JPS62257277A - Variable power processor for image data - Google Patents

Abstract

PURPOSE:To reduce the deterioration of a picture due to variable power processing by excuting the MTF correcction operation in the main scanning direction corresponding to the designated magnification in the main scanning direction and that in the main scanning direction corresponding to the designated magnification in the subscanning direction indepnedently each other. CONSTITUTION:An original image data read by a scanner SCR is applied with a variable power processing and MTF-correction in the main scanning idrection X by a variable power processor consisting of a latch 25, a data distributor 26, RAMs 1 and 2, a data selector 27, a main scanning direction variable power calculator 28, a microprocessor 35, a RAM 3 and sampling circuits 64 and 65 through a shading corrcetion circuit 24. Thereafter the original image data is applied with a variable power processing and MTF-correction in the subscanning direction Y by a subscanning variable power computing element 29. For the MTF correction, correction coefficients corresponding to magnificatione are set beforehand, and the MTF correction is applied by specify ing one of the coefficient with the magnifications. A variable power image data goes through a binarization circuit 30 or a gradation processor 31 and is ouputted to a printer PRT.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an image data scaling processing device used in a digital copier, facsimile, or other image processing device.

■Prior Art FIG. 8 shows the appearance of one of the conventional image reading devices. This image reading device has a shape similar to that of a copying machine with the top section cut off. A document is placed on a contact glass 2 and pressed by a document pressing plate 3. The operation unit 4 is equipped with several types of keys, such as a reading start button and a density selection key, and several types of displays that display setting statuses, operating statuses, etc., so that settings for various functions can be made. .

Start reading by pressing the start button 1
An image signal can be obtained.

9 and 10 show a typical configuration of the image reading device shown in FIG. 8, particularly the reading optical system, and FIG.
The figure shows the optical system when using a contact image sensor.
FIG. 1O shows an optical system when a reduced image sensor is used. In addition, there are other systems in which the document moves and the optical system is fixed.

When using a contact type image sensor as shown in FIG. 9, the optical system becomes a same-magnification optical system. The document surface on the contact glass 2 is illuminated by the fluorescent lamp 5, and the reflected light 8 is
It passes through the self-hock lens 6 and enters the image sensor 7.

The image sensor 7 detects the document width (in the depth direction in FIG. 9,
That is, one line of image data in the width direction having a width equal to or larger than the main scanning direction (X) is read at one time.

Number of sampling lines and sampling pitch P
The number of pixels in the image sensor determines the number of pixels. After reading the data for one line, the carriage 9, which includes the fluorescent lamp 5, self-hook lens 6, and image sensor 7, is driven in the direction of the arrow (sub-scanning direction Y), and the next line is read. Note that there is also a mode in which the carriage 9 is continuously driven in the sub-scanning direction Y. The pitch py between the lines is determined by the speed of the carriage 9, the charge accumulation time of the sensor 7, etc.1, but is usually set to be the same as the sampling pitch py described above.

When a reduced type image sensor is used as shown in FIG. 1O, the document width of the optical image is reduced by the lens 14 so that it matches the size of the image sensor. Although three mirrors are used in FIG. 10, a two-mirror configuration or a five-mirror configuration may also be considered.

Reading in the main scanning direction X is the same as when using a contact type sensor. l1llll scanning direction Y
In this case, a first carriage in which the fluorescent lamp 10 and the first mirror 11 are integrated, and a second carriage in which the mirrors 12 and 13 are integrated, each independently move the document from the contact glass plate 2 to the lens 14. It is driven so that the optical path length is constant.

Here, in the conventional variable magnification method, in the main scanning direction
This is done by changing the optical path length of the optical system to change the reduction ratio, and I! One scan is performed by changing the speed of the moving body in the scanning direction.

However, this method cannot be adopted when using a contact type sensor as shown in FIG.

In addition, even in the case of the reduced type sensor shown in Figure 1O, the range of magnification is structurally limited, such as the magnification does not change much despite the large amount of movement to change the order of the lens 14 and sensor 7. , and lens 14. A precise mechanism must be used for the movement accuracy and position adjustment mechanism of the sensor 7.

The coarse mechanism had major problems such as deformation of the read image.

Considering these conventional problems, recently, instead of optical magnification, data after magnification is pre-prepared from 1-1 magnification read data.
Image processing that calculates ltq and obtains variable-magnification image data, so-called electrical variable magnification, has come to be used.

However, the currently proposed electrical variable magnification has problems with the accuracy of variable magnification, and it is difficult to achieve accurate variable magnification.

There was a problem that the hardware became complicated and it became difficult to support so-called "Zoo 11" variable magnification such as in 1% increments or a wide range of variable magnification ratios.

Furthermore, when one image is read with a scanner, the spatial frequency characteristics of the image represented by the read data change, causing the image to deteriorate. Therefore, in the past, the read image data was lowered by 1 (Mo) at the required stage.
duration Transfer FuncF+i
on) Performs correction (roughly, restoration of blurred images). For example, a coefficient pattern (filter) is determined as shown in FIG. 13a, and target pixel data 0ik (here, data indicating density) is determined, for example, as shown in FIG. 13b.

Mik"■・Oi-1k+V・0ik-1+W・Oik
+1 +Z・Oi, 1 k+X−oik data M
Correct to ik. The correction coefficient V-Z<filter coefficient) is set to a value as shown in FIG. 14b, for example. Since these correction coefficients have appropriate values corresponding to the spatial frequency characteristics (sampling density) of the original image data, they are usually set to values corresponding to the original image sampling density of the scanner.

Therefore, the appropriate MTF correction characteristic will be different for a new sampling frequency at the time of scaling (the sampling link density of the scaling image data corresponding to one image of the original image), and it is necessary to change the correction coefficient. In particular, it is difficult to apply the correction coefficient (FIG. 14b) at the same magnification to a wide range of magnification from 50 to 400% as in the embodiment of the present invention described later.

If you ignore this and perform MTF correction at the reduction magnification or expansion magnification using the same correction coefficient (Figure 14b), the MTF will
Image blur due to over-emphasis of image etch due to correction! !
I+ phenomenon (striped pattern) occurs. Also, when changing magnification with different magnifications in the main scanning direction and sub-scanning direction, the optimal MTF correction coefficient is different for each direction, so it is not possible to obtain an appropriate MTF correction by only performing one type of MTF correction. I can't get the value.

■Purpose The present invention scales image data with relatively high precision, a relatively fine scaling ratio, and a relatively wide range of scaling ratios,
It is also an object of the present invention to prevent incompatibility of MTF correction, and further to perform appropriate MTF correction even when the magnification ratios in the main scanning direction and the sub-scanning direction are different.

First, the basic idea of variable magnification executed in the later-described embodiments of the present invention will be explained.

For example, image reading 'A' shown in FIG. 9 or FIG.
For the image data obtained at position A (hereinafter referred to as original image data), if the number of pixels in the main scanning direction It can be thought of as shown in Figure 11. In Fig. 11, when the magnification is changed in the main scanning direction at a magnification of R%, [N x R/100
One piece of new data (hereinafter referred to as variable-magnification image data) is created.

Here, three typical scaling algorithm methods will be described. Here, since the electric magnification is changed only in the main scanning direction, the following explanation will also be made in that direction.

First, in any method, it is necessary to recognize the position of the new sampling point after scaling, and to obtain the original image data of the old sampling points of several pixels surrounding the new sampling point -9- and their distances.

As shown in FIG. 12, the new spring boiling point is between S1j and Sij++ of the original image data, and -
9- is assumed to be rl and r2, and the sampling pitch of the original image data is assumed to be P.

■Nearest pixel replacement method This is a method that mainly sets the original image data at the closest position as the scaled image data of the vertical point. = S ij + 1. That is.

The image data of the sampling point of the original image closest to the sampling point -9- of the scaled image is set as the scaled image data Oik of the point -9-. Oik here is data indicating concentration.

(2) Adjacent Pixel Distance Linear Allocation Method This is a method of allocating density levels according to the distance between adjacent pixels of original image data. In Figure 12, the variable magnification image data O
ik is 0ik=(1-r1/P)Sij+(1-r2/
P) Sij+t'' (1).

03-order function convolution method Interpolation calculations are performed using an interpolation function h(γ) as shown in FIG.

h(γ) is approximated as shown in the following formula for γ which is cursed at sampling pitch P.

1-21γ12+1γbi O≦1γ1≦1h(γ)
=/l-81γl”+51γ12-1γ13 l≦
1γ1≦202≦1γ1 (2) Using this h(γ), the variable-magnification image data O1j is 0ik
= (h(1+r+ /P)Sij-1+h(rt/
P) Sij+h(r2/I')Sij+ + +h(1
+r2/P)Sij+2)/(h(1+rt/P)+
h(r+ /P)+h(r2/P)+h(1+r2/P
)] ”・(3>In addition to the above ■, ■, ■,
There are methods such as the adjacent pixel distance inverse proportion method and the adjacent pixel area allocation method, but since they are relatively similar to ■, here we will use the method described above.
,■.

Consider ■ as a representative example.

All of these methods have been known for a relatively long time and were mainly put into practical use in the field of computer image processing.

In cases such as computer image processing, where image data is stored in a high-capacity memory such as a single-page memory and then subjected to scaling processing, these methods can be used simply, but they do not have a single-page memory and require dedicated hardware. To perform these operations,
There are various restrictions.

When scaling is performed when reading with a digital copier, facsimile, etc., it is necessary to perform raster scanning (line by line) on data input in raster scanning (line by line) even after scaling processing. pixel synchronization pulse) must be constant at any magnification.

~ In other words, the data after the scaling process must be in the same format and at the same speed as the optical scaling process, that is, real-time processing is required.

This means that if variable magnification is considered for the digital copier system or facsimile system as a whole,
It's going to be different.

For example, if you can change the printing speed of a printer when changing the size, you can also change the data clock after changing the size. Furthermore, in a system that performs transmission, the raster scan data does not need to be after scaling.

However, when considering scaling as a reading device or as an independent scaling process, the raster scanning processing is limited as described above.

The embodiments of the present invention described below are magnification changers applicable to reading devices subject to these limitations.

FIGS. 6 and 7 are examples of time charts of data before scaling and data after scaling that satisfy this restriction. In these, LS'/NC is a horizontal periodic signal (line synchronization pulse: sub-scanning synchronization pulse), and one line of image data in the main scanning direction is read during one period of this signal. DCLK
is a data clock (pixel synchronization pulse). At the timing shown in FIG. 6, the pre-scaling data (in pixel units) Y is
Within the cycle of LSI/NC, up to 5i (1”SiN, D
It is assumed that the image is input to the scaling processing section in synchronization with CLK.

As a result, the scaled data Z is output, and although the output may be delayed from the data Y, it must always be synchronized with [) CLK. Also, the delay time (t2-tl)
is not particularly restricted, but must not change between lines,
t2 and tl must always remain constant.

Also, when inputting and outputting data in line units, the seventh
As shown in the figure, line buffer memories RAMI, RAM2
Read data (input) may lag behind write data (output).

Anyway, the most important and most difficult thing is to synchronize the scaled image data to DCLK at any scale.

Such a request can be achieved relatively easily if the magnification is variable with several types of fixed magnification, but especially with recent copying systems11
etc., a wide range of magnification is required, as well as small magnification changes of about 1% called zoom magnification, and it has become necessary for digital copiers, facsimiles, etc. to meet these demands. Therefore, in actually applying the above-mentioned magnification changing method, it is difficult to satisfy the above requirements.

(2) Configuration The variable magnification processing device of the present invention is compatible with a specified magnification Rx in the main scanning direction. A first calculation means for calculating original image data sampling position information for creating variable-magnification image data; corresponds to a specified magnification Ry in the sub-scanning direction. A second calculation means for calculating original image data sampling position information for creating variable-magnification image data: A designated sampling position of the original image data based on the original image data sampling position information calculated by the first calculation means! First sampling position specifying means for specifying x; Sampling specified position of the original image data based on the original image data sampling position information calculated by the second calculation means! a second sampling position specifying means for specifying rly; a first sampling means for extracting the original image data at the specified position X; a second sampling means for extracting the original image data at the specified position y; First variable scale image data setting means for determining variable scale image data corresponding to the original image data; Second variable scale image data setting means for determining variable scale image data corresponding to the original image data extracted by the second sampling means; A main scanning direction MTF correction means that has main scanning direction MTF correction calculation data associated with a setting range of magnification RX and performs MTF correction on image data after or before scaling in the main scanning direction based on the data; , has main-scanning direction MTF correction calculation data associated with the setting range of the specified magnification Ry, and performs MTF correction on the image data after or before scaling in the sub-scanning direction based on this data. A sub-scanning direction MTF correction means is provided.

According to this, the MTF correction calculation in the main scanning direction according to the designated magnification Rx in the main scanning direction and the designated magnification *Ry in the sub-scanning direction are performed.
Since the MTF correction calculation in the main scanning direction according to the Deterioration is reduced.

In the embodiment of the present invention, in order to execute real-time processing as described above, the first calculation means calculates 1001/(designated magnification Rx (%))=Ji+Ri, where i is an integer.

0≦Ri (1, Ji is an integer, the integer Ji and the decimal R
i is calculated by the first sampling position designation means.

Change i by 1 in synchronization with the data clock that determines the pixel unit of the original image data, and if R<100, set the specified sampling position x of the original image data to a number larger by 2 with Ji-Ji-1=2. , Ji-Ji-1=1 specifies the specified position X as a number larger by 1, and if R≧100,
Ji Ji-1 = 1, and the place fllx is increased by 1,
With JiJi-1=0, position a first variable-magnification image data setting means, in synchronization with the data clock, variable-magnification of the position i based on the correlation between Ri, the original image data of the designated position x, and one or more original image data adjacent thereto; Define image data.

According to this, the first calculating means and the first sampling position specifying means specify the sampling position Hz of the original image data at a pitch corresponding to the zooming percentage of 1% RX in the main scanning direction, and the first sampling means extracts the original image data at the number position 1i1x and the position adjacent thereto, and the first variable scale image data setting means executes a predetermined logic, for example, the above-mentioned
Set variable-magnification image data using processes such as ① and ②. The first sampling position designating means, the first sampling means, and the first scaling image data setting means all operate in synchronization with the data clock DCLK of the original image data.
The variable-magnification image data is synchronized with the data clock DCLK. That is, variable-magnification image data can be obtained through real-time processing. Therefore, scaled image data can be processed in a rask-scan manner.

The first calculation means increases i by 1 every time one pulse of the data clock DCLK appears, and calculates Ji and Ri.
It is also possible to calculate i before the actual image reading.
Calculate Ji and R1 for each of =0 to Rx-1 in advance, store these data in a memory such as RAM3, and synchronize with the data clock DCLK.
Sequentially, i may be changed to a number larger by 1 and Ji and R1 associated with that number may be read out. In any case, Ji and Ri may be sequentially changed in synchronization with the data clock DCLK. will be specified.

As described above, in the first calculation means, 100i/(designated magnification Rx (%))=Ji+RL i is an integer, 0≦Ri
<l.

Ji is an integer, and the maximum integer Ji is calculated in the form of an integer Ji and a decimal Ri, and based on this Ji and the previously calculated integer Ji, Ji-z, the first sampling position specifying means selects the original image. Data sampling position I
Since E'f x (ie, Ji) is specified, the scaling factor Rx (%) can be set to any number and range with 1 as the minimum unit. That is, a zoom magnification of 1% can be achieved, and the range of magnification can be set extremely wide.

In the embodiment of the present invention to be described later, the settable range is from Rx=50% to 400%, where the magnification change ratio is set in units of 1%.

a second calculation means that calculates sampling position information in the sub-scanning direction based on the specified magnification value Ry in the sub-scanning direction using the same processing logic as the processing element in the main-scanning direction described above;
second sampling position designating means for designating a designated sampling position y;

It is equipped with a second sampling means for extracting the data of the specified value tidy, and converts the data clock CLK in the explanation of the processing in the main scanning direction to the line clock LSYN.
Extract the data by replacing it with C.

In one embodiment of the present invention, a memory means for storing l lines of original image data; a means for alternately setting the memory means for writing/reading; a means for giving an address number 1 to a writing/reading position X to the memory means; : Equipped with. That is, it includes a line buffer memory.

The first sampling position specifying means applies a data clock 1) CLK that defines the pixel unit of the original image data to the address counting means when writing to the memory means, and when reading from the memory means. changes i by 1 for every pulse of data clock DCLK.
In addition to using a large number, if Rx<100, Ji-
When Ji-1=2, the count pulse 2DCLK with twice the frequency of the data clock DCLK is set to Ji-Ji-1=1.
, the data clock DCLK is applied to the address counting means as a count pulse, and if Rx≧100, J
When i-Ji-1 = 1, the data clock DCLK is applied to the address counting means, and when Ji-Ji-t = O, the count pulse to the address counting means is cut off to designate the read position X of the original image data. do. Prior to reading the original image, the first calculation means calculates 100i/(specified magnification Rx (%)) = J i + Ri, i = 0 to R
x-1゜0≦Ri < l t J x is an integer, data for specifying X corresponding to integer Ji and decimal Ri (Ai)
and data (Bi) for calculating the variable magnification image data and store them in the RAM3. When image reading is started, data is read from the RAM 3 using i as an address, and is provided to the sampling position designating means and the variable-magnification image data setting means. The variable magnification image data setting means is as described above.
In synchronization with the data clock DCLK, Ri (data Bi), 3 of the original image data at the designated position x read out from the memory means and one or more original image data adjacent thereto;
The correlation between people is r! This is assumed to be variable-magnification image data setting means for determining variable-magnification image data of 1i.

That is, in this embodiment, one line of original image data is stored in a buffer memory, and the reading address of the original image data is controlled to read and sample the original image data.
Obtain variable-magnification image data. The amount of change in the read address of the image data during reduction, that is, the read pitch of the original image data corresponding to the scaling factor, is determined by changing the count clock given to the read address counter of the buffer memory to the data clock DCLK and a frequency twice that of the data clock DCLK. clock 2DCLK
This is done by switching.

In another embodiment of the present invention, a line buffer memory is provided as in the previous embodiment, but the readout 71-res is performed by address counting means; up/down counting means; and count data of the address counting means and amplifier down. A count I of the counting means is set by an addition means for supplying the sum of the data to the line buffer memory as address data.

The sampling position specifying means supplies the data clock DCLK, which determines the pixel unit of the original image data, to the address counting means as a pulse from 1 to Rx when writing to the memory means, and when reading from the memory means, it supplies the data clock DCLK that determines the pixel unit of the original image data to the address counting means. If <100, the up/down count means is instructed to up, the data clock DCLK is given as a count pulse to the address count means, and the Ji-J
When i-1=2, the data clock DCLK is also applied to the up-down counting means, and when Ji-Ji-1=l, no clock pulse is applied to the up-down counting means, and Rx
If ≧100, the up/down count means is instructed to down and the data clock DCL is sent to the address count means.
K is given, and when Ji-Ji-1=1, the data clock DCLK is not given to the up/down count means.

When Ji-Ji-1=Q, it is assumed that the data clock D C1,K is also applied to the up/down count means to designate the reading position X of the original image data.

That is, the reading position X of the line buffer memory is determined by increasing or decreasing the number of data clocks DCLK according to the scaling factor.

Similar to the above setting of the read position (!1x), the read position Fly in the sub-scanning direction is also set.

Other objects and features of the invention will become apparent from the following description of an embodiment with reference to one drawing.

Fig. 1a shows the first embodiment of the present invention, Fig. 2a shows the second embodiment, Fig. 3a shows the third embodiment, Fig. 4 shows the fourth embodiment, and Fig. 3d shows the fourth embodiment. 5 Examples are shown below. First, an overview of these embodiments will be explained.

Referring to FIG. 1a, the device shown in FIG. 1a (excluding the printer PIT) is a reading device that can be used both for digital copiers and facsimile mills, and is incorporated into the exterior case shown in FIG. It is something that The scanner SCR can scan A3 documents at 400 dpi (
The 6-bit original image data is read at a density of 6 bits/pixel (64 gradations) (pixel/inch), shading correction, MTF correction, etc. This is a device that converts it into a binary signal/pixel and outputs it. Note that these reading densities and the number of gradations are just examples, and the reading density and the number of gradations are not limited to 400 dpi and 64 gradations).

The document surface DOC is irradiated with light from a light source 5, and the reflected light is received by an image sensor 7 with 5000 pixels in order to read the A3 document in the horizontal direction (297+m) at 400 dpi.

The image sensor 7 converts the optical signal of the document DOC into an electrical signal, and the amplifier 22 amplifies the signal to a predetermined level. Next, the analog signal whose voltage level differs depending on the concentration is converted into a 6-bit digital signal by an A/D converter 23.
That is, it is converted into image data.

Next, the circuit 24 performs shading correction to correct variations in sensitivity of each element of the 5ooo pixel sensor 7 and uneven illuminance of the light source 5 in the lateral direction of the A3 document.

In the embodiment shown in FIG. 1a, the scaling process is performed after this shading correction. That is, main scanning direction magnification M, 1&28 performs magnification processing in the main scanning direction X, immediately after this magnification processing, performs MFT correction in the main scanning direction First, magnification processing in the sub-scanning direction Y is performed, followed by MTF correction in the sub-scanning direction Y. These scaling processes can also be performed before the shading correction circuit 24 or after the MTF correction (29).

The arithmetic unit 28 performs magnification processing in the main scanning direction X and MT [
'After the correction, the circuit 29 performs magnification processing in the sub-scanning direction Y and MTF correction, and then converts the magnification image data into 2
1111 depending on the threshold level of the value conversion circuit 30
Binarize it into 1 or IJOLj and output it to the printer PRT (or transmission processing unit). Alternatively, the gradation processor 31 converts it into 1'' or II OII, which has halftone expression, and outputs it to the printer PRT (or transmission processing unit). It shows.

In the flow of image data, magnification processing and MTF correction in the main scanning direction Microprocessor 35, RAM 3 and sampling circuit 6
It is executed by a variable magnification processing device consisting of 4+65.

These magnification processing devices 28 and 29 are respectively.

A function to determine the position of the new sampling point i after scaling, a function to extract the original image data at the original image data positions x and y around the new sampling point i, and a function to extract the new sampling point i and the extracted original image data position. It has a function of calculating variable-magnification image data and a function of correcting the MTF of the variable-magnification image data from the distances to x and y (Ji) and extraction data. The configuration of the main scanning direction magnification calculator 28 is shown in FIG. 1d.

The sub-scanning magnification arithmetic unit 29 performs the magnification processing and MTF correction in the sub-scanning direction Y. The configuration of the sub-scanning magnification arithmetic unit 29 is shown in FIG. 1e.

In FIG. 1a, the latch 25. Data distributor 2
6. RAMI, RAM2 as line buffer memory
and data selector 27.

In the future, when determining the sampling point In the interpolation method using two pixels (the embodiments shown in Figures 1a, 2a, and 4), the data are grouped every two pixels, and in the interpolation method using four surrounding pixels (the example shown in Figure 3a), the data are grouped every four pixels. By the way.

For example, in Figure 12, the new spring points are Sij and Si.
If the data is between
j and Sij++ (in the embodiments shown in FIGS. 1a, 2a and 4) or 5ij-1, Sij.

This means that S IJ + l + S 1jss 2 (in the embodiment of FIG. 3a) is taken out at once.

Here, the aforementioned methods ① and ② are interpolation methods using two peripheral pixels (the embodiments shown in Figs. 1a, 2a, and 4);
Method ■ is an interpolation method using four surrounding pixels (example shown in Figure 3a)
It is.

A specific method can be implemented by storing the original image data Y (FIG. 6) that is sequentially inputted in synchronization with the data clock DCLK in the latch 25 (delay memory of the DCLKI pulse cycle) using DCLK. For two pixels, one stage of latch 25 (the embodiments shown in Figures 1a, 2a, and 4) is used, and for four pixels, three stages of latches 251 to 253 (3a) are used.
This can be realized by the embodiment shown in the figure.

Next is RAMI and RAM2 for line memory.

Input here is a memory that stores 5000 blocks of two pixels (in the embodiments shown in FIGS. 1a, 2a, and 4) or 4 pixels (in the embodiment shown in FIG. 3a).

It has a two-stage configuration for output, and when one (RAMI) is an input, the other (IIAM2) is an output, and when one line ends, the input and output are reversed. This is done by giving the output a of the T flip-flop 36, which performs an inverting operation with the line-synchronized Hals LS''/NC, to the data distributor 26, and a
but! In the case of (2), the data distributor 26 is used as input/output and the RA
This is done by designating M1 to write (W), giving another output to the data selector 27, and when b is L, the data selector 27 is set as the B output to read the RAM 2 (R).

The addresses of this line memory RAMI and RAM2 are input (written) by the counter 3g in the DCLK cycle.
, 43;) is used as is, but this address is changed at the time of output (reading). The address at the time of output is the sampling point r of the original image data immediately before the sampling point i of the scaled image data.
1x = J i.

When the sampling point i of the variable-magnification image data is certain.

When it is between Sij and SIJ+1, and the next sampling point is again between Sij and Sijyal.

Stop the read address counter, S ij + 2 and S
When it moves between ij+g, the read address counter is incremented by two, and when it moves between Slj+I and Sij+2, the read address counter is incremented by one as usual.

When enlarging (Rx top 100), the position of the new sampling point is determined by the operation of incrementing the counter by one and the operation of stopping the counter. When reducing (Rx<100), the position is determined by a combination of operations that advance the counter by one and two. In this device, the reduction is considered up to 50%, so the counter may be incremented by one or two, but if the reduction is less than 50%, it may be incremented by three or more.

Information about where and how many times the read address counter should be incremented is determined by the microprocessor 35 according to the magnification Rx%.
is pre-calculated. The original image data position X immediately before the sampling point i of the scaled image data is 100 i / Rx = where star 1 to position is O, the sampling pitch P of the original image is 1, and the magnification is Rx (%). J i ten Ri −=<4
)i = 0.1, 2, 3. ... Ji: integer, Ri: decimal integer Ji.

That is, if the sampling point i is between Sij and Sxj+1, the sampling position X of the original image data is Ji. Therefore, as i increases, 100 i
/ When the integer part Ji of Rx increases by one, the read address counter also advances by one, and as i increases, it becomes 1004 / R
When the integer part Ji of x increases by two, the counter also increments by two, and if the integer part Ji of 100 i / Rx does not increment by one, the counter also does not increment. / The decimal part Ri of Rx is S
The distance γl between ij and i-corresponding position -Q- is obtained.

This distance data γ! will be used later in the scaling image data calculation.

The microprocessor 35 calculates i=0 to R in the above equation (4).
Calculate up to x-1. That is, the integer j is obtained by calculating equation (4) with i=0. and decimal R8゜i = 1 (
4) Integer J1 and decimal R1 calculated by formula, integer J2 and decimal R2 calculated by formula (4) when i=2,...
・, integer JR by calculation of equation (4) at i = Rx-1
-1 and the decimal number RR-1. In this way i =
If only the integer Ji and decimal Ri from O to Rx-1 are calculated, this can be applied to the entire line length of the original image data. That is, in all cases, the sampling point of the variable-magnification image data has a period of every Rx, so 1=Rx
The value i=O may be assigned to , the value i=1 is assigned to 1=Rx+1, the value i=2 is assigned to 1=Rx+2, and so on.

In the process in the sub-scanning direction, Ji and Ri may be similarly calculated using the magnification ratio Ry to set the sampling line.

In all embodiments of the invention described below, i=0 to Rx, Ry-i
Calculation of Ji and Ri is performed when the magnifications Rx and Ry (%) are specified before the start of the reading operation,
Ji and Ri corresponding to Rx and Ry are converted into data Δl and Bi that match the hardware, and those corresponding to Rx are stored in RAM3 (Fig. 1a), and those corresponding to Ry are stored in RAM4 (Fig. 1e). Figure).

When image a reading is started, that is, during scaling processing, 1 is changed to a larger value by 1 in synchronization with the data clock DCLK, and the data (Ai, B i) corresponding to i is stored in RAM3.
The data (Ai, Bi) corresponding to the i-th line is read out from the RAM 4 by changing the address to a larger value one by one in synchronization with the line synchronization pulse LS'/NC.

Note that as another embodiment, a dedicated microprocessor or arithmetic means for performing the above calculation is provided, and in parallel with the scaling process, equation (4) is calculated in synchronization with the data clock DCLK, and line synchronization is also performed. Equation (4) is calculated in synchronization with the clock LS'/NC, and the integer part Ji of 100i/Rx, Ry, that is, the original image data sampling position X,
Alternatively, the line sampling position y may be used as an address, and the decimal part Ri may be used as the distance data r1, which is a parameter for calculating variable-magnification image data.

Next, the relationship between reading original image data from the line buffer RAM 1 and RAM 2 and variable-magnification image data calculation will be explained.

The embodiment shown in FIGS. 1a, 2a, and 4 is a line memory RAM 1 in which variable-magnification image data is calculated (■ or ■) based on two-pixel original image data Sij, SIJ+l, and R1. and RAM 2, 6-bit original image data is alternately input line by line in synchronization with DCLK, and at this input, the latch 25
At the same time, SIJ+1 is obtained without passing through the latch 25, and 6-bit Sij and Sij layer 1 are lined up to form 12-bit data.L words of 12-bit data are written alternately to RAM1 and RAM2 line by line. Since data is read from the other in units of 1 word (12 bits) when one is being written, the arithmetic unit 28 has the following:
5ij (6 bits) and Sij or I (6 bits) are given at one time.

In the embodiment of FIG. 3a, there are three stages of latches 251 to 253, and their latch data 51j-1°Sij and Slj+1 and data SIJ+2 that do not pass through the latch are combined into a parallel 24-bit word with 6 bits each. Been,
It is written to RAM 1 and RAM 2 and read from them in parallel 24 bits simultaneously. Therefore, the arithmetic unit 28 stores 5ij-1 (6 bits L 5IJ
(6 bits) esxj Yul (6 bits) and Slj+
2 (6 bits) is given.

Note that the latches 25, 251 to 253 are connected to the data selector 2.
7 and the arithmetic unit 28, the RAM 1, 2 may be configured to read and write only 6-bit 1 data for a line. In this way, the transmission of variable-scale image data for -line is reduced to one pixel (for the case corresponding to Fig. 1a).
Or, there is a delay of 3 pixels (corresponding to FIG. 3a).

In either case, the memory capacity of nAM1 and RAM2 is 6 bits x 1 line number. Therefore, it is effective in reducing the line buffer memory capacity in a long-range usage mode in which a delay shift of several pixels is noticeable.

Here, when RAM1 is in the write state (a=H, b=L),
In normal operation, the address counter 38 advances in cycles of DCLK, but RAM1 is in the output state (a
=L, b=H), the sampling position of the original image data li! A read address setting method for reading image data of x(Ji) will be described.

The first method is to change the frequency of the count clock to the address counter. Let the frequency of data clock DCLK be &fo.

The frequency fR when changing the magnification by R% is.

f R= f, ) −100/R(Hz) ”・(
5).

In this method, the deviation of f with respect to fo becomes the deviation of the sampling points of the original image and the variable magnification image, so it is accurate and reliable. When reading RAM1, 2, the address counter is moved by f, and the output of RAMI, 2 is set to D again.
By sampling (latching) with CLK, desired composite data can be obtained. With this method, information about the integer Ji is unnecessary in the calculation result of equation (4) described above. Therefore, in this embodiment, the magnification ratio Rx%
For example, if 50 to 400% and the minimum unit of Rx is 1%, the pulse f R = f 0400/ of 350ffi.
Rx is required. This is created using a dedicated microprocessor.

The second method first focuses on the integer Ji in the calculation result of the above-mentioned equation (4), and then calculates the previous scaling image data sampling position ff.
1Xi-t and the current sampling position Xi: (1) When the integer part increases by one during reduction (Ji Ji-1=1) Ai=H The integer part increases by two (Ji -Ji
-t = 2) When Ai = L (2 kanda) When the integer part increases by one (Ji-Ji-t = 1) When Ai = H the integer part does not increase (Ji-Ji-
1=0), the sequence [Δl] of Ai=L is expressed as i
Define from =0 to Rx-1.

Write it into RAM3 (Figure 1a) (before reading). Similarly, in the sub-scanning direction, i=o to Ry-t are calculated and written into the RAM 4 (FIG. 1e), as shown in FIGS. 1a, 2a, and 3a.

Common to all of the embodiments of FIGS. 3d and 4.

In the embodiment shown in FIG. 4, as a count pulse,
When performing C0 scaling image data calculation in which a data clock DCLK and a pulse 2DCLK with twice the frequency of 0CLK are prepared, Ai is read from RAM 3;
= 0 to R-1 are read repeatedly. In the embodiment of FIG. 4, when reduced (Rx<100), the count pulse of the address counter (38 or 43) for reading the line memory (nA old or l'lAM2) is Ai=
When Ai=L, switch to DCLK. When Ai=L, switch to 2DCLK. When expanding (Rx≧100),
By ANDing the count pulse A1 of the address counter 38 or 43 and DCLK, A
Count up when i = I-1, A i = L
Do not count when . The above also applies to the specified magnification Ry in the sub-scanning direction.

All embodiments of the invention have an I AM 3 and a RAM 4, where RAM 3 and RAM 4 contain (4) values for Rx and Ry calculated by the microprocessor 35.
Stores the above-mentioned A1 based on the result of the expression. These R
AM3 and RAM4 also store data Bi that differs in each embodiment. The contents of B1 will be described later.

In this way, before image reading, lIAM3 and IIAM4
Ai is stored in , and during image reading, Al and B are stored in RAM3 in synchronization with data clock DCLK, and IllAM4 in synchronization with line clock LS'VNC.
Read out i.

When the read address in the main scanning direction -1 +
SIJ! SIJ+I + SIJ+2 (3rd a)
(Embodiment shown in the figure), along with the readout, the configuration of the arithmetic units 28 and 29 for operating the variable-magnification image data becomes simpler, as will be described later. Note that the data Ai read from the RAM/I determines the extraction position of line data in the sub-scanning direction Y.

In the count pulse switching method of the embodiment shown in FIG. 4, when Ai=L during enlargement (Rx, Ry≧100).

ENA of counters 38 and 43 [lLE terminal is set to L,
Counting may be stopped.

A third method is implemented in the embodiment shown in FIG. 1a. The address counter 38.113 continues to count up based on the data clock DCLK. In addition to the address counters 38 and 43, there is another up/down counter 39, which is used when expanding (Rx≧1
00) specifies down, and when reducing (Rx>100), specifies up. And this up/down counter 39.
44 is DC so that it counts only when Ai=L.
Input the AND (logical product) of LK and Ai.

As a result, for example, during reduction, the amplifier down counters 39 and 44 are set to l when Ai=L, and the adder 37.
42, address counter 38;

Add 1 to the value of 43 and use it as the read address of RAMI and RAM2. Furthermore, at the next Ai=L, the up/down counter 39.44 is set to 2, and the address counter 38.4 is set to 2.
The position X (Ji) of the sampling point is determined by adding it to the count value of 3.

In the case of enlargement, it is necessary to read the read address without shifting it by 1, and at this time the address counter 38.

Since 43 counts up, in order to compensate for this, the up/down counters 39 and 44 are subtracted one by one as Ai=L.

The sampling position designation in the sub-scanning direction is also the same as above.

Next, variable magnification image data in the main scanning direction (X variable magnification image data)
The calculation will be explained. The same applies to variable-magnification image data calculation n (Y-variable-magnification image data calculation) in the sub-scanning direction. 1st
The embodiment shown in FIG. In this embodiment, the above-mentioned method (2) is carried out.Execution techniques for these methods will be explained.

(2) Nearest pixel setting method (embodiment shown in FIG. 1a) The calculation method of this method is relatively simple.

In FIG. 5, the variable-magnification image data sampling position i (closer to the end in FIG. 12) between Sij and SIJ+1 may be selected.

When the microprocessor 35 calculates the integer Ji and the decimal Ri based on equation (4), the decimal Ri is the distance fllr1/P between degrees and SiJ (P is the sampling pitch of the original image data, and in the embodiment P=1) is 0.
If it is less than 5, select Sij, if it is greater than 0.5, select Sij.
1J+1 may be selected.

In the embodiment shown in FIG. 1a, when the microprocessor 35 calculates Jl and R1 and calculates the aforementioned Ai, if r1/P is 0.5 or less, Bi==II,
If it is larger than 0.5, the sequence Bi that sets Bi=L is also calculated and written to the same address in the RAM 3 along with Bi'@Ai. This is processing before image reading. When image reading starts, R is synchronized with data clock DCLK.
Read Ai and Bi from AM3, use Bi as a select signal, Bi=! 1 to select Sij, Bi=L
In this embodiment, the selection of Sij+t is sent to the data selector 80XA (FIG. 1d) of the arithmetic unit 28.

■Adjacent pixel distance linear distribution method (Figure 2a) This method is
It becomes more complicated. This is because the above-mentioned equation (1) must be calculated. In this case, the interlayer is the distance r
The accuracy is 1/P or r2/P. Is it okay to consider it to the first decimal place, that is, in increments of 0.1, or do I need to look at it more closely?
The question is whether the degree of division, ie, 0.25 increments, is sufficient. This problem lies in the question of how much precision is required for a digital copier or facsimile system, and from the perspective of the six arithmetic operations that correspond to the required image quality in a digital copier or facsimile system, r 1/P .

It is preferable that r2/P is the reciprocal of a power of 2. This is l/2.1//1.1/8. This is because such operations are possible only by bit shifting 1- of the target data.

First, from the calculation result of equation (4), Ri==rl/P
Divide into 0.25 (1/4) increments. That is, Ri
The minimum unit of is 178, and the area division of Ri is 1/4.

-As an example, let's divide it into 1st order.

When 0≦r+ /P<1/8, Ri=rl /P=0
．． When Bi=01/8≦rl/P<3/8, R
i=rl/P=1/4. Bi=1378≦rl/P
When <5/8, Ri=rl/P=1/2. Bi
=2578≦r+ When /P<7/8, Ri=rl
/P=3/4. I'3i=3 where 778≦r1/
When P<1, -9- and Slj+1 are at the same position, so there is a way to create such a classification and set Bi = 4, but in this case, 3 bits are required for Bi, so , from the hardware configuration, in this case X is 1
Carry up the integer Ji by one, set the decimal Ri to O, and the main value is between SLI+I and Sij or 2,
It is preferable to set Bi=0 because B1 can be a 2-bit signal. Similarly to the above ■, this Bi is combined with Ai to 1
Write to the same address of 1AM3.・In Figure 2a, which implements this method, the distance divided into four (Bi=
0 to 4), A-3ij+B-5ij, 1 = O
ik...(6) However, A is a coefficient corresponding to rs/P.

B is a coefficient corresponding to 2/P.

Slu and Sij+1 are the contents of the 6-bit data.

Oik is the content of variable-magnification image data (6 bits).

It is.

Since A and B are determined, four ways of ASij and B-3 are determined by the
ij, 1 are calculated, one of which is Bi-compatible and selected by the data selectors 28b and 28c, and the adder 28d
Then, variable-magnification image data Oik is obtained.

In the embodiment shown in FIG. 2a, the coefficients A and B corresponding to Bi are set as shown in Table 1 below.

, Table 1, 1/2.1/4, and other inverse numbers of powers of 2 can be obtained only by bit shifting of the signal lines, making the hardware configuration very easy. FIG. 2c shows a modification of the X-direction variable magnification image data calculator 80xB shown in FIG. 2a. The X-direction variable magnification image data calculator 80Xn shown in FIG. 2c is composed of a ROM 28g. 5ij (from the minimum value to the maximum value of 6 bits) in advance,
Sij+s (minimum to maximum value of 6 bits) and [3i
Calculate the variable magnification image data Oik determined by
It is written to ROM28g.

During image reading and magnification processing, set Sij+Sij+t to R.
The variable-magnification image data 0ik is read out as the address of the OM28g.

Sij is 6 bits, Sij and 1 are 5 bits (coefficient B is 1)
Since Bi is 2 bits, the ROM 28g can be an 8 x 8 bit ROM with a 13-bit address, so the calculations to be performed in advance can be done without much difficulty.

The hardware configuration for calculating variable-magnification image data becomes extremely simple.

■Cubric function convolution This method requires extremely complicated calculations as shown in equation (3) above, and seems unsuitable for hardware implementation, even when compared to the methods described in (1) and (2) above.

Can perform accurate magnification changes.

This method also has the problem of distance accuracy, as in the case of ■, but here we will also consider the case where γI/P is divided into four parts as in the case of ■.

The division method is also exactly the same as ■.

Equation (3) above can be simply rewritten as A-3ij-1
+B・Sij+C・Sij+1 +D−3ij ya 2=O
ik...(becomes a force. Since the denominator of equation (3) is a normalization coefficient, it can be excluded from the parameters.

1) "From the above equation (2), γs /P-0, 'l/4.
Calculating A, B, C, and D in the four cases of L/2.3/4 results in the following.

Similar to the direction variable magnification image data calculator 80XI3, there are four ways
-+-1+D-8IJ+2 (0 to 63 for Sij etc.) are prepared.

There is a method of selecting one by one according to Bi and adding the four. However, in this case, unlike in the case of ■, each calculation is a little more troublesome, and the hardware is also a little more complicated.

Therefore, in order to reduce the burden on the hardware as much as possible,
Rewrite the coefficients A, B, C, and D by approximating them as shown in Table 2 below. However, at this time, A + B + C + D = 1
It is necessary to become

Table 2 In this case, the denominator of the coefficient is 8 or less, making counting by hardware much easier. The X-direction variable magnification image data calculator 80XC shown in FIG. 3a uses the coefficients in Table 2 to calculate
In this example as well, a ROM may be used as the X-direction variable-magnification image data calculator 80Xc as shown in FIG. 2C. When doing so, R
Use OM63.

The address of ROM 63 is 3 bits at 5ij-1.

6 bits for Sij, 5 bits for Sij and 1, Sij+2
3 bits for Bi and 2 bits for Bi, for a total of 17 bits.

Since the memory amount becomes 128 by 1-, RO
It is a little difficult to calculate the data to be stored in M6'3 in advance. But if this method.

The hardware for variable fn LI image data performance is also simplified.

Next, MTF correction will be explained.

In the first method, correction coefficients are set in advance in accordance with the magnification. That is, the MTF correction calculation formulas in which the correction coefficients (filter coefficients) shown in FIGS. 14a to 14d are set are prepared, one of them is specified using the magnification R, and the MTF is corrected. Immediately after the main scanning X direction magnification image data calculation (the output of the data selector 80XA in FIG. 1d, the output of the X direction magnification image and other data calculation unit aoxn in FIGS. 2a and 2c, and the The output of the X-direction magnification image data calculator 80XC in FIG. 3c) does not perform magnification processing in the Y-direction, so only M TF correction in the X-direction is performed.

A correction coefficient (filter coefficient) V~2 shown in FIG. 13a,
From the image data distribution shown in Figure 13b.

The MTF-corrected value Mik of the spout image data Oik is M
ik=Y・Oi −1k+V' Oik −1+l?
Oik+ + +Z・Oi−1 +X・Oik...(
8) It becomes. This is, Mik = V・Oi−+ +W−Oik, t+X/2
・Oik+Y-01 -t +Z-Oi-t k+
Since it is X/2・Oik, MFT correction only in the X direction.

Mik= Vl)ik-1+W・0ik-1+X/2
()ik...(9) may be the MTF-corrected value. MFT in Y direction only
In the correction, Mik=Y・Oi−lk+Z・Oi−1k+X/2・O
ik...(10) may be an MFT-corrected value.

Therefore, in the X direction 14TF correction calculator 110XA of the first embodiment shown in FIG.
The four sets of MTF correction calculation formulas in which the correction coefficients shown in Figures 4c and 14d are substituted into Formula (9) are executed respectively, and the value calculated by the calculation formula corresponding to the specified magnification R is sent to the data selector. I try to have it removed at 98.

The second embodiment shown in FIG. 2a and the third embodiment shown in FIG. 3a also perform MTF correction in this manner.

In addition to the above-mentioned method of changing the correction coefficient, a second method is to perform a cross calculation (which also takes MTF correction into account when calculating magnification). In Fig. 6, h (r) indicates that the MTF correction of the input system is 100.
%, the variable magnification image data calculation (the above ■
) is the interpolation function used in However, in actual scanners, it varies depending on the reading speed and density, but 10
It is about 40%. The SCR of the scanner targeted by the embodiments described later is about 15%, and this frequency response H(ω) approximately becomes a curve shown in FIG. 15.

This curve is.

−〇, 2ω2 11(ω) = e (Ilhc) = 0.1
4), and the interpolation coefficient h(r) obtained by this Fourier transform is shown in FIG.
The magnification processing is performed in a corrected form. here.

As in the ■ method, r 1 / P = 0.1
/4.1/2t3/4, and calculate the coefficients A-D of equation (7).

In this case, the calculation is approximated by simple hardware and easy calculation. Also, at this time, if the positions of Sij and erect coincide, the term 5ij-1 is also required in addition to the term in equation (7).

E-5ij-2+A-Sij-1+B-5ij+C-5
ij 1 + I) Sij 2 = Oik (11). This Oik has undergone the X-direction scaling image data calculation and MFT correction, so the X-direction MT [
'Corrected variable magnification image data Mik.

The coefficients A-E are as shown in Table 3 below.

Table 3 This performs ■X-direction scaling image data operation W using the coefficients of Table 2, than in the case of (the example of FIG. 3a),
This shows that the X-direction magnification image data calculation and the X-direction MTF correction calculation can be performed simultaneously by using one more coefficient. The X-direction magnification image data calculation, which has been subjected to MTF correction based on the coefficients shown in Table 3, is performed in the embodiment shown in FIG. 3d.

The above is the calculation of magnification image data in the main scanning direction
l" correction calculation has been explained. The variable magnification image data calculation in the sub-scanning direction Y and the MTF correction calculation are performed in the same way. The difference between the two is whether the calculation is performed by focusing on the alignment of the original image data in the main scanning direction The difference is whether the calculation is performed focusing on the arrangement in the scanning direction Y.

Next, the hardware configuration and operation of the embodiment of the present invention will be explained.

In the first embodiment shown in FIG. 1a, the original image data read by the scanner SCR is sent to the shading correction circuit 24 for every l line, and the data for one line is sent to the parallel 6 One circuit 24 receives one period of the line synchronizing pulse LS'/NC with the same data structure and the same transfer format. Each word in the line is synchronized with the data clock DCLK.
applied to latch 25 and data distributor 26. circuit 25
When the output of the latch 25 is the data Sij++ of a certain pixel, the output of the latch 25 is the data S1j of the previous pixel,
These data Sij and SIJ+1 are applied to the data distributor 26 in parallel 12 bits.

On the other hand, the T flip-flop 36 outputs the line synchronization pulse L
Since the signal levels of the outputs Ω and q are inverted every time one pulse of SvNC arrives, for example, when data on the first line is given, the data distributor 26 gives 12 bits of input to RAMI, and is specified for writing. At this time, the data selector 27 provides the 12-bit data at the input terminal B to the arithmetic unit 28, and the RAM 2 is designated for reading. When the second line of data is provided to data distributor 2G, data distributor 26 provides 12 bits of input to IIAM2, with IIAM2 designated as floating. At this time, the data selector 27 selects 1 of the input terminal A.
2-bit data is given to the arithmetic unit 28, and RAM1 is designated for reading.

In this way, the data of the two adjacent pixels on the n-th line are written in parallel to the IIAM 1, while the data on the two adjacent pixels on the n-1th line are read out from the RAM 2 in parallel. The data of the two adjacent pixels of the +1th line are input into IIAM2 in parallel, while the data of the two adjacent pixels of the nth line are read out from IAMI in parallel.Similarly, the liA old and IIAM2 It is switched by the pulse LSYNC and designated for writing and reading alternately.In this way, 12-bit data, which is a parallel combination of the data of two adjacent pixels of the rl line, is written to the RA old or RAM2. Sometimes, the nth
12-bit data, which is a parallel combination of data of two adjacent pixels of the -1 line, is read out from IllAM2 or RAMI and given to the arithmetic unit 28. That is, the original image data is given to the arithmetic unit 28 in the form of data of two adjacent pixels arranged with a delay of exactly one line from the data outputted by one circuit 24. In this way, with respect to the input of data to the buffer memories RAMI and RAM2, the reading of data therefrom is delayed by exactly one line.

The sampling circuit 64 determines the RAMI read/write address, and the sampling circuit 65 determines the RAM2 read/write address.

First, the sampling circuit 64 will be explained.

When RAMI is specified for writing, signal a=H
, b=L, and the AND gate 40 is off (gate open)
Therefore, no count pulse is given to the up/down counter 39, and its output remains at 0. Since the data clock DCLK is given to the address counter 38 as a count pulse.

Each time one pulse of the data clock DCLK arrives, the count is increased by one. Adder 37 includes counters 39 and 38
Add the Karan I data of , sum data to RA old,
Give as address data. As a result, 12-bit data obtained by parallelizing the data of two adjacent pixels is sequentially written into the RAM 1 in synchronization with the data clock DCLK. In other words, all of the data for one line is It
Written to AM1.

When IIA old is specified for reading, a=L
, b=1-1, when the signal C is L, the AND gate 110 is on (gate open) and the data clock DCLK is given to the amplifier down counter 39 as a count pulse. When the signal d1=tl (reduction), the count is counted down by 7, and when dl=L (enlargement), it is counted down. The signal C is the data A1 already explained and is used to control run 1 - stop/advance. At the time of reading, the sum of the values of the counters 39 and 38 from number 1 becomes the read address of the RAMI. If c=L,
When dl=H, every time one pulse of DCLK appears,
The counter 39 counts up by 1, the read address of nAMl advances by 2, and when dl=L, DCl,
Every time the I pulse appears, the counter 39 counts 1.
- Note that the read address of RAM l stops when it goes down.

c=Ai.

The sampling circuit 65 has exactly the same configuration as the sampling circuit 64, but differs in that the a signal is added to the AND gate 45 instead of the b signal. This reads IAMI b = u, a
=L), IIAM2 is written and I
This is because when the IA old is written (b = L, a = H), the RAM 2 is read, and the read address is the sum of the count values of the counters 44 and .13.

Here, l\i will be explained. microprocessor 3
5 is an image reading start instruction (ST changes from L to H)
In response to this, read the specified magnification ratio Rx%, and based on this, calculate Ji and R1 for each of i=0 to Rx-1, and if Rx<100 (reduction), J
i-Ji-1≧2 and Ai is L, Ji-Ji-+≦l
Let Ai be I, and if Rx≧100 (enlargement), J
When i-Ji-1≧1, Ai is H, Ji-Ji-, +≦
At O, Ai is set to L, and when Ri≦0.5, Bi is set to 11.
and when Ri > 0, 5, Bi is set as L,
Ai and Bi are stored at address i in IIAM3 (FIG. 1a). In this memory operation.

Before writing the data Ao and I30 corresponding to i=0, the microprocessor 35 applies one pulse to the OR gate 49 to load data indicating Rx into the address counter 48. Then, when Ao and BO are given to 11A at 3, one pulse is given to the OR gate 51, the address counter 48 is incremented by one, and the data Δ1 corresponding to i=1 is given.
and B1 are given to RAM3, and then one pulse is given to or game 1-51. This operation is repeated until 1=Rxl. Due to this.

Data A corresponding to i20 at address 0 of It A M 3
. and BLI is data A corresponding to address l with i=1
1 and 111,...at address Rx-1, t=Rx
-1 corresponding data Δtq-s and BR-1 are included in jF.

Note that the above description is based on Ai corresponding to Ry in the sub-scanning direction.
This also applies to the processing of Bi and their writing to RAM 4. However, Rx is Ry and RAM
3 is read as RAM4, and the data clock is read as line clock.

Then, when the image reading is instructed to the scanner SCR and the image reading actually starts, the line synchronization pulse LS'/
Data indicating the specified magnification Rx% is set in the address counter 48 by the NC, and the counter 48 increments by 1 every time one pulse of the data clock DCLK appears.
Data AO and BO corresponding to i=0 are read by incrementing the read address by 1 each time DCLK is cursed by one pulse.
1=R-1 corresponding data A R-1 and ThR-
'1' are sequentially read out, data Ai is given to sampling circuits 64 and 65 as (C), and data 13i is given to data selector 80XA of arithmetic unit 28.

Data selector 80XA selects Sij when Bi=H.

When Bi=L, Slj+1 is output as variable-magnification image data Oik. This output operation is synchronized with the data clock DCLK, and the scaled image data Oik obtained by scaling in the L to X directions is
The X-direction MTF is given to the TF correction calculator 100XA.
The corrected magnification image data M i k is provided to the sub-scanning magnification calculator 29 . The image is subjected to magnification processing in the sub-scanning direction Y and MTF correction in the circuit 29, and then provided to the binarization circuit 30 and the gradation processor 31. In this embodiment, the 1-gradation processor 31 includes a ROM having 64 types of gradation expression data distribution patterns corresponding to densities, a cyclic line counter initialized at 64 counts, and cyclic data initialized at 64 counts. It has a clock counter, and the read address of the ROM is set by Oik, line count data, and data clock count data. That is, one pattern in the ROM is specified using Oik, the main scanning address of that pattern is specified using a data clock counter, and the sub-scanning address is specified using a line counter, and image data starting from 1 pin 1 in the pattern is read out. When the microprocessor 35 instructs to output binary data (i=H), the goo 1-circuits 32 to 34
When instructing the output of the binarization circuit 30 to output one gradation data (i=L), the output of the gradation processor 31 is output to the printer PRT.

In the X-direction MTF correction calculation unit 100XA, the latch 81 delays the scaled image data (Oij) by one period of the data clock DCLK, and the latch 82 further delays the data by one period. As a result, the scaling image data 0ik-+ and Oik for executing equation (9) are stored in the latches 82 and 81.
Oik+1 is obtained at the input side of the latch 81. These data are provided to XMTF operation 1i100XA.

XMTF operation W100XA (7) Adder 83 is Oik
(7) Data obtained by shifting all 6 bits by 1 bit upwards (2.0ik) and data obtained by extracting only the upper 5 bits of all 6 bits 1- (112.01k) are given, and the adder 83 outputs 5/2 - Provide data indicating Oik to the adder 94. Adder 84 provides data indicating the sum of 0ik-1 and Oikyil to complementer 90. The complementer is -(Oik-H
+Oik or 1) is given to the adder 94. As a result, the adder 94 adds the coefficients shown in FIG.
9) The MTF correction calculation value substituted into the formula is sent to the data selector 9.
8 input terminal A.

Add! 7 vessels 85, 86. The complementer 91 and the adder 95 are
The MTF correction calculation value obtained by substituting the coefficients shown in FIG. 14b into equation (9) is applied to the input terminal B of the data selector 98.

The addition rt87, the complementer 92 and the adder 96 are
The MTF correction calculation value obtained by substituting the coefficients shown in FIG. 4c into equation (9) is applied to the input terminal C of the data selector 98. Also,
Adders 8B, 89. The complementer 93 and the adder 97 provide an MTF correction calculation value obtained by substituting the coefficients shown in FIG. 14d into equation (9) to the input end of the data selector 98.

On the other hand, the microprocessor 35 directly reads 9 images 1);i
Then, check 18 constant magnification Rx, Ry, Rx, R
When y<100, the selection instruction data R old and old<2 for setting the A input to output are output to the data selector 98 and the data selector of the '/MFT arithmetic unit 100v, and when 100≦Ri, Ry<200, 8 Selection instruction data R111 and RR2 for setting human power as output are output in the same way, and when 200≦Ri and Ry<300, selection instruction data RRi and RR2 for setting C input as output are output in the same way, and 300≦ At the time of Ri and Ry, selection instruction data RR1 and RR2 for setting the D input to output are similarly output.

As a result, the XMTF calculator 28 uses the variable magnification image data Mi calculated using the MTF correction coefficient according to the specified magnification Rx.
k is obtained and given to the sub-scanning magnification calculator 29.

Next, the configuration of the sub-scanning magnification calculator 29 will be explained with reference to FIG. 1e.

The variable-magnification image data Mik subjected to the variable-magnification calculation and MTF calculation in the main scanning direction X is provided to the gate 103 of the sampling circuit 65'/ in synchronization with the data clock DCLK.

After Ai and Bi are written in RAM3, Ai and Bi calculated based on Ry are stored in RAM4. At the time of @image reading, the address counter 48
'/ counts the line clock LS'/NC and
Define the IAM 4 read address. Therefore, here A1 and Bi are the data clock DCL
Instead of K, i is increased by 1 for each pulse of line clock LSYNC (according to the progress of sub-scanning) (A
i.

Bi) is read out from RAM4.

address counter 43Y of sampling circuit 65'/;
The up/down counter 44Y, the anti-games 1-45Y, and the adder 42v have roughly the same configuration as the sampling circuit 65 in the main scanning direction (FIG. 1a), but they use the line clock s' instead of the data clock DCLK. /N
Count C. That is, the sampling position Y in the sub-scanning direction is determined. Call 1- of address counter 43Y
The starting point for the data was the start of image reading of page 1. It indicates the sub-scanning position, and the output data of the adder 42Y indicates the sampling position my in the sub-scanning direction. When both data match, that is, when the sub-scanning position for image reading matches the sampling position y, the comparator 102 provides an [I output to the latch 129 and the OR gate 130. Since the output of Uchi 129 is also given to this or game 1-130, the or game h13
0 is when the image scanning line No. is Ji(y) and Jx
+t(y+1), gate on No. 43 (1■) is connected to data gate 103. and andgate 108.109
give to While the data of the line at sampling position 1iWJi(y) and the next line arrive, the OR gate 13
Note that 0 generates Goo 1~Open (No. 3 (11)).

On the other hand, the data Bi read from the RAM 4 is set in the latch 131, and the OR gate 132 outputs the same data Bi over the two line section.

The R-S flip-flop 104 of the variable δ calculator 80Y corresponding to the data selector 80XA in FIG. It is set and reset by the signal t which becomes II in the next LSVNC. That is, the flip-flop 104 is set when the sub-scanning position reaches the sampling position (y), and is reset when the sub-scanning proceeds to the next time.

Since the same data Bi is output from the OR gate 132 across two lines (BS connection two lines) when this is set and when it is subsequently reset, the ant gate that receives the output Q of the flip-flop 104 -1-10
5, when the flip-flop 104 is set to cell 1 through the signal S and the data Bi is 1% (selecting the preceding line among two adjacent lines), the output of H is sent to the OR gate 10.
7 through data gate 103 and AND gate 10
8,109. The AND gate 106 receives the alternating output of the flip-flop 104.
When 4 is reset at 4n g' t and data Bi is L (instruction for selection of later input of two adjacent lines), 11 is outputted and sent through OR gate 107 to data gate 103 and AND gates 108 and 109. give. Gate 103 and AND gate 108, 10! J
When data Bi is l(, one image sub-scanning becomes sampling line No. y (Ji), 1
The gate is opened only in the line section, and when the data 13i is O, the image sub-scanning is performed on the sampling line No-y (
When the next line of Ji) is y+t(jj+1),
Gates will be open only in one line section. In this way,
When data [3i is I(, J calculated by equation (4)
The data of line No. y indicated by i is stored in the memory 29 for one line. When data Bi is L, J
The data of line No. y +1 next to i is stored in the memory 29 for one line.

The above is the variable magnification image data performance in the sub-scanning direction (this 1'X
In the Jliii example, this is selection of one of the sampling line and the next adjacent line).

Next, the MTF correction in the sub-scanning direction will be explained.
The scaled image data has been subjected to MTF correction in the sub-scanning direction using the lO) formula (that is, the setting of the scaled image data in the main-scanning direction and the sub-scanning direction has been completed, and the MTF correction in the main-scanning direction has also been completed). So.

Obtain the final data after completing all scaling processing and MTF correction. Line buffer 81'/and 82Y include
Each of them stores one line of variable-magnification image data that has been subjected to variable-magnification processing in the main scanning direction and sub-scanning direction and MTF correction in the main scanning direction. If the output image data of the buffer 82Y is Mi-1, the output image data of the buffer 82'/ is Mik one line later,
The image data arriving at the input end of the buffer 82V is Mik
This is Mi+1 which is one line later. these are,
It is applied to a YMTF operator 100Y having the same configuration as the XMTF operator 100XA shown in FIG. 1d, and the aforementioned RR2 is applied to the data selector (corresponding to 98) of the YMTF operator 100V.

The YMTF calculator 100Y converts 0ik-t into Mi-1k, Oik%Mik, and Oik+ in FIG. 1d.
Four equations (Fig. 14s, tib, 14c, and 14d in equation 10) in which t is replaced with Mi or 1k.
Calculate the equation (by substituting the coefficients in the figure) and output data showing one solution. This output is scaled image data for which scaling processing in the main scanning direction and sub-scanning direction has been completed, and scaling processing in the main scanning direction and sub-scanning direction has been completed.

Looking at the correspondence between the elements in FIG. 1e and the elements in FIGS. 1a and 1d, we see that the latches 129, 13 in FIG.
1. OR gate 130, 132° 133, variable magnification calculator 8
0Y and the data gate 65Y are connected to the sampling circuit 65 of FIG. 1a and the data selector ll0X of FIG. 1d.
This sub-scanning direction magnification calculation means corresponds to the main scanning direction magnification calculation means formed by the combination A. Buffer memories 81Y and 82Y in FIG. 1e correspond to latches 81 and 82 in FIG. 1d, which obtain a data delay of one pixel in the main scanning direction. It is a line buffer memory that obtains a data delay of one pixel in the sub-scanning direction.

The YMTF operation n N 100Y in FIG. 1e is the 14th
This is an arithmetic unit that executes the operation D (four sets) of equation (10) shown in Figures a to 14d and outputs data indicating the solution of one set.

Next, the process control operation of the microprocessor 35 will be explained with reference to FIGS. 1b and 1c.

Reference is first made to FIG. 1b.

When the power is turned on (step l), the microprocessor 35 sets the input/output board to the standby state level 1,
Clear internal registers, counters, timers, flags, etc. (Step 2: The word step will be omitted in parentheses below).

Next, the sampling position information calculation in the main scanning direction and RAM3
In order to write data to , the data Rx indicating the specified magnification change ratio Rx% in the main scanning direction is read and stored in the register Rsx (3x), and L is set in the output capo-hg (4x). That is, the AND gate 50 is turned off (gate closed) and the address counter 48 is set so that no count pulse is applied from the outside. Next, to the output port nl,
Set the data indicating the specified magnification change ratio Rsx% stored in the register Rsx (5x), and then register the address counter 48
Add to the preset data input terminal P of X. Then, one pulse is output to the output port f+ (6x), and R and sx are loaded into the address counter 48X. This means that the address counter 48x has been initialized (initial address setting).

Next, the microprocessor 35 sets ItWi to the write instruction level and sets lIAM3 to write (7x).
, sets the contents of internal address register l to indicate 0 (register clear) (8x). This means that the above-mentioned i20 has been set. Next, clear register j and set tl to register B1 and Ai (9
x). Then, the contents Bl of registers Bi and Ai are stored in RAM3.
and Ai (10x). At this stage, i
= 0, so BO=I at address R of RAM3.
I and A. =II has been written. Next, the contents of register i are incremented by 1 (llx), thereby changing the value of i to a value that is 1 larger than before. Next, since i is 2 or more (2 at this stage),
Compute the integer Ji and decimal Ri such as 100i/Rsx = Ji + Ri (13x), move the contents of the current computed value register ji to the previously computed value register j1-1, and
4ax), the integer J1 is stored in the calculation value register ji this time (14bx), and then in steps 15x to 17x,
Bi is set, and Al is set in steps 18x to 25x. Then output 1 pulse to output capo-1-h1 (2
2x), increment the write address of RAM3 by 1, advance the write address, and write the RAM3 at step 10x.
Write the set Bi and A1 into M3. Similarly, change i to a larger number (1lx), calculate Ji and Ri (13x), set Bi and A1 based on them and Rsx (15x to 25x), and set RAM
The write address of 3 is updated (22x), and Bi and Ai are written to RAM 3 (10x). In this way,
When 1=Rsx+1, all Bi and A1 corresponding to i=0 to Rsx-1 have been written to lilAM3, so the process advances from step 12x to step 60 in FIG. 1C.

Step 60 is composed of steps similar to steps 3x to 25x, but in those steps 3x to 25x, Rsx is set to Rsy, nl is set to n2, fl is set to f2,
IIAM3 is read as IIAM4, and hl is read as A2. That is, sampling position information Ai and scaling calculation information Bi are calculated based on the designated scaling factor Ry in the sub-scanning direction, and these pieces of information are written in the RAM 4 in correspondence with i. Then, the process proceeds from step 60 to control of the variable magnification process during image reading. Note that when proceeding from step 8x to step 9x, AO=11 is written to address 0 of the RAM 3, but this does not exactly correspond to Ji-Ji-1. This is because Ji-1 is unknown at this stage. However, when i is Rsx-1, the following (i = Rs
x), the counter 48X is initialized with a carry indicating that the Rsx count of the counter 48X has exceeded, and i is returned to 0, so i=0 and 1=Rsx are the same. Therefore, i=0
The operation of An in can be replaced with that of 1==Rsx. Then, J8-1 when 1=Rsx-1 is used as Jl-1. Therefore, in step 12x, 1=R
It is checked whether the calculation of Ai and Bi and the memory to lIAM3 have been completed up to sx. That is, i=0~Rsx-
It is sufficient to memorize Ai and Bi up to 1, but further 1=Rs
Even for x (which has the same meaning as i=O), Ai and Bi are calculated and stored in memory. When 1=Rsx, the counter 48X overcounts Rsx and sets the write address of RAM3 to O, so B is written in step 9x. and A will be rewritten to BR$X and ΔR5X. This leads to step 9x.

This means that the AQ written at 10x has been updated to an accurate value.

In FIG. 1c, when the process proceeds from step 60 to variable magnification processing control during image reading, the image reading start instruction signal ST is
It waits for It, which instructs to start reading (26), and while the reading start instruction does not arrive, it reads the input magnification instruction data Rx, Ry and uses it as the value stored in the registers Rsx, Rsy. Check whether they are the same (27),
If they are not the same, it means that the designated magnification RX or Ry has been changed, so return to step 3x in FIG. 1b and similarly calculate the data Bi and Ai and I(A Write to M3, as well as R
Data B1 and Ai calculation and RAM4 corresponding to y
Write to.

When the image reading start instruction signal becomes 5TfJ%H, check whether the scanner SCR is ready (28), and check whether the printer PRT is ready (29).
, if one is not ready, wait for both to become ready.

When both the scanner SCR and the printer PRT are ready, if binary image processing (document two-sentence image processing) is instructed, set 11 to the output port i (31) and output the output from the binarization circuit 30. The gate circuits 32 to 34 are set so as to be applied to the printer Pr1T, and when 1-gradation image processing (photographic image processing) is instructed, L is set to the output port 1 (32). Gate circuits 32 to 34 provide output to the printer I'R.
Set.

Next, the microprocessor 35 selects a specified magnification ratio register R.
Refer to the contents of 3X and check whether reduction or enlargement is specified (33x), and if reduction is specified, set 11 to output port d1 (34x), and use up/down. Counters 39 and 44 are set to count up. When expansion is specified by Rsx, set L to the output port di (35
), the up/down counters 39 and 44 are set to count down.

Next, the designated magnification Rx is Rx<100°100≦Ri
<200, 200≦Ri<300 and 300≦
Please check which range of Ri is 51x, 5
3x.

55x, 57x), when Rx<100, XMT
Set the selection instruction signal Ritt to (the data selector 98 of) the F calculation unit 100XA to one that sets the input to the output (one that instructs the output of the calculated value based on the coefficients in FIG. 14a); 100≦Ri (when 200, the data selector 98 of the XMTF arithmetic unit 100XA)
) to set the 8 inputs as outputs (instructing the output of the calculated value based on the coefficients in FIG. 14b) (54x), 200≦RX<3
When the value is 00, the selection instruction signal RRI to the XMTF calculator 100XA (data selector 98) is set to set the C input to the output (instructs to output the calculated value based on the coefficients in FIG. 14c). 56x), 300≦
When Ri, the selection instruction signal RRI to the XMTF calculator 100XA (data selector 98) is set to set the D input to the output (instructs to output the calculated value based on the coefficients in FIG. 14d). (57x). Then, the RAM 3 is read and set to 12 (36x).

Also, in step 70, 5, by logic similar to this,
Regarding Ry, determine whether it is reduced or enlarged.

The up/down of the counter /14Y is specified, the range of Rsy is detected, and the signal RR2 is set accordingly. Step 70 includes steps 33x to 35x, 51x
~ Consists of steps similar to 57x and 36x.

However, these steps 33x to 35x, 51x to 5
7 and 36x, Rsx is read as Rsy, dl is read as dl, and RAM 3 is read as RAM4.

Next, H is applied to the output port g to the cell 1 (37), and the AND gate 50 is turned on (gate open). Next, scanner S
H level start signal A to CR and printer PRT
Give TS (38).

In response to the ATS becoming 14, the scanner SCR starts image reading and serially outputs the line synchronization pulse LSYNC, data clock DCLK, and original image data line by line. is RAMI&:? The data on even numbered lines is transferred to RA.
When the data of the odd numbered line is written to M2 and the data of the even numbered line is written to II A
The data of the even numbered line is read from M2.
While data is being written to AM2, odd numbered line data is read from RAMI. That is, the original image data is stored in the line buffer memory RAMI, as shown in FIG.
It is written to and read from RAM2.

During this image reading, the address counter 48X is initialized by the line synchronization pulse LS'/NC and its own generated count-over signal (issued every time it counts the specified magnification Rsx%), and then the address counter 48X Count up the clock DCLK. As a result, the address that the address counter 48X adds to the RAM 3 becomes O when one line synchronization pulse LSYNC arrives.
, and then 1 every time DCLK appears one pulse.
It becomes a large value, and after the maximum number Rsx 1, the address counter 48X counts over, and then the address counter 48X counts over and initializes to 0 again.
The value becomes larger by 1 each time DCLK arrives. This is repeated during one period of the line synchronization pulse LSYNC.

Since RAM3 is set to read, Ai and Bi, i = O to Rx -1, are read out from RAM3 sequentially from i = O, and when 1 = Rx - 1 is read out, they are read out again from i = 0. DC
It is read out sequentially in synchronization with I and K, and Ai is given as signal C to inverters 41 and 4G, and Bi is given to data selector 28a.

c = Ai = 11 (Ji-Ji-t≦1 at the time of reduction
, when enlarged Ji-Ji-1≧1), the animation
1-40° 45 is turned off (gate closed), the count values of the counters 39 and 44 do not change, and the scaled image data is sampled at the same sampling pitch as the original image data (P=1). In this period,
The image magnification is l. In other words, the variable magnification image data.

This is the original image data (not thinned out or written twice).

In the case of c=Ai=L (Ji Ji-1≧2 at the time of reduction; J i -J i-s <1 at the time of expansion), the counters 39 and 44 are up-counting at the time of reduction, so
As the address counters 38 and 43 increment by one, the counter 39. Since /14 counts up, the arrival of one pulse at DCI increases the read address of RAMI2 by two, and the original image data is sampled every pixel. When enlarging, counters 3 and 33 count down, so counters 39 and 44 count down, contrary to address counters 38 and 43 incrementing by 1, so DCLK
Even when , the read address of RAMI2 does not change, and the data of the same pixel of the original image data is sampled in reverse.

Through the above sampling operation, the original image data is sampled at a pitch corresponding to the specified magnification Rx, and Bi=1
1 (Ri≦0.5), the data selector 80
XA converts the sampled original image data Sij to O
ik, and when Bi=L (Ri>0.5), the data selector 80XA outputs the sampled original image data Slj+l as Oik. The original image data sampled in this way is sent to the XMTF operator 11.
The MTF in the main scanning direction is corrected at 0XA.

In the sub-scanning magnification calculator 29 shown in FIG. 1e, the data Ai and Bi are read out from the RAM 4 in such a way that the readout of the RAM 3 is performed by counting the line clock LSYNC instead of counting the data clock DCLK. Ai and Bi are output to the sampling circuit 65.
'/ is given. As a result, in the sub-scanning direction, image data (in this case, intermediate data that has been subjected to magnification processing in the main-scanning direction) is obtained in the same way as the sampling in the main-scanning direction described above.
sampling is performed. Then, the sampled image data is subjected to MTF correction in the sub-scanning direction by the '/MTF calculator 110Y. Note that this YMTF calculator 110
The data RI12 is given to the data selector (corresponding to 98) of Y.

In this way, the sub-scanning scaling calculator 29 performs sampling of image data and calculation of scaling image data based on the Ry-corresponding data Ai and Bi read into the rlAM4, and Since the AτF correction is performed based on nR2, the variable-magnification Baiwei data calculation and MTF correction in the main scanning direction and the variable-magnification image data calculation and MTF correction in the sub-scanning direction are independent, and Rx and Ry Even if they are different, they are performed in a manner that is compatible with Rx and Ry, respectively.

As described above, in the first embodiment shown in FIG. 1a.

The variable-magnification image data is set using the method described in (2) above.

J2-1° Dream, 2a and 2b The main parts of the 2'A embodiment, which are mainly different from the first embodiment, are shown in 2a.
FIG. 2b shows only the parts that are different from the processing control operation of the first embodiment.

In this second embodiment, the main scanning magnification calculation unit 28 includes a main scanning direction magnification image data calculation unit aoxn and a main scanning direction MTF correction having the same configuration as the main scanning direction MTF correction calculation unit 110XA shown in FIG. 1d. It is composed of a computing unit 110Xn (not shown). The sub-scanning magnification calculator (
(not shown) includes two line buffers (not shown) each storing one line of image data, and aoxn
a sub-scanning direction magnification computing unit consisting of a computing unit (not shown) having the same configuration as; and a line by 7781 shown in FIG.
A sub-scanning direction MTF correction calculator (not shown) having the same configuration as the combination of Y, 82Y and YMFTWL calculator 100'/
It consists of To summarize, the second embodiment differs from the first embodiment only in the scaling processing arithmetic unit. Therefore, the second
The scaling processing computing unit of the embodiment will be explained in detail.

In FIG. 2a, the main scanning direction variable magnification image data calculator a
oxn calculates the scaled image data Oik using (■) described above.

That is, the four types of coefficients A in Table 1 and the image data 5ij (
0 to 63) is multiplied by the data selector 28b.
is applied to the input port a = d of. Furthermore, this a”
d corresponds to a - d in the right column of Table 1, respectively, where a contains all bits of Sij, that is, Sij, and b contains Sij
The data indicating the sum of the upper 5 bits of Sij and the upper 4 bits of Sij is stored in C, that is, 1/2Si
j is the upper 4 bits of Sij, 1/4 S
ij is given.

Further, data obtained by multiplying the four types of coefficients B in Table 1 by the image data SLj+1 is applied to the manual boats a to d of the data selector 28c. Note that this a = d also corresponds to each of a = d in the right column of Table 1, where a has data indicating 0, and b has data indicating 0, that is, l
/4Sij+t, C has the upper 5 bits of SjJ+1, that is 1/2Slj+1, and d has the upper 5 bits of Slj+1.
Data indicating the sum of the data of the bit and the upper 4 bits, ie, 3/4 S ij or 1 is given.

The outputs A and B of the data selectors 28b and 28c are set to one of the inputs a to d by the signal Bi applied thereto, and when Bi is data indicating 0, the input a is set to the outputs A and B, When Bi is data indicating 1, the input is set to outputs A and B, and when Bi is data indicating 2, input C is set to outputs Δ and B, and Bi
When the data indicates 3, the input d becomes the outputs A and B. The values of Bi are shown in Table 1.

The adder 28d outputs data indicating the sum of the output A of the data selector 28b and the output B of the data selector 28c as variable image data Oik.

The selection data Bi of the data selectors 28b and 28c is previously read into the RAM 3 before image reading.

A sub-scanning direction variable magnification image data calculator (not shown).

Two sets of line buffers are serially connected to the input end of the arithmetic unit 80XB, and the outputs of these buffers are connected in parallel.
This is a configuration in which the oxn is operated manually.

Microprocessor 35 of this second embodiment (FIG. 2a)
The scaling processing control operation is almost the same as that of the first embodiment shown in FIG. tb and FIG. Instead of data Bi settings.

As shown in steps 41x to 50x shown in FIG. 2h, data Bi (from Table 1) for the variable-magnification image data calculation according to (2) is set. Namely.

The decimal number Ri calculated with each value of i is.

0≦Ri<1/8.1/8≦Ri<3/8.3/8≦R
i<5/8°578≦Ri<7/8. and 7/8≦
Ri (1), in steps 41x to 47
Check with x, and if 0≦Ri<1/8, set data indicating O in register Bi (42x), 1/8≦
Ri (when 3/8, set data indicating 1 in register Bi (44x), when 3/8≦Ri<5/8, set data indicating 2 in register Bi (46x),
When 578≦Ri<7/8, data indicating 3 is set in register Bi (48x).

When 778≦R1<1, round R1 up to 1.

Update the contents of register J to a number larger by 1 (49x),
Set O in register B1. Bi set in this way is set as 1 in RAM3 along with Δ1 as in the first embodiment.
! Two or two are thrown in. Other scaling control operations are the same as in the first embodiment, and during image reading, data B1 set in this way is read out from IIAM 3 together with Ai and given to data selectors 28b and 28c. As a result, the scaled image data Oi which is the output of the adder 28d
k is calculated using the above-mentioned equation (6).

The processing described above is the same for Ioy.

FIG. 2c shows a modification of the main scanning direction variable magnification image data calculator 80XB shown in FIG. 2a. In this example, ROM2
8g, Sij's O~63. Sij++ 0-63. 4 types of coefficient A shown in Table 1 and 4 types of coefficient B shown in Table 1
The variable-magnification image data Oik calculated using the above-mentioned equation (6) using the seeds as parameters is stored using those parameters as addresses. The read address of the ROM 28g is Sij+Sij output from the data selector 27.
+t and the coefficients A and B (Table 1) defined by B1 and identified by B1, and Sij.

Sij+t, variable-magnification image data Oi calculated using equation (6)
k is ROM28. , is read out from.

Eyus Example (Figures 3a and 3b) Figure 3a shows the main parts of the third embodiment that are mainly different from the first embodiment, and the processing control operation is different from the first embodiment. Only the portion is shown in Fig. 3b.In this third embodiment, the main scanning magnification calculation unit 28 includes a main scanning direction magnification image data calculation unit goxc and a main scanning direction MTF correction calculation unit 110XA shown in Fig. 1d. The main scanning direction MTF correction calculator 110XC (not shown) has the same configuration as that of Two line buffers (not shown) that store image data for lines.

80X[l and a sub-scanning direction magnification computing unit consisting of the same operation 'rt (not shown); and line roses shown in FIG. 1e: 7781Y, 82'/and YMFT computing unit 10
It is composed of a sub-scanning direction MTF correction calculator (not shown) having the same configuration and structure as the 0Y(7) combination. To summarize, the third embodiment differs from the first embodiment only in the scaling processing arithmetic unit. Therefore, the scaling processing arithmetic unit of the third embodiment will be described in detail here.

In FIG. 3a, the main scanning direction variable magnification image data calculator 8
0XC calculates the variable-magnification image data Oik in the above-mentioned step (2).

Also, the data obtained by multiplying each of the four types of coefficients A in Table 2 by the original image data 5ij-1 is sent to the data selector 52, and the data obtained by multiplying each of the four types of coefficients A in Table 2 and the original image data are sent to the data selector 52. The data multiplied by S1j is sent to the data selector 53,
Each of the four types of coefficients C in Table 2 and the original image data Sjj
The data multiplied by
The data multiplied by j+2 is given to the data selector 55, and each of the data selectors 52 to 55 is specified by data Bi (Table 2). Data indicating values calculated using one type of coefficients Δ to D (each of 4 types: Table 2) is output, and the sum of these is outputted from the adder 5G as n image data Oik. .

Note that the complementer 57 is for converting subtraction data (-1/8) into addition data (converting subtraction to addition).

The outputs A-D of the data selectors 52-55 are
Depending on the signal Bi that is received, one of the inputs a and d is selected, and when Bi is data indicating 0, input a is set as output A-D, and when B1 is data indicating 1, the input is output. A-D, and when B1 is data indicating 2, input C is set as outputs A-D, and when Bi is data indicating 3-, input d is set as output A-D.

The value of Bi is shown in Table 2.

The adder 56 selects the outputs A to D of the data selectors 52 to 55.
The data indicating the sum of the images is output as the variable-magnification image data Oik.

The selected data B of data selectors 52 to 55 is stored in RAM3.
This is pre-loaded before one image is read.

Microprocessor 35 of this third embodiment (Figure 3a)
The scaling processing control operation of is almost the same as that of the first embodiment shown in FIGS. 1b and 1c, except that steps 15x to 17x in FIG. Instead of data Bi settings.

As shown in steps 41x to 50x shown in FIG. 3b, data Bi (those in Table 2) for the variable-magnification image data calculation according to (2) is set. Namely.

The decimal number Ri calculated with each value of i is.

0≦Ri<1/4. l/4≦Ri<1/2.1/2≦
Ri<3/4°374≦Ri<7/8. and 718
≦Ri (1), in steps 41x to 4
Check it out with 7x.

When 0≦Ri<1/4, set data indicating 0 in register B i (42x), and when 1/4≦Ri<1/2, set data indicating 1 in register B144x)
).

When 1/2≦Ri<3/4, set data indicating 2 in register Bi (46 x), 3/4≦Ri<7/
When it is 8, data indicating 3 is set in register Bi (48 x ). 778≦Ri (when l, R1
Round up to 1 and update the contents of register j to a number 1 larger (49x).

Set O in register Bi. Bi set in this way is stored in RAM3 along with Δ1, as in the first embodiment.
! ! - be included.

The other magnification processing control operations are the same as those in the first embodiment, and while reading one image, the data Di set in this way is
The data is read out from the RAM 3 and sent to the data selector 52.
~55 is given. As a result, the variable-magnification image data Oik, which is the output of the adder 56, is approximately +'+f (7
) is calculated using the formula. Similar processing is performed in the sub-scanning direction as well.

FIG. 3c shows a modification of the arithmetic unit aoxc shown in FIG. 3a. In this example, the ROM 63 stores 0 to 5ij-1.
63. S ij 0-63. Sij and 1's θ~63.
Sijya, O~63. Four types of coefficient A and four types of coefficient B shown in Table 2.

The variable-magnification image data Oik calculated using the above-mentioned equation (7) using four types of coefficients C and four types of coefficients as parameters is stored with these parameters as addresses. R
The OM63 read address is the data selector 27
5ij-1* 5ljtSlj+I output from
e The coefficient A-D (Table 1) determined by SIJ Y2 and Bi, and specified by Bi, and 5iJ-1+SiJ, S
At lj+lr5Ij-+-2, the variable-magnification image data Oik calculated using equation (7) is read out from the ROM 63.

Fourth Embodiment (FIG. 4) FIG. 4 shows only the constituent parts of the fourth embodiment that are different from the first embodiment. This fourth embodiment is characterized by sampling circuits 64 and 65.

The other parts are the same as the first embodiment, and the parts other than the sampling circuits 64*65 may be the same as the second and third embodiments.

In the sampling circuit 64 shown in FIG. 4, when RAM1 is designated for writing (a=H, b=L), AND gates 68 and 69 are off, and
is on, the address counter 38 is set to DCLK.
to count up. That is, each time one pulse of DCI, K arrives, original image data is read into nAMl.

When RAM1 is specified for reading (a-L, b=
II), the AND gate 67 is off and the reduction (d
= 1-1), the AND gate 68 is also off, and corresponding to the data Ai, when it is 1-1, DCLK is applied, when Al is L, 2DCLK is applied, and the AND gate 71 or 72 and the OR gate 70 and It is applied to the counter through an AND gate 69 and an OR gate 66. When expanding (d = L), AND gate 6
9 is off and Ai is high, DCLK is applied to counter 38 through AND gate 68 and through OR gate 66, and when Ai is low, no clock is provided to counter 38.

Sampling circuit 65 also has the same configuration as 64, but the
; Swap J-a and b and make AND gates 74 and 75
and 76. This is because when RAMI is written, RAM2 is read, and when RAMI is read, l(A M 2 is written).

Due to the configuration and operation of the sampling circuits 64 and 65 described above, the fourth embodiment also has the same structure as that of the first embodiment (1a
In the same manner as in Figure), write RAMI,2.

Read sampling of RAMs l and 2 is performed. That is, in the first embodiment, the up/down counter 3
9.44 and adder 37.42, the sampling of the original image data is performed one by one at the time of reduction by counting DCLK twice and advancing the address by 2 for each pulse of DCLK. However, in the fourth embodiment, in this case, 2
1) Give CL to the address counter and set DCLK to 1.
When a pulse is generated, the address counter is incremented by 2, and the address is advanced by 2 for each pulse of DCl.

Fifth embodiment (Fig. 3d) FIG. 3d shows the main part of the fifth embodiment of the present invention.

Figure 3d shows only the parts that differ from Figure 3a. This fifth
The embodiment is also a modification of the third embodiment, and the above-mentioned (11th)
), the variable-magnification image data calculation and MTF correction calculation in the main scanning direction are performed simultaneously, and the variable-magnification image data calculation and MTF correction calculation in the sub-scanning direction are also performed simultaneously.

First, explaining the arithmetic processing in the main scanning direction, in this fifth embodiment, 1912 worth of original image data is read and written into each of the RAMI and IIAM 2 in order to reduce the required memory capacity l. Depending on these, adjacent image data can be processed simultaneously in parallel! ), the arithmetic unit 28 has four latches 25 . .about.254, thereby obtaining image data of five adjacent pixels, and combining these image data.

The coefficients shown in Table 3 are used to obtain data that has been scaled and MTF corrected.

The data selector 111 is E-5ij in equation (11).
The data selector 112 outputs one of four values obtained by multiplying -2 by the coefficient E in Table 3, and the data selector 112 calculates the value of Equation (11).

The data selector 113 outputs one of four values obtained by multiplying A-5ij-1 by the coefficient A in Table 3, and the data selector 113 multiplies B-3ij in equation (11) by the coefficient B in Table 3. The data selector 114 outputs one of the four values obtained by multiplying C′Sjj+1 in equation (11) by the coefficient C in Table 3. , the data selector 115 selects the (11th
), one of the four values obtained by multiplying D-3IJ-+-2 by the coefficient in Table 3 is output. Which of the four types is output is determined by the data Bi that the RAM 4 provides to the data selectors 111-115. Data selector 111
The outputs of ~115 are given to the adder 11G, and the addition Ta
116 is the data Bi of the calculated value (4 interpolations of case a = d) obtained by substituting the coefficients in Table 3 into equation (11).
Outputs lMik specified by .

As already explained in relation to equation (11) and Table 3, this output Mik is subjected to magnification processing in the main scanning direction, and is also calculated by using R as a variable and providing the optimum MTF correction at each point of R. It is folded in.

Sub-scan magnification calculator 29 (not shown) of this fifth embodiment
is the latch 2 of the main scanning magnification calculator 28 shown in FIG. 3d.
Each of 51 to 254 is replaced with a line buffer memory.

The other configurations of the fifth embodiment are the same as those of the third embodiment described above. The scaling processing operation is similar to that of the third embodiment described above, but steps 51x to 57x shown in FIG. 1c are omitted.

In the fifth embodiment, since the scaling processing calculation and the MTF correction calculation are combined into the same calculation formula, the hardware related to the calculation is simpler than when they are calculated separately.
Furthermore, the number of calculation steps is small.

■Effects As described above, in the present invention, the designated magnification R of image data is
Since the MTF correction calculation corresponding to x and Ry is performed, image deterioration due to scaling processing is reduced. In addition, the variable-magnification image data calculation in the main scanning direction and the MTF correction calculation in the main-scanning direction are executed as a pair, and the variable-magnification image data calculation in the sub-scanning direction is performed, and the MTF correction calculation in the sub-scanning direction is performed as a pair. Therefore, even if the magnification ratio Rx in the main scanning direction and the scaling ratio Ry in the sub-scanning direction are different, the optimal MTF correction is performed in both the main scanning direction and the sub-scanning direction, and the image is Overall image quality deterioration due to zooming is reduced.

[Brief explanation of drawings]

FIG. 1a is a block diagram showing the configuration of a first embodiment of the present invention. FIGS. 1b and 1c are flowcharts showing the magnification change processing control operation of the microprocessor 35 shown in FIG. 1a. FIG. 1d is a block diagram showing the configuration of the main scanning magnification calculator 28 shown in FIG. 1a. FIG. 1e is a block diagram showing the configuration of the sub-scanning magnification calculator 29 shown in FIG. 1a. FIG. 2a is a block diagram showing main parts of a second embodiment of the present invention. FIG. 2b is a flowchart showing part of the magnification changing control operation of the microprocessor 35 shown in FIG. 2a. FIG. 2c is a block diagram showing a modification of the arithmetic unit 80XB shown in FIG. 2a. FIG. 3a is a block diagram showing the main parts of a third embodiment of the present invention. FIG. 3b is a flowchart showing part of the magnification changing control operation of the microprocessor 35 shown in FIG. 3a. FIG. 3c is a block diagram showing a modification of the arithmetic unit 80XC shown in FIG. 3a. FIG. 3d is a block diagram showing essential parts of a fifth embodiment of the present invention. FIG. 4 is a block diagram showing the main parts of a fourth embodiment of the present invention. FIG. 5 is a graph showing the values of the interpolation function used in the cubic function convolution method for calculating scaled image data, and the horizontal axis is the deviation of the sampling position assigned to the scaled image data with respect to the sampling position of the original image data. The vertical axis shows the value of the interpolation function. FIG. 6 shows data Y, which is the image reading output of the scanner SCI+ shown in FIG. 1a, and the synchronization clock LS'/NC. 5 is a time chart showing the relationship between DCLK and data Z that is the output of the latch 25. FIG. FIG. 7 shows the line buffer memory RAM shown in FIG. 1a.
3 is a time chart showing the relationship between write data and read data of I and II AM2 and line synchronization pulse LSYNC. FIG. 8 is a perspective view showing the appearance of a conventional image reading device. FIG. 9 is a side view showing the main mechanical components of one conventional image reading device. FIG. 10 is a side view showing the main mechanical component A of another conventional image reading device. FIG. 11 is a plan view showing the image data distribution in memory when one page of original image data is stored in memory for image data scaling using a conventional electrical method. . FIG. 12 is a plan view showing the relationship between the sampling position of JJX image data and the sampling position of variable-magnification image data when the variable-magnification image data is calculated by the linear distribution method of distance between adjacent pixels. FIG. 13a is a plan view showing the distribution of MTFli positive correction coefficients. FIG. 13b is a plan view showing the distribution of correction pixels in MTF correction and pixels referred to for correction. FIGS. 14a, 14b, 14c, and 14d are plan views showing the distribution of 1MTF correction coefficients. FIG. 15 is a graph showing the frequency response of the scanner SCR shown in FIG. 1a. FIG. 16 is a graph showing the scaling calculation interpolation coefficient with MTF correction taken into consideration. 1 Two-stroke reading device 2: Contact glass plate 3: Original pressure plate 4: Operation unit 5: Fluorescent lamp 6: Self-cleaning lens 7: Image sensor 8: Reflected light 9: Carriage 11 to 13; Reflected light 14: Lens
SCR: Scanner 28: Main scanning magnification calculator 2
9; Sub-scanning magnification calculator OOC: Original 35: Microprocessor (1st, 2nd calculation means, 1st
゜Second sampling position designation means) 64.65: Sampling circuit (first sampling means) 65V Two sampling circuit (second sampling means) 80XA: Data selector (first variable magnification image data setting means) 80V: Variable magnification calculator (Second scaling image data setting means) 1
00XA: Main scanning direction MTF calculation C (main scanning direction MTF calculation
TF correction means) toov: TF calculation unit in the sub-scanning direction (M in the sub-scanning direction
TF correction means) 80XB, 80XC: Magnification calculation unit (first magnification image data setting means) 28 in Fig. 3d = main scanning main scanning wave calculation 8: ((first magnification image data setting means, main scanning direction MTF correction means) 2nd b
Illustration table 3b ■ 4ax

Claims (8)

[Claims] (1) A first calculation means for calculating original image data sampling position information for creating variable-magnification image data corresponding to a specified magnification Rx in the main scanning direction; A variable-magnification image corresponding to a specified magnification Ry in the sub-scanning direction. A second calculation means for calculating original image data sampling position information for data creation; a specified sampling position x of the original image data based on the original image data sampling position information calculated by the first calculation means;
a first sampling position specifying means for specifying; a sampling specified position y of the original image data based on the original image data sampling position information calculated by the second calculation means;
a second sampling position specifying means for specifying; a first sampling means for extracting the original image data at the specified position x; a second sampling means for extracting the original image data at the specified position y; A first variable-magnification image data setting means for determining variable-magnification image data corresponding to the image data; a second variable-magnification image data setting means for determining variable-magnification image data corresponding to the original image data extracted by the second sampling means; specified magnification Main scanning direction MTF associated with Rx setting range
Main scanning direction MTF correction means that has correction calculation data and performs MTF correction on the image data after or before scaling in the main scanning direction based on the correction calculation data; A scaling processing device for image data, comprising: a sub-scanning direction MTF correction means that has direction MTF correction calculation data and performs MTF correction on image data after or before scaling in the sub-scanning direction based on the data. (2) The main scanning direction and sub-scanning direction MTF correction means each use correction calculation data corresponding to the magnification area obtained by subdividing the setting range, and the number of correction calculation means corresponds to the number of subdivisions, and the correction calculation Specify one of the means as magnification Rx, Ry
2. The image data scaling processing apparatus according to claim 1, further comprising a selection means for specifying the selected data according to the MTF correction data and obtaining the output as MTF correction data. (3) The first and second calculation means are each 100i/
[Specified magnification R (%)] = Ji + Ri, i is an integer, 0≦R
i<1, Ji is an integer, and the first and second sampling position specifying means are respectively,
While changing i by 1 in synchronization with the data clock and line clock that define the pixel unit of the original image data, R<
In the case of 100, Ji-Ji-1=2 specifies the specified sampling position x, y of the original image data to a number larger by 2, and Ji-Ji_-_1=1 specifies the specified position x, y to a larger number by 1. , R≧100
In the case of , Ji-Ji_-_1=I specifies the positions x and y to be 1 larger, and Ji-Ji_-_1=0 specifies the positions x and y as the same numbers; the first and second Each of the sampling means counts the data clock and the line clock to extract the original image data at the specified positions x and y and one or more image data adjacent thereto; The double image data setting means are synchronized with the data clock and line clock, respectively, and
The variable-magnification image data at position i is determined by the correlation of the original image data at the designated positions x and y and one or more adjacent original image data; as described in claim (1) above. Image data scaling processing device. (4) The first and second variable-magnification image data setting means respectively set variable-magnification image data as original image data at specified positions x and y when Ri≦0.5, and set variable-magnification image data as original image data at designated positions x and y when Ri>0.5. The image data scaling processing device according to claim 3, wherein the image data is original image data at positions x+1 and y+1. (5) The first and second scaled image data setting means each add a weight of Ri to the original image data at positions x and y, and add a weight of 1-Ri to the original image data at positions x+1 and y+1, respectively. The image data scaling processing device according to claim (3), wherein: is the scaling image data. (6) The first and second variable-magnification image data setting means each set the variable-magnification image data to Ri, original image data at positions x and y, and three original image data before and after the three as parameters. The image data scaling processing apparatus according to claim (3), which is obtained by a next function convolution formula. (7) The first sampling means is: Buffer memory means for storing one line of original image data; Means for alternately setting the buffer memory means for writing/reading; Address giving the writing/reading position to the buffer memory means Counting means; when writing to the buffer memory means, the data clock DCLK is applied as a count pulse to the address counting means; when reading from the memory means, i is changed by 1 in synchronization with the data clock DCLK, and When R<100, one of the count pulse 2DCLK and the data clock DCLK having twice the frequency of the data clock DCLK corresponding to Ai is applied as a count pulse to the address counting means, and R≧1.
00, the data clock DCLK corresponds to Ai.
Claims (3) and (4) include: sampling position designating means for designating the reading position x of the original image data by applying/cutting off the voltage to the address counting means;
), (5), or (6). (8) The first sampling means is: Buffer memory means for storing one line of original image data: Means for alternately setting the buffer memory means for writing/reading; Address counting means; Up/down counting means; Address counting means addition means for supplying the sum of the count data of the up/down count means and the count data of the up/down count means to the buffer memory means as address data; when writing to the buffer memory means, supplying the data clock DCLK as a count pulse to the address count means; When reading from the buffer memory means, the data clock D
Change i by 1 in synchronization with CLK, and R<10
In the case of 0, the up/down counting means is instructed to go up, the data clock DCLK is given as a count pulse to the address counting means, and DCLK is applied/cut off to the up/down counting means in accordance with Ai, and R≧
If the value is 100, the up/down count means is instructed to down and the data clock DCLK is sent to the address count means.
and the data clock DCLK corresponding to Ai.
Sampling position specifying means for specifying the read position x of the original image data by applying/cutting off the voltage to the up/down count means;
The image data scaling processing device according to item 4), item (5), or item (6).