KR960007916B1 - Image compensation apparatus and method of facsimile - Google Patents

Abstract

The system compensates the resolution of facsimile image by changing amplification at both ends of image. It includes a central processing unit(CPU)(10), a RAM(20), a multiplexor(30), an amplifier(40), 1st counter(50) and 2nd counter(60). A line of white data read on the control of CPU(10) is divided into several partitions. For each partition, the multiplexor(30) assigns different amplification value. The system does not use an LED array as a source of light and a compensation board in the optical circuit. These characteristics enable the system to minimize and to simplify window pulse signal for its process and volume.

Description

Facsimile Image Correction Device and Correction Method

1 is a structural diagram for explaining an image correction method using a conventional shading plate,

(a) is an optical system configuration,

(b) is a shading plate.

2 is a block diagram of an image correction apparatus using a conventional digital-to-analog converter.

3 is a block diagram of an image correction apparatus using a conventional image correction IC.

4 is a block diagram of an image correction apparatus of a facsimile of the present invention.

5 is an actual image correction interval state diagram of the present invention.

6 is a sub-input / output timing diagram of FIG. 4.

7 is an operation flowchart showing the image correction method of the present invention.

* Explanation of symbols for main parts of the drawings

5, 10: central processing unit 7, 20: RAM

30: multiplexer 40: amplifier

50, 60: counter

The present invention relates to a facsimile image correction device and a correction method in which the facsimile image output is adjusted to improve the output of the portion by adjusting the amplification degree at both ends of the image to compensate for the unevenness due to the characteristics of the optical system.

In general, the facsimile output of the image is not flat due to the characteristics of the optical system. In order to correct this, a shading plate, a digital / analog converter, or an image correction IC is conventionally used.

First, the method of using the shading plate is a light source (2) first to third mirrors (MIR1 to MIR3) for reading the image information on the original (1) as an electrical signal, as shown in (a) of FIG. In the optical system composed of the lens 3, the facsimile 4 as shown in FIG. 1 (b) is inserted between the lens 3 and the third mirror MIR3.

Then, only the shaded portion of the shading plate 4 passes, so that a large amount of light passes through both sides and a small amount of light passes through the middle portion, thereby making the image output relatively flat.

However, this method does not allow the light source to be an LED array, and the problem arises that the light system becomes large and the work becomes complicated.

Second, the method using the digital / analog converter reads the white portion of the roller or white line before reading the original and inputs it into the ram 7 as a reference line for white, as shown in FIG. After this, the original is read and processed so that each pixel can be compensated.

That is, the central processing unit 5 increases the output current by increasing the data value of the digital / analog converter 6 at both ends of the image, and lowers the data value of the digital / analog converter 6 at the middle portion. The current is less.

As such, when compensating image output for each pixel, the central processing unit 5 should have a high processing speed.

Therefore, if the speed of the central processing unit is slow, the above method cannot be applied, and there is a problem in that it must be dependent on the processing method of the software.

Third, a method of using an image correction IC requires an image correction IC 8, a RAM 7 for driving it, a timing control circuit 9, a ROM, and the like, as shown in FIG.

The image correction IC 8 stores the white reference line read before the original reading in the RAM 7, and then reads the original and the value read from the analog / digital converter when the original is read. ), The image output can be flattened by comparing the stored values and calculating and multiplying the amplification factor for each pixel.

However, such a method requires an image dedicated RAM, a timing control circuit, a ROM, and the like for driving the image correction IC, and has a problem of high price.

The present invention is to solve the above-mentioned problems, the object of the present invention is to use a light source as an LED array and to compensate for the image output without using a compensation plate on the optical path, the image of the facsimile to make the optical system smaller The present invention provides a calibration device and a calibration method.

It is another object of the present invention to provide a facsimile image correction apparatus and a correction method that can be applied even when the processing speed of the central processing unit is low and the circuit configuration and operation are simplified.

It is still another object of the present invention to provide a facsimile image correction apparatus and a correction method for arbitrarily setting a compensation value at a predetermined interval according to the characteristics of an optical system.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 4 through 7.

4 is a block diagram of a facsimile image correction apparatus of the present invention. As shown in FIG. 4, a central processing unit 10 for controlling the operation of the entire facsimile, such as accessing a RAM or controlling a multiplex, and a central processing unit. RAM 20 for storing a line of white data read under the control of (10) and the minimum value for each section based on the same, and outputting the stored contents, and different settings according to control signals of the central processing unit 10. A multiplexer 30 for selecting and outputting one of the amplification values, an amplifier 40 for amplifying by the amplification factor output from the multiplexer 30 to binarize the image signal output from the optical system, and one line of the image signal. A first counter 50 for dividing and counting a data clock and inputting pulses generated at predetermined intervals to the central processing unit 10; The second counter 60 is configured to count the data clock that is not input and control the first counter 50 not to output a pulse.

When the optical system is configured using the LED array having low luminous intensity, the present invention configured as described above should flatly compensate the A1 and A3 sections in which the optical system output does not appear flat as shown in FIG. 5.

For this purpose, the image output can be smoothly corrected by dividing the sections A1 and A3 into seven equal parts and amplifying the sections divided by seven equally while changing the amplification degree.

The image correction method of the present invention will be described based on the operation flowchart of FIG.

When power is supplied to the facsimile, the central processing unit 10 reads the white roller surface by the scanner, stores one line of the white data in the RAM 20, and stores one line stored at a reference value (assuming 5V in this case). The value minus the minute is calculated and stored in the RAM 20 again.

When the A1 section and the A3 section of FIG. 5 are divided into seven equal parts by the user or in the production assembly process, one of the equal sections is selected and set from a value between 0 and 64 bits.

This is intended to correspond to the characteristics of the optical system, respectively.

Assuming that each equal division is set to 32 bits, since the A1 interval is divided into seven equal parts, 7 × 32 = 224 bits of image are output, and then the A2 interval is reached. 1728-224 x 2 = 1280 bits, or 160 mm.

When the calculation is set and the interval value is determined, the CPU 10 calculates the last bit value of each interval from the value stored in the RAM 20 and stores the RAM in the RAM 20. If not set, the initial setting value is stored in the RAM 20.

Then, it is possible to calculate the amplification degree when each input value of the multiplexer 30 is selected according to the value, and if each amplification degree is calculated for the seven intervals, the first input value IN1 of the multiplexer 30 is selected. The amplification factor at the time is the largest, and the amplification factor at the time when the last input value IN8 is selected is the smallest.

When the image is transmitted in the transmission or coffee mode, the first counter 50 of FIG. 4 operates to provide a pulse to the central processing unit 10, and the central processing unit 10 sends a control signal to the multiplexer 30. Output so that the first input value IN1 is selected.

Here, the first counter 50 counts the data clock pulses as shown in (a) of FIG. 6 to generate pulses at predetermined intervals as shown in (b) of FIG. 6, wherein the period of the pulses is When the A1 section is divided into seven equals, it is equal to each divided section value.

The second counter 60 similarly counts the data clock pulses and outputs a high potential signal (see (c) of FIG. 6) to the first counter 50 in the A2 section where the optical system output is flat.

As shown in (d) of FIG. 6, the first counter 50 receiving the signal outputs the pulse to the CPU 10 only in the A1 section and the A3 section.

When the first pulse comes from the first counter 50, the CPU 10 selects and outputs the first input value IN1 of the multiplex 30, and at the same time, the timer TMR1 is set to an equally divided interval value. The amplifier 40 amplifies and outputs the image signal by the amplification factor set by the output value of the multiplexer 30.

When the timer TMR1 is turned off, the CPU 10 controls the second input value IN2 of the multiplexer 30 to be selected, and inputs the multiplexer 30 whenever the time set in the timer TMR1 elapses. The values IN3 to IN7 are sequentially selected so that the amplifier 40 amplifies the image signal in the A1 section at an amplification factor that is gradually decreased.

Next, the central processing unit 10 causes the last input value IN8 of the multiplexer 30 to be selected and operates the timer TMR2 so that the amplifier 40 is the smallest in the flat section A2 without compensation. The amplification rate is used to amplify the image signal.

When the timer TMR2 is turned off, the central processing unit 10 causes the input values IN7 to IN1 of the multiplexer 30 to be sequentially selected in turn each time the time set in the timer TMR1 elapses as described above. 40) amplifies the lower phase signal of the A3 section at an increasing amplification rate.

When the operation for compensating the image signal for one line read in this way is completed, the above-described operation is repeated until the reading is completed and then ends.

As described above, the present invention divides the intervals according to the characteristics of the optical system and sets the compensation value differently for each of the predetermined intervals, thereby compensating the image output even when the light source is used as the LED array and the compensation plate is not used on the optical path. The optical system can be miniaturized.

In addition, the circuit configuration and operation is simplified, thereby increasing productivity and lowering costs.

In particular, the conventional compensation type is determined internally, in the present invention can be compensated by arbitrarily setting the compensation value according to each optical system.

Claims (4)

A central processing unit 10 for controlling the operation of the facsimile appetizer such as accessing a RAM or controlling a multiplexer, a line of white data read under the control of the central processing unit 10, and a minimum value for each section based thereon RAM 20 for storing and outputting the stored contents, a multiplexer 30 for selecting and outputting one of different amplification values set according to the control signal of the central processing unit 10, and an image signal output from the optical system. An amplifier 40 for amplifying by the amplification factor output from the multiplexer 30 for binarization, and dividing one line of an image signal, counting a data clock, and inputting pulses generated at predetermined intervals to the central processing unit 10. The first counter 50 and the data clock inputted during the period where the image signal is flat and do not need compensation are counted so that the pulse is not output from the first counter 50. Is provided with a second counter (60). The apparatus of claim 1, wherein a plurality of amplification values input to the multiplexer (30) are arbitrarily set according to the characteristics of the optical system. A first process of setting intervals by dividing the actual image data of one line and calculating the last bit value of each interval, and each time divided into equal portions in the first compensation interval A1 when image reading starts, A second process of amplifying the image signal by selecting a reduced amplification factor, a third process of amplifying the image signal by selecting a smallest amplification factor in a flat section A2 that requires no compensation, and a later compensation period (A3) And a fourth step of amplifying the image signal by selecting an amplification factor that is increased slightly each time the sections divided into equal parts) are started. 4. The method of claim 3, wherein the first process includes reading a white roller surface when the power is turned on, and storing white data for one line, and subtracting the stored white data value from the reference value to store a subtracted value. Step 3, the third step of setting the sections by dividing the one line and assigning the number of bits for each divided section, and the last bit of each section in the stored actual image data value where the section value is determined in the third step And a fourth step of calculating and storing the value.