JP3197574B2 - Video Printer Image Quality Adjustment Method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for adjusting the image quality of a video printer having a monitor output function of a video signal to be printed and a function of adjusting the quality of a printed image.

[0002]

2. Description of the Related Art Conventionally, a video printer having a monitor output function and a print image quality adjusting function is disclosed in, for example, Japanese Patent Application Laid-Open No. 63-1.
As described in JP-A-79677 (H04N 5/91), the configuration is substantially as shown in FIG. Then, the analog input video signal of the input terminal 1 is supplied to the YC separation circuit 3 of the input processing circuit 2.
Separates the input video signal into a luminance signal and a carrier chrominance signal.

[0003] The luminance signal of the separation circuit 3 is A
A / D conversion circuit 4 converts the carrier chrominance signal of the separation circuit 3 into RY and BY color difference signals by a decoder 5 and supplies it to an A / D conversion circuit 4. By the conversion, luminance data of the input video signal and two kinds of color difference data are formed. Further, each data of the A / D conversion circuit 4 is supplied to a memory 6 for holding printing information in a frame memory configuration, and the digitally converted input video signal is taken into the memory 6 while being rewritten.

[0004] Each data fetched into the memory 6 is read out to a D / A conversion circuit 7 on the monitor output side and is converted into an analog signal. The luminance signal and the two color difference signals formed by the analog conversion are processed by the monitor output processing. The color signals are supplied to the YC superimposing circuit 9 and the encoder 10 of the circuit 8, respectively. The carrier chrominance signal is reconstructed by the color signal modulation processing of the encoder 10. Is done. The superimposing circuit 9 superimposes the carrier chrominance signal on the luminance signal and synthesizes the same to generate an analog monitor video signal similar to the input video signal.

[0005] The monitor video signal is supplied from an output terminal 12 to a monitor television or the like and is displayed on a monitor. Each data of the desired screen taken into the memory 6 is supplied to a microcomputer 13 for controlling the whole as printing data based on a printing command or the like, a driving circuit 14, and a printing processing circuit of a printing head 15. Then, the printing head 15 prints out the color printing image of the desired screen by, for example, sublimation type thermal transfer.

By the way, the processing circuit 8 is provided with a variable resistor 16 for an image quality adjusting volume as an image quality adjusting means.
Is applied to the saturation adjustment circuit 11 (hereinafter, referred to as an image quality adjustment voltage). As shown in FIG. 3, the saturation adjustment circuit 11 includes a voltage control amplifier (hereinafter referred to as VCA) 18, a changeover switch 19, and a variable resistor 2 for controlling the control voltage of the VCA 18.
The VCA 18 is gain-controlled by an image quality adjustment voltage via the resistor 22.

Further, the switch chrominance signal of the encoder 10 and a signal obtained by amplifying the signal by the VCA 18 are connected to the switch 1.
9, the switch 19 is switched by a burst gate pulse of a burst gate pulse generation circuit (not shown), and the output signal of the switch 19 is switched from the signal after amplification of the VCA 18 to the signal before amplification only during the burst gate period. Instead, the carrier signal is adjusted to a level corresponding to the image quality adjustment voltage by holding the burst signal at the original reference level. Based on this adjustment, the image quality (chroma) of the monitor video signal at the output terminal 12 changes according to the image quality adjustment voltage.

Conventionally, in order to adjust the image quality of a printed image using the image quality adjustment voltage, conventionally, the image quality adjustment voltage of the sliding piece of the variable resistor 16 is digitally converted and taken into the computer 13 as it is. 24, a correction coefficient k corresponding to the image quality adjustment voltage is set.
Is used to perform the image quality adjustment calculation of Equation 1, for example.

[0009]

(Equation 1)

By this image quality adjustment operation, the luminance data y ₀ and the chrominance data u _0, v ₀ read from the memory 6 are adjusted to the data y _1, u _1, v ₁ and supplied to the drive circuit 14 to be printed out. The printed image also changes according to the image quality adjustment voltage.

The image quality adjustment voltage is applied to the variable resistor 16 in a preset state in which the sliding piece is located at the center.
The reference value is set to be the reference value of cc / 2, but actually fluctuates from the reference value in the preset state due to variations in the variable resistor 16 and circuit constants. Then, when the image quality adjustment voltage in the preset state fluctuates, especially the printing image quality characteristic based on the image quality adjustment voltage fluctuates from the reference characteristic.

Therefore, conventionally, the variable resistance 20 of FIG. 2 for calibrating the image quality adjustment voltage is provided in the saturation adjustment circuit 11, and the variable resistance 16 is held at the center position at the time of manufacturing or the like, and the image quality adjustment voltage is measured. The variable resistor 20 is adjusted so that this voltage becomes the voltage of the reference value of Vcc / 2.

[0013]

In the image quality adjusting method of the conventional video printer, the variation of the image quality adjusting voltage based on the variation of the variable resistor 16 and the circuit constant is adjusted by adjusting the variable resistor 20 while measuring the image quality adjusting voltage. However, there is a problem that a complicated calibration operation is required and calibration cannot be simplified because the calibration is performed and corrected by a manual operation.

When the hue adjustment, the brightness adjustment, the contrast adjustment, and the like are performed by the image quality adjustment voltage, for example, a variable resistor similar to the variable resistors 16 and 20 is provided for each adjustment. In this case, the same problem as described above occurs. Occurs. SUMMARY OF THE INVENTION It is an object of the present invention to provide a printer image quality adjustment method in which an image quality adjustment value (image quality adjustment voltage) is calibrated by a simple method suitable for automation.

[0015]

In order to achieve the above-mentioned object, in the image quality adjusting method for a video printer according to the present invention, when calibrating the image quality adjustment, the reference value in the preset state of the image quality adjusting means and the actual adjustment are adjusted. The difference from the value is detected and held as a correction value in a memory for calibration, and the adjustment value of the image quality adjusting means is normally calibrated by the correction value in the memory for calibration.

[0016]

In the case of the adjusting method of the present invention configured as described above, a correction value corresponding to the variation of the image quality adjusting means and the circuit constant is held in the memory for calibration during calibration, and the correction value of the memory for calibration is normally used. The printing image quality is adjusted based on the adjustment value (image quality adjustment voltage) corrected by the correction value. Therefore, a complicated calibration operation for adjusting the variable resistance while measuring the conventional image quality adjustment voltage is omitted, and the adjustment work at the time of manufacturing or the like is simplified.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment will be described with reference to FIG. 1 is different from the conventional configuration of FIG. 2 in that a correction circuit 25 for image quality adjustment voltage calibration is provided and the computer 1
3, the control processing function of the calibration mode is added, the variable resistor 20 of FIG. 2 of the saturation adjustment circuit 11 is omitted, and the image quality adjustment voltage via the correction circuit 25 is supplied to the arithmetic circuit 24 and the saturation adjustment circuit 11. It is a point that was made. Note that the correction circuit 25
It has a / D conversion circuit 26, a memory 27 for holding a calibration value, a subtractor 28 for detecting a difference, a switch 29, and an adder 30 for correcting and combining.

When correcting the variation in the image quality adjustment voltage of the sliding piece of the variable resistor 16, the sliding piece of the variable resistor 16 is preset at the center position, and the image quality calibration is instructed to the computer 13 by operating a button or the like. At this time, computer 1
3 switches from the normal mode to the image quality calibration mode, and supplies the subtractor 28 with the reference value (= V) of the image quality adjustment voltage in the preset state.
cc / 2) of data.

The data of the actual image quality adjustment voltage in the preset state of the variable resistor 16 is supplied from the A / D conversion circuit 26 to the subtractor 28. Then, by the subtracter 28,
The difference between the data of the reference value and the data of the actual adjustment voltage, that is, the variation of the image quality adjustment voltage based on the variation of the variable resistor 16 and the circuit constant is detected.

Further, the switch 29 is turned on only in the image quality calibration mode by the latch signal of the computer 13, and the memory 27 is in the write state, and the data of the difference of the subtracter 28 is held in the memory 27 as the data of the correction value for calibration. Is done. When the data of the correction value is written and held in the memory 27, the computer
Returns to normal mode.

In the normal mode, the switch 27
Is held off, the memory 27 is held for reading, and the data of the correction value is supplied from the memory 27 to the adder 30. Then, the adder 30 adds the data of the correction value to the data of the image quality adjustment voltage of the sliding piece to the variable resistor 16 via the A / D conversion circuit 26, and corrects the image quality adjustment voltage by an amount corresponding to the variation, The corrected image quality adjustment voltage data is supplied to the arithmetic circuit 24 and the computer 1
3 and is supplied to the saturation adjustment circuit 11.

Therefore, by the automatic processing of the computer 13, the correction value for calibration is held in the memory 27 of the correction circuit 25, and the fluctuation based on the variation of the image quality adjustment voltage is automatically calibrated and corrected based on the correction value. This eliminates the need for conventional manual and complicated adjustment work. In the above-described embodiment, the calibration of the saturation adjustment has been described. However, the calibration of the hue adjustment, the luminance adjustment, and the control adjustment can be automated in the same manner as described above. Further, the image quality adjusting means may be other than a variable resistor.

[0023]

Since the present invention is configured as described above, the following effects can be obtained. By the calibration of the image quality adjustment, the difference between the reference value in the preset state of the image quality adjustment unit and the actual adjustment value is detected and held as a correction value in the memory 27 for calibration. Is calibrated by the correction value of the memory 27, the fluctuation of the image quality adjustment value based on the variation of the image quality adjustment means and the like can be calibrated much more easily than in the case where manual adjustment is performed while measuring the conventional adjustment value. Adjustment work at the time is simplified.

[Brief description of the drawings]

FIG. 1 is a block diagram of an embodiment of an image quality adjusting method for a video printer according to the present invention.

FIG. 2 is a block diagram of a conventional image quality adjustment method.

FIG. 3 is a detailed block diagram of a part of FIG. 2;

[Explanation of symbols]

 Reference Signs List 6 Memory for holding printing information 8 Monitor output processing circuit 15 Printing head 16 Variable resistor for image quality adjustment volume 27 Memory for calibration

Continuation of the front page (56) References JP-A-2-274067 (JP, A) JP-A-2-250465 (JP, A) JP-A-2-105686 (JP, A) , U) Shokai 61-258566 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5/76-5/937 H04N 5/14-5/217

Claims (1)

(57) [Claims] An input video signal is fetched into a memory for holding printing information, a holding signal of the memory is read, and supplied to a printing processing circuit and a monitor output processing circuit. Along with generating a printed image, the monitor output processing circuit processes the holding signal to generate a monitor video signal, and an adjustment value variably set by image quality adjustment means provided in the monitor output processing circuit,
In the image quality adjusting method of a video printer for adjusting the image quality of the printed image together with the monitor video signal, a difference between a reference value in a preset state of the image quality adjusting means and an actual adjustment value is detected by calibrating the image quality adjustment. A calibration value stored in a calibration memory as a correction value, and the adjustment value of the image quality adjustment means is calibrated by the correction value of the calibration memory in a normal state.