JPS6014571A - Gradation setting device in picture input and output system - Google Patents

Abstract

PURPOSE:To increase the accuracy of gradation processing and to improve the working efficiency by forming an xy coordinate system where an input picture density signal is taken as the x axis and an output picture density signal is taken as the y axis so as to form an intermediate coordinate point for several parameters and forming a gradation curve through the interplation such as quasi-Hermite interpolating method among coordinate points. CONSTITUTION:The x, y axes and y=lx are generated by a normal straight line generating means 1, the x axis is rotated counter clockwise around the origin of the xy coordinate by the 1st coordinate rotating means 2, the x axis is converted into the alpha axis and the y axis is converted into the beta axis so as to form the alphabeta coordinate axes. Then each coordinate point is generated on the alphabeta coordinate system according to each parameter inputted by a coordinate point generating means 3. Thus, the alphabeta coordinate axes are rotated by the 2nd coordinate rotating means 4, the alpha axis is converted into the x axis and the beta axis is converted into the y axis so as to form the xy coordinate system. Further, the coordinate points on the xy coordinate system are interpolated by the quasi-Hermite interpolating method by using a gradation curve generating means 5 so as to form the gradation curve.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a gradation setting device that performs gradation conversion from a human-powered image coefficient to an output image signal in a high-precision image input/output system such as a high-precision inkjet printer (for example, Autokon manufactured by ECILM), More specifically, the present invention relates to a gradation setting device that generates a gradation conversion curve used when performing this gradation conversion.

For example, in a color scanner or the like, an input image optical signal incident on an input head is photoelectrically converted by a photomultiplier tube.
If necessary, the signal is logarithmically converted in a logarithmic conversion circuit, then input to a signal processing device centered on a gradation setting device and converted into a desired output image signal, and then converted into an output image light amount signal in a light amount control circuit. After that, the output head exposes the photosensitive material as an output image. The tone conversion from the input density signal to the output density signal performed by the tone setting device is as follows:
In general, this is performed based on a gradation conversion curve that is generated using each setting value set by the highlight, mitre, and shadow potentiometers on the operation panel as parameters. Hereinafter, the conventional process of generating this curve performed in a gradation setting device will be specifically described.

These parameters (H, h4, S) are h(x), +n(x) generated by the gradation setting device, respectively.
, s(x). Examples of these basic functions are shown in Figures 1A and 13, respectively.
Illustrated in FIG. 1C. (However, the horizontal axis (x11411)
represents the input concentration signal, and the vertical axis (y-axis) represents the output↓limb multiplied signal. The same applies to Figure 11) and Figure 1E below. Also,
The scale values of the X-axis and the y-axis are common in FIGS. 1A to 1E. ) Note that the amplitude of these basic functions changes according to the set value (parameter) of the potentiometer. In other words, each setting value (parameter) means a weight that can be applied to each basic interval ζ.

Next, a direct link relation y = IJ x (l is a constant) passing through the origin is generated, and the basic functions h(x), m(x
).

5(x), the corresponding parameters I-1゜hi, s are integrated, and then the function p (1-I X 11(x) + M X m(x)
S×5(X) ) is generated, and then the two generated functions are superimposed on each other to generate the tone curve function y.

The Zunawara gradation curve function y is expressed by the following equation.

y = l-I X b(x)-1-M, xm(x)-l
-8x 5(x)-tlx...1) (However, 11
However, depending on the gradation curve function generated by such a gradation setting device, several problems may occur as shown below.

The first problem is that operators typically highlight,
The gradation changes in the middle and yado areas are y =
Even though it is desired that the change be made in a direction perpendicular to the straight line of ll x , it does not actually change in that way, so it may be difficult to handle it operationally. In other words, For example, when I-T-8-〇~1 to 11 and -11111 (however, lX11>O)
If given, the two functions M+
, ``Ruka, two-order R14 curve function 1\j, + x m
(x) + lJx and -I\4+ xm(x) +
lx fiy = intersects with the straight line QjA of lX, and there is no line-symmetrical relationship.

As a second problem, the distance between the base fabrics Q l+(x) , l1l
(X).

Since the form of S (X) is determined, the parameter I
Depending on the gradation curve function generated by the combination of only I, M, and S, it may be difficult for the operator to create the desired 1-to-all song i;

A third problem is that depending on the combination of parameters II, M, and S, this gradation curve does not become a monotonal increasing curve. That is, inversion of gradation may occur.

The present invention has been made to solve the above problems, and by generating a gradation curve that does not cause the above-mentioned problems, and furthermore, by using this curve, it is possible to generate the output image signal desired by the operator. The purpose of this invention is to provide a gradation setting device capable of outputting .

The gradation setting device in the image density control system according to the first aspect of the present invention is a gradation setting device that outputs an image density signal subjected to gradation processing using a gradation curve. An output image 11 j is formed with the position signal as the y axis, and an xy coordinate system is formed by taking the immersion level signal, and a reference straight line 5 of y-lx (l is a constant) is generated on this xy coordinate system. In addition, the x and y coordinate axes are rotated counterclockwise around the origin so that the te, α
A first coordinate axis rotation means forming a β coordinate system is provided, and a minimum value coordinate point Pm1n and a maximum value coordinate point P m a x are generated on the α axis of this αβ coordinate system, and the minimum value coordinate point Pm1n and α between the maximum value coordinate point PmaxO
Several parameter river intermediate coordinate points with different values are generated, and the β values of these intermediate coordinate points can be changed arbitrarily, that is, the minimum value coordinate point Pm1n, the maximum value 1i? A coordinate point generation means capable of generating j I'l-gage point Pmax and several intermediate points that can be varied in the β-axis direction is provided, and this αβ coordinate=
Rotate only i in the tense direction around the origin until αl1ill overlaps the X-axis formed by the standard straight line generating means, and set the α-axis to the X-axis and the β-axis to the
A second seat and a floating rotation means are provided for converting the 1-point standard thread into a 1-point standard, and further, the coordinate points in the converted The present invention is characterized in that it is provided with a gradation plane side generating means for generating the sand.

Next, the gradation setting device in the image input/output system of the second aspect of the present invention is a gradation setting device that outputs an image iM degree signal subjected to gradation processing using a gradation curve edge.
X1II141 and the input image preparation signal, ylilI
As II, an xy coordinate system is formed by taking the output image density signal, and a reference straight line generating means for generating a reference straight line of y=lx (l is a constant) is provided on this xy coordinate system, and this xy coordinate axis is , centered on the origin and 1. and rotate in the counterclockwise direction to set x i+++ to 1 on the reference curve, and at this time
αβ with iil+ as αtiIIIl and y axis as β axis.
A tenth mark axis rotation means forming a coordinate system is provided, and
A minimum value coordinate point Pm1n and a maximum one rectangular coordinate point Pmax are generated on the α axis of this αβF3 system, and intermediate points for several parameters having different α values are generated between the minimum value coordinate point Pm1n and the maximum value coordinate point PmaxO. Coordinate points are generated, and β11A of these interaural coordinate points can be changed arbitrarily, that is, a minimum value coordinate point Pm1n, a maximum value coordinate point Pmax, and several points that can be changed in the β axis direction. A coordinate point generating means is provided which can generate an intermediate coordinate point of the gradation curve by interpolating between the respective coordinate points in the αβ locus 1i, :li system by the quasi-Hermite tili interval method or the like. A gradation curve generating means for generating a gradation curve, and only this αβ coordinate axis are rotated in the horizontal direction about the origin until the α axis overlaps with the X axis formed in the standard straight line generating means, and the α axis is set as the X axis, The special purpose is to provide a second coordinate axis rotation means that forms an xy axis system with β1iib as the y axis.

2T to 2T are graphs showing examples of xq*, y axes and y = IJ An example of the slag system is given in AfJ Book X 1i41]
The graph shown with the and ) and axes, Figure 2C, shows the minimum value coordinate point Proin, the minimum value coordinate point Pmax, and several intermediate coordinates generated by the coordinate point generation means on the αβ coordinate system. Figure 21 is a graph showing an example of a point along with the xikll and y axes, and Figure 21 is a graph showing that each coordinate point has been transformed into an xy coordinate system by the second coordinate axis rotation means. , x by the gradation curve generating means
It is a graph showing an example of a gradation curve generated on the ym standard system.

Note that the α coordinates of the maximum value coordinate point and the minimum value coordinate point are values corresponding to the maximum value and minimum value of the signal in the human image.

In addition, the number of intermediate coordinate points may be set to a desired number of 2 or more;
The stability for curve generation may be improved by providing coordinate points that are less than or equal to n or greater than or equal to the maximum value coordinate point Pmax.

Further, as a method for interpolating each of the coordinate points IHj, an interpolation method using a spline, for example, in addition to the above-mentioned quasi-Hermite interpolation method may be used.

According to the gradation setting device in the image input/output system of the present invention, it is possible to select a desired number of coordinate points to be parameters used when determining a gradation curve, and αlff1 standard of each coordinate point can be selected. You can set each to the desired value, so you have a high degree of freedom in generating gradation curves.
Can generate smooth curves.

Therefore, highly effective gradation processing can be performed.

Furthermore, since the device of the present invention is equipped with a seat (biaxial rotation means), it is possible to change the valley midway reference point by moving 7'' to the jJt semi-straight line of y = (lx). The gradation curve also follows the parameter value set by the operator, y=4
It changes with respect to the standard spot object of x. As a result, the operator can input the 1st key piece Ifbl that changes with respect to the straight line of h[desired y=lx. For this reason, embodiments of the present invention that can improve work efficiency will be described in detail below.

FIG. 3 is a block diagram showing one embodiment of the apparatus according to the first aspect of the present invention.

X'IQII + >Qlh by the standard straight line generation means 1
, and y=ll
It is rotated counter-chronologically until it is east of the straight line of l x, and this rotated
It is converted into li+ to form an αβ coordinate axis. After this,
The coordinate point generating means 3 generates each coordinate point on the αβ standard reference system according to each parameter value input. Thereafter, the second coordinate axis rotation means 4 rotates only this αβ coordinate axis in the same chronological direction with the origin as the center, and the reference straight line generation means 1 forms 9X'! 'l: It is rotated until the α axis overlaps with l, and the α axis is converted to X 1llllll and the β axis to Y Qi+ to generate an xy coordinate system. After this, gradation 1
The fit generation means 5 interpolates between each coordinate point on the xy reference system using the quasi-Hermitian abstraction method to obtain a floor; il, J [11]
Ivj! is generated. Based on the gradation curve generated in this way, input 1. is input to the gradation setting device.
I! ! 1fJ'; The dark 1 signal is converted into an output image (-summer IK number. The tl-4 diagram shows the y-axis and y-axis formed by the standard straight line generation means 1, and the first coordinate axis rotation means 2, The xy axis is rotated around the origin by degrees θ in four counterclockwise directions, resulting in tbJ and α elevation j(y − (
! x's J, l'l, lewd + shi 夛 and 箪Naru) and β1
11111, 1 is a graph showing eight coordinate points 1'+ -Ps (P2 and P7 are fixed points) generated on α1Ilil by the raw middle point cow generation means 3.

As a specific method for generating sitting body points, first, the operator sets the highlight, middle, and shadow parameter values 11. M, S are set and these 11, 1\I, JHqH are input to the coordinate point generation means 3, and each of P1 to P8)
The β14S mark of the zadriku point is determined. For example, P+ is one piece, P2 is 0, Ps is H
-, P4 and Ps are l\1, P6 is S, P7&-
1:01P8 will have one β coordinate.

Next, these hardness (α month j of vertices P1 to P8 (out of votes, P2 (minimum value 1 vote point) is 0, P7 (maximum value coordinate point)
is set to a normalized value of 1,00.

Note that αj sitting full image O and 100 are input images 1. ′↓
Corresponds to the minimum density value of the signal and the maximum 0 degrees and 1 shift. Generally, the ranges of the highlight, middle, and shadow areas are 5 to 35 degrees for highlights, 30 to 7 degrees for middle, and 65 to 95 degrees for shadows. In this embodiment, the za 1 vote point P3 corresponding to the highlight is 15, and the j za 1 vertex P4 .corresponding to the middle is 15. 1. +5 (two points are taken to generate a smooth gradation curve) is 49.
51, the coordinate point P6 corresponding to the shadow is α1 of 85! I
≦ mark.

In addition, the coordinate points P1 and 1ゝ8 are each 1 mound.
1 ' S (15,) , (] l 5.2 ). These two points (1 so; point (, 11, floor fi+-, i 1+
When generating record 11? ζ Qualitative (1), (in Japanese)

Next, 2nd seat 4 votes 'I% 1 time 1 time, hand 1 goku 4 α
βj landmark system − ni no j” landmark J,’+ ~L’s xy
m standard thread 10) pJ45A Vc conversion. The coordinates (α, β) of one vote point for each locus are the following 2
) coordinate (x).

y) converted into two (Note that θ is the angle formed by the y-axis and α1qi+.

) Next, the tone generation means 5 calculates coordinate points P1 to P80 of the xy coordinate system obtained as described above (X+
+Y+) (""L ..., 8) using the quasi-Hermitian complement 1i-IJ method (for example, Fujitsu Ltd. 1!"ACO1~41i'OE'l"1LAN 5
SLlr Tsugetsu” Tehikii c+9sp-0050-4P23
5 to 237)), the coefficient sequence cidl
+ e, (””■+ ”'+ 7) is observed.

After this, a rank i1.,1 curve is generated by these coefficient sequences c+ + "I l el,"!
In the interval of X 1 <
X)X=y, 10cIIlx+(1; *x2+e
1・x3−・−・・・・3)
- Force generation SW 9, a'r 5 N &j: is a graph showing an example of the gradation fl111:Jl generated in this way. This figure shows 17 gradation divisions generated for each parameter by varying the parameters. From this figure, we can see that the gradation curve as the parameters change is y =
(It can be seen that the reference line of t In this example, the parameter 1-■ can be obtained.

1'vi, 517J and cl, d;
Since it is possible to determine the parameters e and , it is possible to freely generate a large, smooth curve in curve generation. In addition, although we selected 15°49.51.85 as the α coordinates of no illite, middle, and shadow, these industrial wastes can be changed to any value, and this change increases the degree of freedom when generating curves. It gets even bigger. Further, according to this embodiment, when a combination of CI + dl leI that does not result in a monotonically increasing gradation curve is input, it is possible to set in advance so that the combination can be blocked. Therefore, it is easy to generate only a monotonically increasing curve.

The block diagram of the embodiment according to the second invention of the present invention is the second coordinate of the block diagram of FIG.
1111 The rotating means 4 and 1: can be rotated by 1d by replacing the generating means 5. This embodiment also provides the same effect as the above embodiment.

In the above two embodiments, each means is a microprocessor (for example, Z-80), It(JIvl,
It may be formed by using a digital circuit that combines 14 AM, etc., or it may be formed by using an analog circuit that combines multiple non-linear amplifiers.

[Brief explanation of drawings]

1A to 1E are graphs explaining the prior art, and FIGS. 2A to 2D are graphs showing coordinate axes, rotation points, and 1st gradation curves generated by each + stage of the apparatus of the present invention. , Fig. 3 is a block diagram showing an example of the implementation of Fig. 3, Fig. 4 is a graph showing the method of generating vertices in the implementation 17 of Fig. 3, and Fig. 5 is an implementation of Fig. 3. It is a graph showing a gradation curve generated according to an example. 1... Rule [-@總Generation means 2... First coordinate axis rotation means 3... Coordinate point generation means 4... Second coordinate axis rotation means 5... Gradation curve generation means Figure 1A Figure 0 (2) Old figure Figure 2B Figure 2C Figure 1 [Figure 2D

Claims (2)

[Claims] (1) In a gradation setting device that performs gradation processing based on a gradation curve on a human-powered image density signal from an image signal human-powered device, and sends the output image density signal after this gradation processing to an image signal output device. , an xy coordinate system is formed in which the input image m11 signal is taken as the X axis and the output image signal is taken as the y axis, and further this xy
A reference straight line generating means for generating a reference straight line of y-lX (where l is a constant) on a coordinate system; rotating this xy coordinate axis counterclockwise around the origin until the X axis overlaps the reference curve; After rotation, the first axis forms an αβ coordinate system with the X axis as the α axis and the y axis as the β axis.
The coordinate axis rotating means generates a minimum value coordinate point P1 old 1] and a maximum value 1φ1 (reference point pH12X) on the α axis of this αβ coordinate system, and also generates the minimum value coordinate point P1 old Intermediate II a'' for parameters with 4161 different α values between points PmaxO; points are generated and the β values of these intermediate points can be changed at will +3Ji
Only the αβ coordinate axis with the fJ point generation means is rotated in the 11 direction around the origin until the α axis overlaps the X axis formed in the reference straight line generation means, and the α axis is the α axis, the second to form the Xy standard system.
J complete image axis rotation means, and interpolates between each of the coordinate points in this transformed xy coordinate system to obtain the above-mentioned coordinates! 4?A gradation curve generation means is provided to generate A gradation setting device for the image quality and tone used as a sign. (2) Perform gradation processing based on the gradation curve on the input image signal from the image signal input device, and output the output after this gradation processing to the image signal output device. In the floor/tsutomu setting device that sends out the image, a full image of the xyl sitting position is formed, with the input image 9 degrees No. 18 as the X axis and the output image density signal as the y axis.
A reference straight line generation means for generating a reference straight line of y-lX (where l is a constant) on the y-coordinate system, and the origin of this xy coordinate axis is cut in the center until the X-axis overlaps with the reference curve, and the After rotation, the first coordinate axis rotation means forming a system, the minimum on αll1111 of this αβ coordinate system, Buddha seat 1:;i
A point Pm1n and a maximum value coordinate point Pmax are generated, and several intermediate coordinate points for parameters with different α values are generated between the minimum value coordinate point L'min and the maximum value coordinate point PmaxO. This α is a coordinate point generation means that can arbitrarily change the β value of a coordinate point.
gradation curve generation means for generating the gradation curve by interpolating between the coordinate points in the β coordinate system; The double edge is characterized by being provided with a second rotating means that rotates clockwise around the origin to form an xy coordinate system with the α axis as the X axis and the β axis as the y axis. Level 1 in the entry and exit Kanstem
4 setting device 1σ0