JP2825622B2 - Video printer adapter - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a video printer adapter for performing A / D conversion of a video signal to digital video data and printing the digital video data, and more particularly, to a slice level according to the status of the video signal. The present invention relates to a video printer adapter which can be selectively printed.

(Prior Art) A conventional video printer adapter will be described with reference to the block diagram of FIG.

The input unit 1 includes a video signal Vd to be printed, a dot clock synchronization signal Ds for sampling the video signal, a horizontal synchronization signal Hs for synchronizing one scan, a vertical synchronization signal Vs for synchronizing one screen, and printing start. Print start signal Ps
The video signal Vd is output to the A / D converter 2, and the dot clock synchronizing signal Ds and the horizontal synchronizing signal are output to the timing generator 7.
Hs, vertical synchronization signal Vs, and print start signal Ps are output.

The A / D converter 2 is set to an intermediate level between the maximum value and the minimum value of the video signal Vd so that the video signal Vd can be printed in monochrome when the first timing signal T1 output from the timing generation circuit 7 is input. Based on the slice level, a signal level higher than the slice level is determined as a black level, and a signal level lower than the slice level is determined as a white level, and is converted into binary digital video data Dd of black and white.

The digital video data Dd is input to the video signal processing unit 3, and the video signal processing unit 3 converts the digital video data for one screen into a video signal by the input of the second timing signal T2 output from the timing generation circuit 7. It is stored in the memory in the unit 3.

By inputting the third timing signal T3 output from the timing generation circuit unit 7 to the printer control unit 4, the video data Dd1 for one screen stored in the video signal processing unit 3 is read out, and the print data Dd2 is sent to the printer unit 5. Output as
The printer unit 5 performs printing based on the print data Dd2.

The timing generation circuit 7 has a dot clock synchronization signal.
Ds, horizontal synchronization signal Hs, vertical synchronization signal Vs, print start signal Ps
And a video signal selection signal Cs1 is input, a first timing signal T1 for starting the conversion of the video signal Vd into digital video data Dd is output to the A / D converter 2, and the digital video data Dd for one screen is stored. A second timing signal T2 for starting is output to the video signal processing unit 3, and video data for one screen is read out from Dd1, and a third timing signal T3 for starting to be read out.
Is output to the printer control unit 4.

The first timing signal T1 is an arbitrarily selected conversion start so that a suitable A / D conversion can be performed in response to a video signal Vd of a different scanning frequency by an external video signal selection signal Cs1. End time.

In a conventional video printer adapter, the video signal Vd input by the A / D converter 2 is converted into digital video data Dd.
In the conversion into the video signal Vd, the slice level is fixed at an intermediate level of the video signal Vd (an intermediate level between the maximum value and the minimum value of the video signal Vd).

(Problems to be Solved by the Invention) In the above-mentioned conventional video printer adapter, the video signal level of the halftone screen as shown in FIG. As shown in FIGS. 7A and 7B, when the intermediate level is printed as a slice level for different video signals A and B, the video signal A in which the halftone video signal level is higher than the intermediate level becomes black level, The low video signal B is printed at the white level. Further, even if the halftone video signal level is the same as the video signal A, the fourth
When a halftone exists in the reverse screen as in the video signal C shown in FIG. 9C, the black level portion and the halftone portion are printed at the black level.

When printing a video signal having a different halftone signal level or a video signal in which a halftone exists in the reverse screen as described above, since the slice level is fixed at the intermediate level, the level of various types of video signals is Therefore, there is a problem in that printing cannot be performed in accordance with the degree of the above, and suitable printing cannot be performed for various types of video signals.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a video printer adapter capable of suitably printing various types of video signals.

(Means for Solving the Problems) The present invention for solving the above-mentioned problems of the prior art includes an A / D conversion unit for converting a video signal into binary digital video data according to a slice level; A video signal processing unit for storing the image data for one screen, a printer control unit for reading out the video data for one screen stored in the video signal processing unit and outputting it to the printer unit, and receiving an output from the printer control unit. In the video printer adapter having a printer unit for performing printing, a signal relating to the type of video signal set in advance is input,
A level selector that determines the type of the video signal based on the input signal, selects and outputs a slice level selection signal corresponding to the type of the video signal, and D / A converts the slice level selection signal into a slice level signal. A D / A converter for performing conversion and outputting the converted data to the A / D converter.

(Operation) According to the present invention, the slice level selection signal selected by the level selection unit so that the slice level for determining the video signal to be a black and white level corresponds to the level of the video signal is added to the slice level signal. / A Convert and make variable,
Since printing is performed by converting into digital video data according to the slice level selected by the slice level signal, even various types of video signals having different levels can be suitably printed.

(Example) An example of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration block diagram of a video printer adapter according to one embodiment of the present invention.

The video printer adapter of the present embodiment has a video signal Vd,
An input unit 1 to which a dot clock synchronization signal Ds, a horizontal synchronization signal Hs, a vertical synchronization signal Vs, and a print start signal Ps are input;
An A / D conversion unit 2 that determines the video signal Vd from the input unit 1 in black and white based on the slice level and performs digital video data conversion to form digital video data Dd, and a digital video from the A / D conversion unit 2 A video signal processing unit 3 for storing data Dd as digital video data for one screen, and a printer control unit 3 for reading video data Dd1 for one screen from the video signal processing unit 3 and outputting it as print data Dd2.
And a printer unit 5 for printing based on the print data Dd2 from the printer control unit 4. Further, a dot clock synchronization signal Ds, a horizontal synchronization signal Hs, a vertical synchronization signal Vs from the input unit 1 and a printing start A signal Ps is received, a video signal selection signal Cs1 from a video switch (not shown) is received, and the A / D conversion unit 2, the video signal processing unit 3, and the printer control unit 4 start each processing. A timing generation circuit 7 for providing timing signals (first to third timing signals T1 to T3), and a level selection for receiving a signal related to the type of the video signal Vd from the video switch and outputting a slice level selection signal Cs2 according to the signal And a D / A conversion unit 6 that converts the slice level selection signal Cs2 from the level selection unit 8 into an analog signal and outputs the slice level signal Ss to the D / A conversion unit 2. You.

Then, the level selection section 8 selects the slice level selection signal Cs2 according to the signal related to the type of the video signal Vd from the video switch so that the slice level can be set in advance in accordance with the level of the video signal so that good printing can be performed. Then, the D / A converter 6 D / A converts the slice level selection signal Cs2 into a slice level signal Ss, and performs A / D conversion on the slice level signal Ss.
The slice level of the conversion unit 2 is made variable.

Next, the operation of the video printer adapter according to the present embodiment will be described.

In such a configuration, a video signal Vd, a dot clock synchronization signal Ds, a horizontal synchronization signal Hs, a horizontal synchronization signal
Vs is input and video signal selection signal from video switch
When the print start signal Ps is input to the input unit 1 while Cs1 is input to the timing generation circuit unit 7 and the slice level selection signal Cs2 from the level selection unit 8 is input to the D / A conversion unit 6, The video signal Vd is input from the input unit 1 to the A / D conversion unit 2
The dot clock synchronization signal Ds, the horizontal synchronization signal Hs, the horizontal synchronization signal Vs, and the print start signal Ps
Output to

The slice level selection signal CSs2 is the input video signal
Vd is predetermined in accordance with the type of Vd, and the correspondence is stored in the level selection unit 8. When the video signal Vd is input from the video switch to the input unit 1, the signal from the video switch is simultaneously output. The type of the video signal Vd is determined by the level selection unit 8 and automatically given to the D / A conversion unit 6.

The timing generator 7 outputs the first timing signal T1 selected by the video signal selection signal Cs1 to the A / D converter 2. The D / A converter 6 converts the slice level selection signal Cs2 selected by the level selector 8 into the slice level signal Ss
And output to the A / D converter 2.

At this time, the slice level signal Ss is
As shown in FIG. 3B, a method of converting a video signal into digital video data based on a slice level according to the present embodiment, as shown in FIG.
In the video signal A shown in FIG. 7A, the third level lower than the intermediate level is set so that the slice level becomes slice level 1.
In the video signal C shown in FIG. 3C, the slice level is set to the slice level 3 so that the halftone exists in the reverse picture so that the slice level becomes the slice level 2 in the video signal B shown in FIG. The D / A converter 6 converts the slice level selection signal Cs2 selected by the level selector 8 so as to output the signal.

The A / D converter 2 converts the video signal Vd into a digital video data Dd having a higher level than the slice level signal Ss as a black level and a lower level as a white level and a black and white binary image data Dd. The digital video data Dd is stored for one screen by the second timing signal T2 input to the video signal processing unit 3 and output from the timing generation circuit unit 7. The stored video data Dd1 is a third timing signal output from the timing generation circuit unit 7.
The data is read out to the printer control unit 4 by T3 and
Is output as print data Dd2 and is printed on printer paper.

According to the present embodiment, the slice level for converting the video signal Vd into the digital video dart Dd is determined based on the slice level selection signal Cs2 which is selected in advance to an appropriate value corresponding to the level of the video signal Vd. Since the image signal is converted into Ss and set, it is possible to suitably print even video signals of different types.

In addition, the level selection unit 8 determines and stores the correspondence between the type of the video signal and the slice level selection signal Cs2 in advance, and determines the type of the video signal based on the signal related to the type of the input video signal and slices it. Since the slice level selection signal Cs2 for level selection is appropriately selected and output, the slice level adjustment does not require any manual adjustment work, and the slice level adjustment corresponding to the type of the video signal can be performed quickly and easily. effective.

(Effects of the Invention) According to the present invention, a slice level selection signal selected by a level selection unit so that a slice level for determining a video signal to be a black and white level corresponds to a level of the video signal is a slice level signal. D / A conversion to make it variable,
Since the digital video data is converted into digital video data according to the slice level set by the slice level signal and printing is performed, even various types of video signals having different levels can be printed appropriately. There is an effect that level adjustment can be performed quickly and easily.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a video printer adapter according to an embodiment of the present invention, FIG. 2 is a block diagram showing a configuration of a conventional video printer adapter, and FIGS. 3 (a) to 3 (c) are images of the present embodiment. FIGS. 4 (a) to 4 (c) are diagrams for explaining a conventional method for converting a video signal into digital video data according to a slice level of a signal. DESCRIPTION OF SYMBOLS 1 ... Input part 2 ... A / D conversion part 3 ... Video signal processing part 4 ... Printer control part 5 ... Printer part 6 ... D / A conversion part 7 ... Timing generation circuit part 8 ... Level Selection section Vd: Video signal Ds: Dot clock synchronization signal Hs: Horizontal synchronization signal Vs: Vertical synchronization signal Ps: Printing start signal Cs1: Video signal selection signal Cs2: Slice level selection signal Ss: Slice Level signal

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-46573 (JP, A) JP-A-1-186608 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04N 1/40 H04N 5/91 H03K 5/08

Claims (1)

(57) [Claims] An A / D converter for converting a video signal into binary digital video data based on a slice level; a video signal processor for storing the digital video data as one screen; and a video signal processor. In a video printer adapter having a printer control unit that reads out video data for one screen and outputs it to a printer unit, and a printer unit that receives output from the printer control unit and performs printing, a preset video signal type Signal is input, the type of the video signal is determined based on the input signal,
A level selection unit that selects and outputs a slice level selection signal corresponding to the type of the video signal, and performs D / A conversion on the slice level selection signal into a slice level signal to perform the A / D conversion.
A video printer adapter, comprising: a D / A converter for outputting to a converter.