JPS63187965A - Color picture reading system - Google Patents

Abstract

PURPOSE:To increase the density of the picture elements of a color picture to threefold by obtaining picture data to be converted into printing data of one picture element by mutually overlapping and setting the groups of three color elements of one dimensional color sensor. CONSTITUTION:Four CCD sensors are arranged in a staggered form and in one line in the one-dimensional contact type color CCD sensor 1, and filters of R, G and B are sequentially generated in scan directions in one picture element of respective sensors. R, G and B signals from respective CCD sensors are transmitted to an analogue mutiplexer 2, where they are switched, and transmitted to a sample and hold circuit 3. The signals are then transmitted from the sample and hol circuit 3 to a color operation circuit 7 through a signal amplifier circuit 4, an AD converter 5 and a shading correction circuit 6. The color operation circuit 7 generates three colors of C, M and Y with multiplying R, G and B by a prescribed coefficient. Using overlapped adjacent picture element data as illustrated, the density of the picture elements three times as much as a reading density can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application iD) The present invention is a method for reading color images using a color sensor in which pixels for reading three colors (for example, R, G, 13) are sequentially arranged adjacent to each other. Regarding the method.

(Prior art) Color sensors used in color image human-powered devices include:
There is one in which pixels for reading three colors (for example, R, G, and B) are sequentially arranged. f In other words, one-dimensional close contact type C
In a CD color sensor, R, G, and B filters are sequentially deposited within one pixel, and data is basically output in the order of R-G-B in a norial manner. Then, i calculation processing is performed to convert this set of data into three colors used for printing.

(Problems to be Solved by the Invention) In this color calculation processing method, the density of image reading is equal to the density of pixels of the sensor. Therefore, the reading density cannot be higher than the pixel density of the available sensor (eg 16 lines/+++m).

In order to increase pixel density, conventional methods have been used to electrically process read image data.

SUMMARY OF THE INVENTION An object of the present invention is to provide a new color image reading method that reads images at a higher reading density than the sensor image density.

(Means for Solving the Problem) The inventor of the present invention thought that it is possible to increase the density by three times by performing this calculation between adjacent pixels, and arrived at the present invention. .

The color pixel reading system according to the present invention arranges sets of three types of elements that detect each of the three colors in a predetermined order, and arranges multiple sets of elements in one dimension. a color calculation processing device that primarily converts a set of three-color image data detected by the one-dimensional color sensor into one-pixel three-color print data for printing. In the color image reading method, a color calculation processing device includes a set of three color elements 5i (i=
1, 2. ...) to form a one-dimensional color sensor from a plurality of elements C. (j=1.2, ...) (Cj.

KoCj+1. Cj+2) set Pj (j=1.2...)
It is characterized by using

(Function) A set of three color elements of a one-dimensional color sensor is mutually ffi>
! By setting this value, the pixel density of a color image is increased by three times.

(Example) Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 shows a block diagram of the image reading circuit. The document is illuminated by a light source (fluorescent lamp, not shown), and image information of the reflected light is detected by an i-dimensional contact type color CCD sensor (1) and converted into an electrical quantity. This sensor (1)
is a combination of four COD sensors arranged in a row in a staggered manner, and each sensor has R (red),
G (green) and B (blue) filters are sequentially deposited in the scanning direction. (The shape of the pixel is not a square but a parallelogram to prevent the occurrence of moiré patterns.) Therefore, each CCD sensor has R, G
, B are sequentially sent to the analog multiplexer (2). The analog multiplexer (2) selects the signal output from the sensor on the 4th side, converts it into a -tree signal bus, and sends it to the sample and hold circuit (3). The sample and hold circuit (3) performs color separation on each of the R, G, and B signals. The next signal amplification circuit (4) performs differential amplification with respect to the black level while correcting the sensitivity of each signal R, G, and H. Each amplified signal is converted into an 8-bit digital value by an AD converter 5, and then sent to a shading correction circuit (
In step 6), shading correction is performed and sent to the color calculation circuit (7).

The color calculation circuit (7) receives the shading-corrected read image signal 11. Each of the G and H data is converted into print image data of C (green), 1M (magenta), and Y (yellow). In the color conversion process, print data r-R+g-G+b-B ・・・・・・■
Perform the following conversion. Since r, g, and b are certain constants and differ depending on each data of C9M and Y, ■
The equation can be rewritten as the following equation 0.

However, r, ~31g1-3. b1-3 are constants.

Therefore, in the color calculation process, each constant r, g.

After multiplying b by the read image data R, G, B, r・R
, g-G, and b-B are added.

In the color calculation process according to the present invention, as described below, the color pixel density is increased to three times by also calculating the sum of adjacent pixels. As shown in FIG. 1, the i-th pixel of the sensor is arranged in the order of Ri, Gi, and Bi. Assume that the 31st C value (C3,) is calculated from the i-th pixel data (Ri, Gi, Bi) using the following equation.

C31=r1・R1+g11IGi+b,・Bi...
...■At this time, the value of 3i+1st C (C3i+1
) is determined using the data of adjacent pixels.

C31+ 1=rI ° Ri+ l 10g plate ° G
i+bI °B i゛°°■Furthermore, the 31+2nd C value (C3i+2) is further determined using the data of the adjacent pixel.

c3i+2=rl' Ri+1 +g+ II G
i+ 1+b, 8 B l...■ Similar color calculation processing is performed for M and Y.

In this way, by performing color calculation processing using data of adjacent pixels, it is possible to obtain a pixel density three times the reading density.

FIG. 3 is a block diagram of the color calculation circuit (7).

The multiplication block (II) is a block that performs multiplication such as r-R, and its value is calculated by C, M,
The added values are sequentially sent to three addition blocks (+2.13°14) for Y, and each added value is sequentially sent to a data synthesis circuit (15). The operation of this circuit will be explained later in the timing chart (
This will be explained using Fig. 5).

FIG. 4 is a circuit diagram of a multiplication block (11) and an addition block (for example, 12) of I (I!IJ). The other two addition blocks are omitted for simplicity.

As shown in the flowchart of Fig. 5, the multiplication block (1
In 1), the input pixel data R, G, and B (8-bit digital data) read by the CCD sensor (1) are manually input to the parallel-to-serial conversion circuit (21) in parallel. , and in synchronization with the rising edge of clock CKl, which is triple the dot clock, R
, G, H serially to the multiplier (22).
Transferred as A. On the other hand, the selector circuit (23)
Three constants r, g, b (for example, in the case of C operation,
Select one of rl+ g++ bυ and add a multiplier (2
Send to 2). This selection is made by the select clock generation circuit (
Constant select clock CK2 generated in 24)
．． This is done in synchronization with the rising edge of CK3. thus,
r and R data, 1g and G data, and b and B data are respectively input to the multiplier (22) in synchronization. Therefore, the multiplier (22) receives r-R data and g-G data.

Multiplication of b-B data is performed in order, and the multiplied value is sent to the addition block via the latch circuit (2) in synchronization with the clock σ[n.

In the addition block, the selector circuit (34) periodically (once every third time) clears the added data DC to "φ" by the adder (31). In order to synchronize with the output DI3 from the latch (25), the data DC' is latched by a latch circuit (35) and fed back to the adder (31). Adder (31)
performs addition of the manual data DB from the multiplication block and the fed back DC', and adds the latch circuit (32
, 33) to output data DC.

The output DC of the latch circuit (32) is periodically cleared by the selector (34), and is latched by the latch circuit (33) in synchronization with the timing of the clearing.
■Achieves expression calculations. That is, the addition blocks are r-R+O, r-R+g-G.

While performing the addition r-R0g-G+b-B, r・R
Only data +g-G+b-B is output to the next processing block.

As shown in FIG. 3, the addition blocks shown on the right side of FIG. It is only the latch timing of the latch 34.

That is, as shown in the timing chart of FIG.
The selector circuits 34 in the addition blocks 1 to 3 periodically clear the output data DC from the adder 31 to "φ", but each block of blocks 1 to m has a different timing for clearing it to "φ" ( DC'), and the latch circuit 33 of each block latches DC in synchronization with the timing of clearing to "φ" in the selector 34 (see DD in FIG. 5). Therefore, the image data r-R□, g-cn output from the multiplication block.

If b-Bn is expressed as Rn', Gn', and Bn' for simplicity, then the addition block is Rn+ + G n+ +
B n', in ■, Rn-1-1'FuGn'10Bn', in ■, Rn+1°+G, +1°+ B n
', making it possible to triple the pixel density. Now, each block 1. I
If the outputs of l, II[ are DE, DF'n, DG, then D'
The output of each block is subjected to parallel run real conversion in the order of En, DFn, and DGn, and sent to the printer. thus,
In the color calculation processing circuit (7), when converting into print data C, M or Y, data with three times the reading pixel density is output.

In order to convert it into print data, the image input device that obtains the color information of the document repeats scanning three times for each print data C, M, and Y.

The output data (DH) of the color calculation circuit (7) is then converted in the image density conversion circuit (8) into a pixel density corresponding to the print dot density on the output side, that is, the printer side, and then sent to the printer. . Figure 7 shows the image density conversion circuit (
8), and FIG. 8 is a timing chart of its operation. This circuit (8) is used to convert the pixel density in the main scanning direction, and in the sub-scanning direction,
This can be addressed by changing the scanning speed of the optical system (the slower the scanning speed, the higher the density). Now, if the reading pixel density of C0D(1) is 16 lines/mm, the output (DI-1) of the data synthesis circuit has a density of 48 lines/mm.

The image density conversion clock generation circuit (41) generates a latch clock in the latch circuit (42) from the dot clock CK4 synchronized with this change in DH. The image density conversion data signal is normally set in accordance with the printing dot density on the output side, and is assumed to be 24 dots/mm. The image density conversion clock generation circuit (41) generates an r two-cycle clock (RCI()) specified by this image density conversion data signal from
send to The image density conversion instruction signal is a negative logic signal, and when this signal is "L", the clock RCK output from the image density conversion clock generation circuit (=il) is used as a latch clock, and the AND gate (42) and OR gate (4
3) to the latch circuit (44). On the other hand, when the image density conversion signal is "H", the A N D gate (42) and the OR gate (4
3) to the latch circuit. Therefore, when the image density conversion instruction signal is "Yes", the latch circuit (44) outputs pixel data of 48 lines/mm or less according to the number of printed dots on the output side, and when it is "H", the latch circuit (44) outputs data of pixels of 48 lines/mm or less according to the number of printed dots on the output side. Outputs data with a pixel density of 16 lines/mm.

Note that as the color calculation processing circuit, a conventional method shown in FIG. 9 may be used. That is, the color calculation circuit (7) is composed of a 3uI multiplier (51°52.53) and one adder (57).

FIG. 10 shows a timing chart of this circuit. In this color calculation processing circuit, multipliers are provided for each of r't, G, and I3 data, and the results are synchronized by latch circuits (54, 55, 56), respectively.

Then, the adder (57) adds three pieces of data a and Rl.
b-G and C-B are added in parallel, and the latch circuit (58) latches the addition result using a clock that is an inversion of the latch clock of the first latch circuit (54, 55, 56) to print data C, M. Or get Y. By thinning out the latch timing chart of the latch circuit (58), it becomes possible to change the magnification (7IX and 11 times). Obtain C, M, and Y data in three scans. This circuit is shown in Figure 3. Compared to the conventional method, this method is expensive because it uses 3 PL multipliers, which are quite expensive.

(Effects of the Invention) The reading density can be increased three times without changing the element density of the one-dimensional color sensor.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the correspondence between elements of a one-dimensional color sensor and pixels of printing. FIG. 2 is a block diagram of a color image reading device. FIG. 3 is a block diagram of the color calculation circuit. FIG. 4 is a circuit diagram of a part of the color calculation circuit. FIG. 5 is a timing chart of the multiplication block. FIG. 6 is a timing chart of the addition block. FIG. 7 is a circuit diagram of a latch synthesis circuit. FIG. 8 is a timing chart of the latch synthesis circuit. FIG. 9 is a block diagram of a modified embodiment of the color calculation circuit. FIG. 10 is a timing chart of the circuit of FIG. 9. Rn, Bn, Gn/dimensional color sensor image data, Cn...Cyan print data, 1...Color CCD sensor, 7...Color calculation circuit.

Claims (2)

[Claims] (1) Detection means for detecting color pixels using a one-dimensional color sensor in which sets of three types of elements each detecting three colors are arranged in a predetermined order, and plural sets of elements are arranged in one dimension; , and a color calculation processing device that primarily converts a set of three-color image data detected by this one-dimensional color sensor into one-pixel three-color print data for printing. In the processing device, a set of three color elements S_i (i=
A plurality of elements C_j (j=1, 2,...) constituting a one-dimensional color sensor as (C_j
, C_j+1, C_j+2) set P_j(j=1, 2,
A color image reading method characterized by using...). (2) In the color image reading method described in claim 1, the color calculation processing device converts a set of image data (R, G, B) detected by the element into a conversion coefficient (r , g, b) to convert the print data into one color D using the conversion formula D=r・R+g・G+b・B. A multiplication means for multiplying by the corresponding conversion coefficient (r, g or b), three addition means connected in parallel to the multiplication means for sequentially adding the multiplication values sent from the multiplication means, and serially connected from the detection means. Addition control means for causing the addition means to add 0 for every three pieces of multiplied data when image data is sent, and for making the timing of adding 0 different for each of the three addition means; and calculation by the addition means. 1. A color image reading method comprising an output means for holding printed print data and sending it to an output device.