JPH01290393A - Printer - Google Patents

Abstract

PURPOSE:To improve picture quality by applying A/D conversion to a video signal, storing the result and using a digital signal for Y/C separation. CONSTITUTION:A video signal inputted to a terminal 1 is converted into a digital signal by an A/D converter 2 and stored in the 1st field memory 3a or the 2nd field memory 3b. Signals of adjacent scanning lines to each other stored in the memories 3a, 3b are subtracted by an adder 29 and a color difference signal C is obtained through digital processing by passing the signal through a band pass filter 31 using the subcarrier as the center frequency. A luminance signal Y is obtained by subtracting 32 the color difference signal C from the signal stored in the memories 3a, 3b. The signals C, Y are demodulated into R, G, B signals by a color demodulation arithmetic unit 33 and inputted to a printer controller 13. A system controller 27 and a memory controller 4 apply changeover of switches 26, 30 and code sign control of the adder 29. The signal in the memories 3a, 3b is converted by a D/A converter 5 and displayed on the monitor 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a printing system for converting an analog video signal into a digital signal, digitally processing it, and printing it out. In particular, the present invention relates to the configuration of a printing device having memory means for storing the digital value n. In detail, the analog video signal is a composite signal, and by utilizing the fact that the correlation between fields or frames is large, Y/C
(Y: luminance signal, C: chroma signal) Separation is performed digitally, color demodulation is performed, and the printer prints out beautiful colors) Regarding the configuration of Hif7.

[Conventional technology]

An embodiment of a conventional storage device including memory means will be described with reference to FIG.

1 is a video signal input terminal, 2 is an A/D (analog-digital) converter, and 3 is a memory means for storing the digital amount of this A/D converter 2, and the capacity is for one screen field or frame. be.

4 is a memory control means for controlling the memory means 3;
It also emits a sampling clock for the D converter 2. 5 is a D/A (digital-analog) that converts the digital quantity read out in the scanning order of the memory means 3 into the original analog quantity;
It is a converter. Reference numeral 6 denotes a terminal that outputs the video signal converted into the original analog quantity to the monitor 7.

A color demodulating means 9 demodulates the video signal of the D/A converter 5 into three primary colors of R (red), G (green), and B (blue). Reference numeral 8 denotes a clock generating means for separating the synchronizing signal included in the video signal and generating locks necessary for various systems related to this synchronizing signal.

A switch 11 receives a signal and switches between R and 01B of the color demodulating means 9. This switch 11 is necessary because the printer of the printing device prints out three times sequentially and one on top of the other in order to simplify the sweat permeation mechanism. Reference numeral 12 denotes an A/D converter that performs digital F conversion on the video signal switched by the switch 11. 13 is A/D converter 1
This printer control means provides the output of 2 to the printer 14 at a predetermined timing while transmitting and receiving necessary signals. 15
is a system control means for controlling the printing apparatus system, which receives a predetermined clock from the clock generation means 8, sends a switch signal to the switch 11, sends and receives signals to and from the memory control means 4, and performs sampling to the A/D converter 12. The entire system is controlled by providing a clock and exchanging signals with the printer control means 13.

Reference numeral 16 represents an operation command to the printer device using keys or the like.

Note that the arrow lines in FIG. 8 represent the flow relationship and exchange relationship of signals or data.

As described above, in the printing apparatus according to the prior art, the memory means 3 is simply an image memory for one field or one frame, and it is necessary to convert it into digital data in order to print out the data stored in the memory means 3. The configuration is such that the printout image quality is impaired, such as using analog and color demodulation.

First, the NTSC signal of the video signal system related to the present invention and the color demodulating means 9 of FIG. 8 will be explained with reference to FIGS. 9 and 10.

In FIG. 9, the number of field scanning lines is 262.
FIG. 5 is a diagram showing a frame with 5 scanning lines and 525 scanning lines.

This is an interlace scanning method. The numbers in the figure indicate the time sequence of the scan lines.

FIG. 10 shows details of the color demodulating means 9 of the prior art. 5a
is the output signal of the D/A converter 5 in FIG. 20 is a delay line having an IH (H: horizontal scanning time) delay characteristic, and 21 is an analog adder with + and - attached to the arrow. Since the video signals at the same point on adjacent scanning lines are correlated, the chroma signals of the composite signal are almost the same and have an antiphase relationship, so the adder 21 extracts the chroma signals. , 22 is a BPF (bandpass filter), which removes the chroma signal of the adder 21 since it is a band signal of ±I MHz centered around the color subcarrier 3.58M+-1z. It is well known that a luminance signal Y can be obtained by adding the chroma signal that has passed through the nPF 22 and the signal 5a in an adder 23 while considering the sign. In addition to the color subcarrier 25 synchronized with the color burst signal and the detector 24 which detects the phase of the chroma signal described above, a detector 24 (not shown) obtains color difference signals R-Y and G-Y1B-Y. Adder 2
By adding Y obtained by the adder 23 in step 5, the color demodulated 3
Obtain primary color signals R, G, and B. The conventional color demodulation means described in FIG. 10 has a defect in that the constituent elements have temperature characteristics, and correct calculation results may not be obtained in some cases. There are also defects that exhibit aging characteristics.

[Problem to be solved by the invention]

However, with conventional technology, there are problems with deterioration of the S/N ratio due to many analog-to-digital conversion processes, and video signals that are close to still images have a large correlation between fields or frames. If used, a good Y/C separation characteristic could be obtained, but the memory means 3 is not fully utilized, resulting in a problem of poor printout image quality.

Therefore, the printing device of the present invention is intended to solve these problems.The purpose of the printing device is to use the memory means to perform digital Y/C separation and image processing, and then perform color demodulation to produce beautiful printouts. The purpose of the present invention is to provide a printing device for obtaining an image. Another object of the present invention is to provide a printing device that can perform appropriate image processing to obtain a beautiful printed image even when a Y/C separated video signal is input.

[Failure to solve the problem]

The printing apparatus of the present invention converts a video signal, which is a composite signal, into a digital quantity using an A/D converter, digitally processes it in a predetermined manner, and prints it out. A predetermined amount of storage capacity (for example, the capacity of one frame or two consecutive frames of an image)
memory means, a memory control means for controlling writing and readout of this memory means, data in a relationship where there is a high correlation between data in the memory means or between fields or frames between the data being inputted to the memory means. This Y/C separation means calculates good Y/C extra-compartmental characteristics
I;j [color demodulation means for performing color demodulation calculations using separated Y and C; printer control means for selectively supplying the color signals of this color demodulation means to the printer; and various components necessary for the above components or the system. It is composed of a clock generation means for generating a clock, and a system control means for receiving an operation command signal from an operation command means and controlling the component viewing means of the system, and it is possible to achieve nearly perfect Y/C separation in still images. and the luminance (g) stored in said memory means.
By providing the system control means with a process for emphasizing the color Y, it is possible to demodulate the emphasized color, thereby producing a beautiful printed image.

Furthermore, even if the input video signal is Y/C divided, it is once stored in the memory means in a predetermined manner and then subjected to appropriate processing and color demodulation to obtain a beautiful printed image.

[Effect]

According to the above configuration of the present invention, since video signals have a large correlation between pixels in the vertical direction, data can be held by providing a memory means having a memory capacity of one frame or two frames. Therefore, various processing steps can be applied. For example, complete Y/C separation is possible by utilizing the large correlation between fields and between frames. If the Y/C separated luminance signal Y and chroma signal C are stored in the memory means, a clear printed image can be obtained by subjecting the luminance signal Y to, for example, emphasis processing and guiding it to the color demodulation means.

Further, in the above configuration of the present invention, in the conventional analog signal, Y/C separation is performed by calculation using the scanning amount within the same field, but this method is also possible. This case is applied when the motion of the input image is relatively large.

However, the request for images to be printed out is for images that are close to static barking at least between frames.

Therefore, in most cases, Y/C separation between fields or frames will meet the requirements.

Furthermore, since all digital operations are performed after A/D conversion, it is possible to construct a good printing device that is independent of temperature and aging.

〔Example〕

FIG. 1 is a diagram showing a concrete block diagram of an embodiment of a printing apparatus according to the present invention. In the figure, the same numbers as in FIG. 8 indicate the same means or have the same meaning. Memory means 3a
and 3b represent the memory means 3 of FIG. 8 as 263H and 262.
It is shown divided into H capacities. Therefore, the memory means 3a and 3b are memory means corresponding to the first field and the second field indicated by solid lines and dotted lines in FIG. 9.

Here, after the memory control means 4 has taken in one frame, it prohibits the data from the A/D converter 2, and the memory means 3a and 3b hold the taken data. The memory control means 4 simultaneously calls the memory means 3a and 3b. Therefore, a switch 26 is provided to pass the call data in the memory means 3a during one field call. In the second field call, the data in the memory means 3b is passed. In this way, the data held in the memory means 3a and 3b can be correctly displayed on the monitor 7 using an interlace video signal.

28 in the dotted frame is a Y/C separation means, which is composed of digital adders 29, 13, PF31, an adder 32, and a switch 30. In the adder 29, shi and 壬 are written to mean that the relationship between the augend and the addition number changes depending on the target field.

Furthermore, since the nature of the video signal is that there is a large correlation with pixels that are closer to each other, the present invention uses field correlation. For example, Figure 9 00, 263.1, 264.2, 265...
..., and the adder 29 extracts the chroma signal C. It is known that the frequency characteristic of this adder 29 is a comb-shaped one whose period is the horizontal frequency rh as shown in a in FIG. The chroma band is ±IM) 1 z F degree centered on the subcarrier fsc.

Therefore, since the chroma signal output from the adder 29 may also include a reduced n-degree signal, it is passed through the BPF 31. An example of this BPF 31 is shown in FIG.

n P F 31 H A is a follow-up of B P F 40 and 41, and the one marked D is a delay element that delays the period of the sampling clock of A/D converter 2. D-F
It consists of F-type flip-flops.

36 and 38 are delay units of 2 units and 4 units, and 37 and 39 are adders. The characteristics of BPF configured in this way are the third
As shown in figure b, l3PF40 is a thin solid line, [1PF41
shows the characteristics as a dotted line, and the overall characteristics as a thick solid line. The characteristic including the adder 29 is shown as C in FIG. In this way, we obtain a pure chroma signal C. When this chroma signal is calculated with the composite signal passed through the switch 30 by considering the sign E2 in the adder 32, an accurate n-open signal Y is obtained.

The meanings of the symbols of the switch 30 and the adder 29 that change depending on the switch signal from the system control means 27, which has a different number from the system control means 15 in FIG. 8, are as follows.

The actual printout method is as shown in Figure 9, O line, 26
Complete the process by repeating each color three times in the order of 3 lines, 1 line, 264 lies, etc.

For example, when printing out the 0 line, Y/C separation is performed between the 0 line and the 234th line, and in order to extract a luminance signal, the switch 30 passes the composite signal of the 0 line.

When pre/dooring the 263 line, chroma signal extraction uses 0 rai/ and 263 rai/, but the switch 30 passes the 263 line as a composite signal. This is to similarly execute RAI/1 and 264, RHINO2 and 265, and so on.

The color demodulation calculator 33 calculates and extracts the Y/C accurately separated in this way using a predetermined calculation formula for the color difference signals R-Y, B-Y, and G-Y, and then adds Y to the three primary colors R1G5l3. emit a signal. The switch 34 selects one color in response to a switch signal (not shown) from the system control means 27 and sends it to the printer control 13.

Next 'B! Other embodiments of the present invention will be described with reference to FIG. S4, FIG. 5, and FIG. 6.

In FIG. 4, memories 36 and 37 have a frame memory capacity instead of the memory means 3a and 3b having a filled memory capacity in FIG. 1. The other components are the same as in FIG. 1 except that a switch 35 is added. In the state shown in the figure, after the memory means 36 finishes storing the image data of the frame of the object and records it as the next frame image data, the 5M image data of the memory means 36 is used to separate Y/C and the chroma signal is sent to the memory means 36. The luminance signal is taken into the memory means 37.

In this way, if the image data of the composite signal between frames is a still image, the image data will be exactly the same except for the hardness of the chroma signal, so that a more accurate Y/C component m can be obtained. Get more beautiful colored printout images.

In the memory control means 4, the memory means 36 and 37 store the ROMA signal and the luminance signal accurately in one frame period.

Next, an example of image enhancement by processing the luminance signal data of the memory means 37 will be explained with reference to FIG.
b may be configured in hardware, but it is a method for reading the memory means 37, and is an equivalent IH delay element having a distance between data exactly equal to the horizontal scanning period IH. 39 is a delay element corresponding to the sampling clock period mentioned above. These nine delay elements can also be obtained by accessing the memory means.

With this configuration, the c-th pixel data is multiplied by 1+h2, the surrounding vertical and horizontal pixel data are multiplied by -h, the diagonal pixel data is multiplied by -h1, and the adder 41 adds them all together. It is not returned to the memory means 37. The contours of the luminance signal processed in this way are emphasized accurately. With analog quantities, such omnidirectional differentiation is nearly impossible, and even if possible, it would be inaccurate and meaningless. This is a feature of digital processing.

However, if the hardware configuration shown in FIG. 5 is used, real-time processing is possible and the image on the monitor 7 does not look unnatural. However, it has the disadvantage that the hardware configuration is complicated and expensive. Therefore, there may be some unnaturalness on the monitor, or there is a program method that takes time but can be calculated to save hardware.

In this way, the memory means 37 stores the emphasized luminance signal. Next, the process of color demodulating the n-open signal Y and chroma signal C accumulated in the processes shown in FIGS. 4 and 5 will be explained with reference to FIG. This time, the memory means 36 does not pass through the Y/C separation means 28.
The data stored in and 37 is directly applied to the color demodulation calculation means 33. In this way, the color demodulation calculation means 33 emits emphasized R, G, and H signals. 38 and 39 in Figure 6
is an output terminal that emits a luminance signal Y and a chroma signal C, which are different from the output terminal 6 that outputs a composite signal, and also provides beautiful image data to the monitor 7.

Finally, still another embodiment of the present invention will be described with reference to FIG.

Recently, video equipment uses high resolution Y/C signals instead of composite signals.
Products that output separated analog video signals are now on the market. Therefore, the present invention attempts to deal with this as well.

FIG. 7 shows this. Input fly: children 42 and 4
3 is different from the input terminal 1 shown in FIG. 1, and has separate input terminals for the n-open signal Y and the chroma signal C. These luminance signal Y and chroma signal C are converted into digital quantities by A/D converters 41 and 40 and stored in memory means 37 and 36. Thereafter, for example, as shown in FIG. 5, the luminance signal Y is emphasized and guided to the color demodulation calculating means 33, whereby an emphasized demodulated signal of R, 01B is obtained.

〔Effect of the invention〕

As described above, according to the present invention, a memory means with a capacity of 1 frame or 2 frames is provided, and complete Y/C separation can be performed by utilizing the large correlation of pixel data between fields or frames. And, except for the A/D converter, it has aged and
Since there is no temperature change and predetermined processing can be performed on Y/C separated signals, beautiful printed images can be constantly obtained, which is very effective in practical applications.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a concrete block diagram of an embodiment of a printing apparatus according to the present invention. FIG. 2 is a diagram showing an example of the configuration of a bandpass filter used in the present invention. Figure 3 shows the frequency characteristics and Y/C of the bandpass filter in Figure 2.
FIG. 6 is a diagram showing an example of comb-shaped frequency characteristics to be separated. FIG. 4 is a diagram showing a part of a block diagram showing another embodiment of the present invention in which the memory capacity is one for two frames. FIG. 5 is a block diagram showing an example of a method for enhancing an image according to the present invention. FIG. 6 is a diagram showing an example of the color demodulation process of FIG. 4, which is another embodiment of the present invention. FIG. 7 is a partial block diagram of still another embodiment of the present invention when the input video signal is a Y/C separated signal. FIG. 8 is a block diagram of an embodiment according to the prior art. FIG. 9 is a diagram showing scanning when the composite signal is of the NTSC system. FIG. 1O is a diagram showing a specific example of a conventional analog color demodulation circuit. Applicant Seiko Epson Co., Ltd. Agent Patent Attorney Kizobe Suzuki and 1 other person Figure 3 Figure 4 Figure 5 Figure 6 Cause Figure 9

Claims (2)

[Claims] (1) In a printing device that converts a video signal, which is a composite signal, into a digital quantity using an A/D converter, digitally processes it in a predetermined manner, and prints it out, a predetermined capacity that sequentially stores the digital quantity of data is used. memory means, memory control means for controlling the memory means, Y/C separation for performing Y/C separation by calculating between data in the memory means, between fields or between frames between the memory means and data being input; means, color demodulation means for performing color demodulation calculations from the separated Y and C of the Y/C separation means, printer control means for selectively supplying the color signal of this color demodulation means to the printer, and generation of various clocks necessary for the system. 1. A printing apparatus comprising: a clock generating means for controlling the system; and a system control means for controlling the system by receiving an operation command signal from the operation command means. (2) In claim 1, if the video signal is Y/C separated, means is provided for A/D converting and directly storing each separately in the memory means. Printing device.