JPS60116274A - Correcting device of picture signal - Google Patents

Abstract

PURPOSE:To prevent occurrence of unevenness in density with a plane scanning type phototelegraphic device using an oscillating mirror, by changing each temporal position of picture element data inversely proportional to the change in the scanning speed of a recording optical point at every moment. CONSTITUTION:Correction data for every picture element data which offset the positional error of recording optical points corresponding to each picture element data on one scanning line are stored in advance in an ROM6. Then, when picture element data for each scanning line stored in a storage section 2 are read out, reading out timing of each corresponding picture data is controlled with each correction data. Therefore, temporal position of each picture element data on a recorded picture changes inversely proportional to the change in the scanning speed of recording optical points at every moment. As a result, occurrence of uneven density caused by the non-uniform property in velocity of the recording optical points can be prevented.

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] The present invention relates to an image signal correction device, and in particular, to a plane scanning photoelectric transmitter/receiver device using a vibrating mirror. The present invention relates to an image signal correction device that corrects distortion of recorded images.

[Prior art]

In general, in a thousand-face scanning photoelectric transmission device that uses a vibrating mirror, if the vibration speed of the vibrating mirror is constant during scanning, the scanning speed of the recording light spot that scans the photosensitive recording medium is slow in the center. It is often said that the speed is faster in the peripheral areas. On the other hand, if all pixel data for each pixel read from the original image is recorded as it is by constant speed scanning, the peripheral area in the main scanning direction of the recorded image will be expanded by D' compared to the central area due to the above-mentioned characteristics.
generates distortion.

The image signal correction device in a conventional flat scanning type photographic transmission device using a vibrating mirror adds data to correct the above-mentioned non-uniform velocity to the driving power of the vibrating mirror, and changes the vibration speed of the vibrating mirror during scanning. It is controlled so that the scanning speed of the recording light spot is corrected to be constant.

However, in the conventional method described above, when the vibration speed of the vibrating mirror increases, it becomes difficult to physically control the variable speed.
+ Since complete correction is impossible, there is a drawback that density unevenness parallel to the sub-scanning direction occurs in the recorded image in the portion where the correction is incomplete.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an image number correction device that can prevent density unevenness by changing the temporal position of each pixel data in inverse proportion to minute changes in the scanning speed of a recording light spot. It is in.

[Structure of the invention]

The image signal correction device of the present invention includes a planar scanning type recording optical system including a light source and a vibrating mirror, and a system that reads out pixel data corresponding to a preceding scanning line while writing pixel data corresponding to a subsequent scanning line. a first storage means having a capacity for storing the pixel data corresponding to two scan wins; and a first storage means having a capacity for storing the pixel data corresponding to two scan wins, respectively corresponding to the pixel data due to non-uniform velocity in the scanning section of the recording light spot from the recording optical system. The pixel data 71-? The pixel data storage device includes a second storage means that stores in advance correction data r for each pixel that controls the readout timing of the pixel data, and outputs the correction data when the corresponding one pixel data is read out.

[Explanation of Examples]

The present invention stores correction data for each pixel data in advance in the second storage means, which cancels the position error of the recording light spot corresponding to each pixel data in one scanning line, which is caused by a speed change in the scanning section of the recording light spot. When reading out the pixel data for each scanning arm stored in the first storage means, by controlling the readout timing for each corresponding pixel data using each correction data, it is possible to read out the pixel data in the recorded image. This invention aims to realize an image signal correction device that corrects the position of each data to prevent density unevenness from occurring in a recorded image.

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. It includes a counter 4, a read counter 5, a ROM 6 as a second storage means, a write/read control circuit 7, and a D/A conversion circuit 8.

In FIG. 1, pixel data DA is a series of input signals having voltage values corresponding to respective pixel densities, which are supplied to an A/D conversion circuit l and converted into multivalued digital pixel data according to each voltage value. converted.

The storage unit 2 includes switchers 21, 23, 24, and 26, and storage circuits 22 and 25. Each of the memory circuits 22 and 25 has a capacity capable of storing digital pixel data for one scanning line, and writes and reads alternately such that one is writing while the other is reading.

The write/read control circuit 7 supplies the write/read instruction signal E and the order to the switch 21.23 and the switch 24.26 each time the phase signal P rises.

The write/read instruction No. 1 E and the hill are signals that become "low" when one is "no", and the other is "low", and the memory circuits 22 and 2
5 is the write/read instruction signal E and 100 is written when it is "no/y"; is it read when it is "low"? Give instructions.

The synchronization clock 81 has a period n times the pixel period.

A pixel clock S2 whose frequency has been divided by l/n by a frequency divider 3 is supplied to a write counter 4.

The write/read control circuit 7 performs “
A counter activation signal F which becomes "high" and becomes "low" every time the next inverted phase signal P falls is generated and supplied to the write counter 4 and read counter 5.

The 1"-included counter 4 counts the pixel clock S2 during the period when the counter activation signal F is "no," and reads the write address W E
When e occurs and becomes "low", it is set to the initial value.

During the period when the finger signal E is “No・I”, the switch 21
Digital pixel data corresponding to the m-th scanning line is supplied to the storage circuit 22. On the other hand, the write address W'E is supplied from the switch 23 to the memory circuit 22, and the di/kle pixel data corresponding to the m-th scanning line is written into the memory circuit 22 according to the instruction of the write address Wg. Ru.

The write/read instruction signal E becomes "high" with the phase signal P for the (m+1)th scanning line, and the switchers 24 and 26
becomes a convolution state, and the memory circuit 25 stores (
Dec/cle pixel data corresponding to the (m+1)th scanning line is written.

On the other hand, while writing to the digital pixel data storage circuit 22 corresponding to the m-th scan +m, the write/read instruction signal E is "low" and the switches 24 and 26 are in the read state.

The read counter 5 counts the synchronous clock 81 while the counter activation signal F is "high", generates an address, and reads the ROM.
6, and when it goes low, it is set to the initial value.

The read address for each digital pixel data is adjusted in advance by canceling out the difference in position tF of the recording light spot corresponding to each digital pixel data, which is caused by a change in the scanning speed in the scanning part of the recording light spot. Each correction data for controlling the timing of occurrence of RD is stored.

The method of creating the correction data is as follows: For example, a vibrating mirror is driven without correction, and a constant period pulse signal is recorded on a photosensitive recording medium. By measuring the pulse interval on the recording surface, a change in the scanning speed of the recording light spot is determined, and a data counter is used to specify the number of addresses from the readout counter 5 for each corresponding digital pixel data so as to make the change zero. Create and RO
Write to M6.

Now, digital pixel data corresponding to each pixel from the O#th to the Hth housing is arranged in the main scanning direction,
The correction data for the 0th di/kle pixel data is (
n-3), the address of the read counter 5 (that is, the number of periodic clocks SIQ) is (n-3) after the read address RD for the 0th disk/cle pixel data is generated.
3), the read address RD for the first digital pixel data is generated from the ROM 6.

The correction data for the digital pixel data of the first fragrance is (
n-2) After the readout address for the first digital pixel data, when the readout address 5 is (n-2), the readout address RD for the second digital pixel data is Occur. below,
Similarly, read addresses RD are generated sequentially in accordance with the correction data in the H@th digital pixel data translation.

” That is, the deviation value of the number of addresses with respect to n becomes the correction value of the temporal position for each di/cle pixel data.

Since the memory circuit 25 stores the D/C pixel data corresponding to the (m-t)th scanning line, it is sequentially read out according to the number of readout atons supplied to the D/A. The signal is supplied to the conversion circuit 8.

The D/A conversion circuit 8 converts the multi-valued digital correction data into voltage values corresponding to respective values, outputs value-correct recording data DR, and supplies the data to a recording circuit (not shown) to record it on a photosensitive recording medium.

When the write/read instruction signal E becomes "low" in the next phase No. 100 P, the digital pixel data corresponding to the m-th scanning line stored in the storage circuit 22 is read out.

At the same time, (m+1
3-th disc/kle pixel data corresponding to the )th scanning line is written.

By repeating the above operations for each scanning line, one copy of the picture can be created and compiled.

Next, FIG. 2 is a block diagram of a readout circuit section showing another embodiment, and all circuit parts not shown in FIG. 2 are the same as those in FIG. 1.

In FIG. 2, the frequency division ratio data for the C1C12 lock Sl are stored in advance in the OM6' as temporal position correction data for each digital image cumulative data.

Now, at the rising edge of the inverted phase 1st signal T, the counter start signal F is applied.
becomes "high" and a read address RD for the 0th digital 111+i search data is generated from the read counter 5', the ml output address RD is supplied to the storage circuit 22 or 25 designated for reading, and at the same time, ROM
6'.

The OM 6' reads the division ratio data of the correction data for the 0th digital pixel data and supplies it to the frequency divider 10.

The frequency divider 10 is a counter that divides the frequency of the synchronous clock Ssk according to frequency division ratio data and supplies the read clock S3 to the read counter 5'.

The read counter 5' counts successive clocks 8sk, generates a successive address RD for the first digital pixel data, and supplies it to the storage circuit 22 or 25 and the ROM 6'.

Thereafter, in the same manner, for each n digital pixel data up to the H-th digital pixel data, a read address (LD) is generated and stored from the storage circuit 22 or 25 at the generation timing according to the division ratio data from the ROM 6'. At the same time, it instructs to read out the digital pixel data that has been
The signal is supplied to the ROM 6' and the corresponding division ratio data is read out.

As explained above, in this embodiment, pixel data is processed digitally, but by using an analog memory such as a COD memory in the storage circuit and controlling the readout timing with a voltage controlled oscillator, the pixel data is processed digitally. Good too.

〔Effect of the invention〕

As described above, the image signal correction device of the present invention has two types of storage means: the first storage means and the second storage means. In addition, correction data for each pixel data is stored in advance to offset the position f error of the recording light spot corresponding to each pixel data in one scanning line, and the readout timing for each pixel data stored for each scanning line is adjusted. By controlling with the corresponding correction data, the temporal position of each pixel data in the recorded image changes in inverse proportion to the change in the scanning speed of the recording light spot, causing density unevenness in the recorded image. This has the effect of improving image quality because it can prevent '.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the invention, and FIG. 2 is a block diagram of a readout circuit section showing another embodiment of the invention. In the figure, 2... storage section, 5.5'...
...Read counter, 6, 6'...ROM, 22
．． 25... Memory circuit, DA... Pixel data. Anko I Figure 2

Claims (1)

[Claims] A planar scanning type recording optical system equipped with a light source, a vibration ξ, and at least two scanning lines for reading out pixel data corresponding to a preceding scan while writing pixel data corresponding to a subsequent scanning scheme. a first storage means having a capacity to store the I[Itl elementary data; and the recording means corresponding to the data of both systems due to the non-uniform velocity in the traveling part of the recording light spot from the recording optical system. In order to cancel the positional error of each light spot, correction data for controlling the readout timing of each of the pixel data in the first storage means is stored in advance, and each correction data is used to control the readout timing of each of the pixel data in the first storage means. biIIIii4Fa (
Tsukasa Toiman (1st Kirimicho 1W)