ptt~I)44
6, the referenced original pixel data Ql
Output as t~Q44.

Furthermore, the rotation processing of this original pixel extraction circuit 102 will be explained. In this embodiment, the theoretical formula for the conversion calculation is a smoothing function with a positive weight distribution. In this case, the converted pixel Q1 is at a position as shown in FIG. 12(a), and Q! in the density distribution as shown in FIG. The calculated density value is the same as the calculated density value when the converted pixel Q2 is at a position as shown in FIG. 12(b) and the density distribution is as shown in the same figure. Therefore, in order to eliminate redundancy in calculations, in this embodiment, the original pixels are divided into four as shown in FIG. 13, and the reference original pixel is rotated depending on which of these four the converted pixel position belongs. All converted pixel positions are arranged in the second quadrant. Note that the minute displacement output from the converted pixel position detection circuit 1 may be referred to as to which divided region this converted pixel position belongs.

Next, as shown in FIG. 13, the converted pixel density calculation circuit 103 of this embodiment has four R
It is composed of OMs 131 to 134 and adders 135 to 137 that add their outputs. Also, this RO
By switching M131 to M134, several types of arithmetic expressions can be selected.

This converted pixel density calculation circuit 103 is the original pixel extraction circuit 1
With reference to the referenced original pixel information Q1t to q44 output from the pixel position detection circuit 101 and the minute displacement between the original pixels output from the pixel position detection circuit 101, the ROM 131 to 13 is stored for each 2×2 pixel.
Adders 135 to 137 sequentially add the matching density values within 4, and output the result as a multi-value.

Next, the original pixel density analysis circuit 104a of this embodiment will be explained. The main parts of the original pixel density analysis circuit 104a include an average density calculation device 140 that operates during reduction conversion, and a pattern detection circuit 150 that operates during enlargement conversion.

First, as shown in FIG. 14, this average density calculation circuit 140 operates from a ROM 14. -1, 142 and an adder 143 that adds these density values, and the threshold selection circuit 1
04b is connected to a ROM 161 in which a threshold value corresponding to this result is stored.

A method of setting a threshold value using this average density calculation circuit 140 will be explained.

Conventionally, when converting arithmetic results into binary values, even if the threshold value is constant or variable, one of the output results
This is a method in which the user resets the threshold value by looking at the i-image, and the threshold value cannot be locally changed depending on the partial characteristics of the image, and is a fixed method. In this method, as shown in Figure 15(a), if a threshold is set so that thick characters are reduced while preserving their shape,
As shown in the figure, the figure made up of thin lines becomes extremely thin and partially disappears. On the other hand, if the threshold value is set based on I'll, as shown in FIG. 15(b), blurring will occur in the thick line figure.

However, in this embodiment, we pay attention to the fact that the above-mentioned two shapes have greatly different densities per unit area, and calculate the average density from the reference pixel data, and then apply threshold correction based on the result. This eliminates the harmful effects of this constant threshold dipping method.

FIG. 16 shows the pattern detection circuit 150.

This pattern detection circuit 150 includes a ROM1 for specific detection.
51, and this ROM 151 is connected to a threshold selection ROM 162 of the threshold selection circuit 104b.

A method of setting a threshold value using this pattern detection circuit 150 will be explained.

In the case of enlargement conversion, if the converted pixel density value is simply replaced by the neighboring original pixel, the image quality will be greatly impaired as described above, but in particular, as shown in Figure 17, large jags will appear in the shaded area, making it very difficult to see. Become. This can be resolved to some extent by performing smoothing processing that calculates the density with reference to a plurality of neighboring original pixels, and by binarizing with a constant threshold.

However, in the case of a diagonal line consisting of a series of one point, the continuity of the diagonal line may be lost. For example, in the positional relationship shown in FIG. 18, the smoothing function of the converted pixel Q is set as follows.

However, Do indicates the density value of the pixel Q.

DQ -(1-u)(1-v)Op l J+LJ (
1-V) Op l J +1+ (1-u)VOp
l +l J uvDp I +I J +1 (0≦U, ■≦1) ... (4) At this time, when this result is binarized with a threshold of 0.5, the black single-point diagonal line is , as shown in FIG. 19(a). This is because the white region pixels in the figure greatly influence the determination of the density of the converted pixels, and in this case, if the threshold value is lowered, continuity can be maintained as shown in FIG. 19(b).

However, if other parts are also binarized using this threshold, the image quality will be greatly impaired, and, for example, a white diagonal line on a black background will be erased. .

On the other hand, it is desirable that the straight cross and key-shaped parts be enlarged while maintaining their original shapes.

However, as described above, this portion also has a rounded shape as shown in FIG. Now, if we use equation (4) as the smoothing function, we can increase the threshold value to 0.75 for the x1 part, and conversely set the threshold value to 0.25 for the x2 part, so that the shape of the hole can be changed. Saved.

In this way, by dynamically changing this threshold every time a specific pattern is detected, enlargement processing can be performed without changing the shape of the original image.

Furthermore, when detecting a specific pattern from a 4×4 pixel area, diagonal lines, key shapes, etc. have directions, which complicates the detection conditions. However, since the referenced original pixel data is rotated in the original pixel extraction circuit 102, the calculation of the converted pixel density value is limited to the second quadrant of the four-division part of the micro area between original pixels. . Furthermore, it is necessary to change the threshold value for the converted pixels of the region MW shown in FIG. 19 and the region [X shown in FIG. , the direction can be ignored.

That is, referring to FIG. 21, the pattern detection conditions for the reference pixels Q1t to Q44 after rotation are as follows.

(a) Black single point diagonal line detection Q22 = O and C23 = 1 and C32-1 and q33
-0 and <Qt 3-0 or Q24-0) and') (
C131-0 Mataha Q+ 2-0) (However, ○: white pixel, 1: black pixel) (b) White single point series diagonal line detection C22-1 and Q23 =O and Q32 =O and C3
3-1 and (Qt:+-1 or Q2+=1) and (C
31=1 or C42=1) (c) Black key shape detection Q22=O and C23-1 and Q32=1 and C33
=1 and (Qt3-1 or Q3t=1>(d) White key shape detection q22 1 and 023 0 and q32 =O and qyo3
−0 and (Qt3=O or C31−○) Thus, in this example, reference pixels q22, q23 after rotation
, Q32 , Q33 , Qt 3 .

This detection is performed by referring to only eight pixels C24, C31, and C42.

Furthermore, the threshold value set by the threshold selection circuit 104b connected to this pattern detection circuit 150 is
As shown in FIG. 22, when a black single-dot diagonal line is detected, it is 0.35; when a white single-dot diagonal line is detected, it is 0.65;
The value is 0.75 when a black key shape is detected, 0.25 when a white key shape is detected, and 0.5 in other cases.

cruelty Next, the operation of this linear density converter will be explained.

First, original image data to be subjected to linear density conversion is taken in by the input interface 106 via the image bus 48. In synchronization with the transfer of each pixel of the original image data, the converted pixel position detection circuit 101 executes conversion pixel position detection processing.

When the corresponding position of the converted pixel is detected, the pixel extraction circuit 102b extracts referenced original pixel data from the line buffer 102a in order to calculate the converted image density and analyze the surrounding density distribution state. The referenced original pixel data is input to the converted pixel density calculation circuit 103 and the original pixel density analysis circuit 104a.

Next, in this converted pixel density calculation circuit 103, the density calculation of the converted pixel is performed according to these referred pixel data and the position data of the converted pixel outputted from the converted pixel position detection circuit 101. Concentration analysis circuit 104a
Then, a peripheral average density calculation or a specific pattern detection process is executed, and a threshold value is set based on the result.

Based on this threshold value, the density value of the converted pixel is binarized.

This result is then output from the output interface 107 via the image bus 48.

Incidentally, FIGS. 23 and 24 show an example of an enlarged version of this embodiment.

In the figure, (a) is the original image, and (b) is the image converted using the shortest distance approximation method, and considerable jaggedness can be seen in the shaded area.

In the same figure (C), the conversion is performed using a certain threshold, and the cross and key-shaped parts become rounded.
The continuity of the dotted line shaded area is lost. Same figure (
d) is a conversion example according to this embodiment, in which all the above-mentioned drawbacks are eliminated.

As shown in FIG. 25, the threshold setting section 104 uses a large ROM 171 and has an average density calculation circuit 140,
Pattern detection circuit 1501 and threshold selection circuit 10
4b can be combined into one. In this case, as shown in FIG. 25, a very simple configuration can be achieved.

Further, in this example, the average density and specific pattern are detected with reference to a 4×4 pixel area, but the accuracy will be improved if this range is further expanded. This effect is particularly significant if the line density of the original pixels is high. However, since there are original images with low linear density, it is possible to respond more flexibly by changing this reference range arbitrarily, and high-quality linear density conversion is possible.

FIG. 26 shows the configuration of the threshold setting unit 104 that refers to a 4×4 to 8×8 pixel area.

This threshold setting unit 104 includes ROMs 181 to 184 for total density calculation in a 4×4 area and significant 16 of the reference pixels.
RO for specific pattern detection where pixels are selected and input
See M 185, adder 186 for average concentration calculation, multiplexer 187 for switching threshold setting based on surrounding average temperature or specific pattern, ROM 188 for threshold selection, and 4×4 area. The control line 189 includes a selection control line 189 that sends a signal indicating whether to set the threshold value or refer to an 8×8 area, and a control line 190 that sends a signal that switches whether to set the threshold value based on the average density or a specific pattern. .

In this threshold setting section 104, the reference area can be freely switched, and the original pixel density analysis circuit 104a and the threshold selection 104a are combined in a simple configuration.

Note that the configuration of the linear density converter 53 is not limited to the above embodiment, and can be modified in various ways.

Further, although the linear density converter M41.61 is provided separately from the printer 11, the present invention is not limited thereto, and it may be built into the printer 11.

It goes without saying that various other modifications can be made without departing from the gist of the invention.

[Effects of the Invention] As described above in detail, according to the present invention, the linear density conversion means converts the image information output from the image information output means into the printing means according to the linear density set by the setting means. Since the image information is converted to a linear density of It is possible to provide a capable image information processing device.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is a circuit configuration diagram showing a linear density converter, FIG. 2 is a diagram for explaining the format of input data, and FIGS. The figures are shown to explain other embodiments of the present invention, and FIG. 3 is a system configuration diagram, FIG. 4 is a circuit configuration diagram showing a linear density converter, and FIG. 5 is a terminal linear density discrimination diagram. FIG. 6 is a side sectional view showing a printer device to which the present invention is applied, FIG. 7 is a configuration diagram showing an embodiment of the linear density converting section, and FIGS. 8 and 9 are respectively Figures shown to explain the operating principle of the converted pixel position detection circuit, Figure 10 is a circuit configuration diagram showing the pixel position detection circuit, the 11th cause is a configuration diagram showing the original pixel extraction circuit, and Figure 12 is the original pixel extraction circuit. Diagrams shown to explain the operation of the circuit, FIG. 13 is a block diagram showing the converted pixel density calculation circuit, FIG. 14 is a block diagram showing the average density calculation circuit, and FIG. 15 is a threshold value by the average density calculation circuit. FIG. 16 is a block diagram showing the pattern detection circuit, FIGS. 17 to 21 are diagrams shown to explain the operation of the pattern detection circuit, and FIG. 22 is a diagram showing the configuration of the pattern detection circuit. Figures 23 and 24 are diagrams showing the threshold values set in the threshold selection circuit, Figures 23 and 24 are diagrams shown to explain the operation of the linear density converter, Figures 25 and 26 are the threshold settings, respectively. FIG. 7 is a circuit diagram showing a modification of the section. DESCRIPTION OF SYMBOLS 11... Printer device, 41. 61... Linear density conversion device, 52... Linear density conversion rate setting section, 53... Linear density conversion section, 66... Communication control section, 77... Terminal linear density determination unit, 78...Terminal number determination unit. Applicant's agent Patent attorney Takehiko Suzue Figure 1 HD Figure 2 @ Figure 3 Figure 4 Figure 5 Figure 1z Figure 7 0 Original pixel Figure 8 × Converted pixel OOOO Meng-5-x x x x x XX XXX X xxxxxx ×××××× ○ OOO Figure 9 (b) Figure 12 Figure 14 (a) (b) Figure 16 Figure 18 Threshold “”
L key i [s+o, ss (α) (b) Fig. 19 (a) (b) Fig. 20 Fig. 21 Fig. 23 (a) (b) (c) (d) Fig. 24
figure

Claims (5)

[Claims] (1) An image information output means for outputting image information at a predetermined linear density, a printing means for printing image information at a predetermined linear density, and a line for the image information output from the image information output means for the printing means. A setting means for setting a density conversion rate, and image information output from the image information output means based on the linear density conversion rate set by the setting means,
An image information processing device comprising a linear density converting means for converting the linear density into a linear density suitable for a printing means. (2) The image information processing apparatus according to claim 1, wherein the image information output means includes a plurality of image information output means, and each image information output means outputs image information with a different linear density. (3) A plurality of linear density conversion rates are set in the setting means, and the linear density conversion rates are switched by a switch means according to the linear density of the image information output means. The image information processing device described in . (4) A plurality of linear density conversion rates are set in the setting means, and the linear density conversion rate is automatically switched depending on the terminal to which the image information output means is connected. The image information processing device according to item 1. (5) The image information processing apparatus according to claim 1, wherein the printing means comprises a laser printer.