JPS6340492A - Color picture processor - Google Patents

Abstract

PURPOSE:To execute optimum gradation conversion by providing the first detecting means for detecting whether an input picture signal is a negative signal or a positive signal and the second detecting means for detecting the high light point and the dark point of three primary colors. CONSTITUTION:A video signal VS including respective chrominance signals of RGB and a synchronizing signal is sampled by a sample signal obtained from the synchronizing signal for every chrominance signal in a sample hold circuit 81 and outputted to an A/D converter 82. The A/D converter 82 converts the respective chrominance signals of R, G, B into a digital signal indicating a gradation and the obtained signal stores the prescribed number of lines. The data of a line memory 83 is converted into the digital signal for driving respective ink jet heads by a picture processing circuit 84. The digital signal is converted into an analog signal in a D/A converter 86 to drive the respective ink jet heads 92 through a driver 89.

Description

DETAILED DESCRIPTION OF THE INVENTION Field: The present invention relates to a color image processing device "t", and particularly relates to a color image processing device that performs gradation conversion.

<Prior Art> Conventionally, it has not been possible to manually capture signals captured by a video camera on 35 mm negative film or the like using a video printer that does not have a normal N/P inversion function. Or just RGB
Since all primary colors are inverted, 35
No correction was made for the orange base characteristic of Neka film or other coloring characteristics of Neka film, and the colors of the inverted and output image were poor.

Purpose of the Invention The present invention provides a color image processing device that can produce good results from input images ranging from normal positive images to negative images such as those captured on 35 mm negative film with a video camera.

<Embodiment> FIG. 1 shows a control block diagram of an inkjet recording apparatus for realizing the wood layer side. A video signal vS containing RGB color signals and a synchronization signal is sent to the Zambreholt circuit 81.
Each color signal is sampled using a sample signal obtained from the synchronization signal and output to the A/D converter 82. A/
The D converter 82 converts the R, G, and B color signals into digital signals indicating gradation, and stores the obtained signals for a predetermined number of lines.

The data in the line memory 83 is converted into a digital signal for driving each inkjet head by an image processing circuit 84, which will be described in detail later.

The digital signal is converted into an analog body temperature by a D/A converter 86, and drives each of the infusieras 1 to 92 via a dryer 89.

FIG. 2 shows blocks of printer signal processing on the wood flow side.

The input RGB signal is sent to A/D converter +00R.

A/D conversion is performed at 1000.100B. The R2O and B signals are the N/P inversion discrimination signal N/P and the controller I/roller 11.
Based on the gradation conversion characteristics determined according to the numerical values for each color sent from 0,
The gradation is converted by .

The converted C, M, and Y are masked by the masking section 130, and converted into 0D- by the conversion section 140.
The voltage is converted to V and converted into a corresponding head drive voltage.

(When the N/P inversion switch is on the P side) The controller controls the A/D at appropriate intervals across one image.
Take in the conversion output and find the maximum and minimum values for each color.

In the first half of each gradation level 1^ROM+20, 10h of 64 types of gradation conversion curves are stored in advance.

The data must be output with 8 pits I for each human power, that is, f ij = 255 God + 10 H juice ÷ field → system 10 Sj (human power <
Il! 10 Man power〉1 (l=25
5 Manpower<5j (i j =1.
2,---7. 8) Hi is, for example, Hi = 2
55-10*iSj is determined, for example, as 5j=10*j.

At this time, the maximum value Gmax and minimum value G that reach the green
Assuming that Hi and sj closest to 'min are Hk and Sl, the controller 110 selects the gradation conversion curve fkJ2.

This allows each RGB color to be uniformly displayed as shown in Figure 3.
Gradation conversion is performed.

In the following explanation, the maximum and minimum values Gmax and Gm1n of green were used to obtain sl and Hk, or the average value of the maximum value of each color may be used, or 0.59
A weighted average of Gmax +0.30Rmax +0.11Bmax may be used.

(When the N/P reversal switch is on the N side) In the case of manual processing such as 35 mm negative film, the orange color information is manually processed as extra color information.

This correction uses the maximum and minimum values of RGB, and N
/P Inversion is performed as follows and complementary color conversion is performed.J: Yes.

For example, ” ” ” 25×(Rmax ”−”Rm+nγ8
”” ”’ 225×(gmax ”−”Gmjn ”
0Dy"'225×(Bmax"-"Bmin rQ
It is.

γ7. γ6. The value of γ8 is fixed, for example γR=1.
γ. =1. γ, = 1.2 and γ8 is γ7°γ. It is better to set it slightly larger.

The actual operation is as follows.

The controller takes in the A/D conversion output at appropriate intervals over one image, and calculates the maximum value and value for each color.
Find the minimum value.

In the latter half of the gradation conversion ROM, 64 types of gradation conversion tables are written in advance. Both data output and input are 8
As bits, i.e. Gij=255x(FHHday−γ8 Sj<input<1(i=0 human power>Hi=255
Human power < Si (i = 0.1---
−−7, j =0.1−−−−−7) Hl is H
4=255-10*i Sj is 5j=10*j At this point, for example, R is the maximum value Rmax and minimum value Rm of R
Assuming that H4 and sj or l■kR, Suk are closest to in, the controller uses Gl as the conversion characteristic for R.
Select j.

The same applies to the other G and B. This situation is shown in Figure 4.

In another embodiment of FIG. 2, the A/D converter may be integrated into one (or may be used in a time-divided manner).

Effects> With this configuration, optimal gradation conversion can be performed depending on the negative, positive, highlight points, and dark points of the input image signal.

[Brief explanation of the drawing]

FIG. 1 is a control block diagram of the inkjet recording apparatus shown in FIG. 711, FIG. 2 is a detailed circuit diagram of the image processing circuit 84 shown in FIG. It is.

Claims (1)

[Claims] 1) A first detection means for detecting whether the input image signal is a negative signal or a positive signal, a second detection means for detecting the highlight point and dark point of each of the three primary colors R, G, and B, and the output of both detection means. , a color image processing device that selects one of gradation conversion patterns written in advance in a memory.