JPS62111569A - Automatic setting method for output signal processing condition in image input/output system - Google Patents

Abstract

PURPOSE:To attain highly accurate automatic setting of an output signal processing condition by detecting the density of a feature point on the basis of a prescribed method. CONSTITUTION:To find out the density of picture element data on the coordinates of a feature point of a color original 2, a signal processing part 5 and microprocessor 12 execute the following processing. Namely, picture elements near the feature point are divided into several areas, a picture element including noise is removed and the average density in each area is calculated on the basis of the residual picture elements. Then, the representative density as the feature density is found out on the basis of the inherent deciding condition of the feature point such as highlight or shadow. Since no noise is included in the density of the feature point, an exact calculation result can be obtained and the highly accurate setting of the output signal processing conditions can be attained.

Description

Detailed Description of the Invention (9. Technical Field of Ming) This invention relates to a method for automatically setting processing conditions for obtaining a desired finished image with high precision on a final output image in a color image input/output system. .

(Technical background of the invention and its problems) In a color image input/output system, gradation processing is generally performed on each color output density signal from an image input device (for example, a color scanner) that separates and reads a color original. , a force V is used to input each color output density signal after gradation processing to an image output device (for example, a laser color printer, a halftone scanner, etc.). A specific method in this case is to create a density histogram of pixel data for the human density signal, and specify the spot color points (for example, highlight points, Nyado points, etc.) as specifiers to determine the spot black density. There is a method in which the color image processing conditions are automatically set by calculating the density signal and automatically setting the color image processing conditions. In general, pixel data obtained from an image input device often contains a considerable amount of noise.For example, this may be caused by the graininess of the photosensitive material, noise generated by the input device itself, or dust adhesion. This is the main cause. Furthermore, the accuracy of the positional relationship of pixel data is determined by, for example, the error between the document position on the input drum and the specified input position of the digitizer, but this positional error inevitably exists physically, and this may affect the quality of the output image. This is because they are being kept.

(Purpose of the invention) This invention was made out of the above-mentioned circumstances.
An object of the present invention is to provide a method for automatically setting output signal processing conditions with high accuracy by modifying the C degree detection method of a spot feature point.

(Summary of the Invention) This invention provides a double-image input tray for color-separating and reading a color original.
Each color input density signal from the device is input to the signal processing section, and each color gradation process is applied to each of these signals.1. This paper relates to a method for automatically setting output signal processing conditions in a color image input/output system that inputs a color output density signal after color printing to an image output device. Find the density of pixel data at multiple points near the point coordinates, remove pixel data with density that includes noise from the pixel data at these multiple points σ), and then calculate the average density of the pixels at the multiple points; Calculate the value 17, calculate the representative density of the distribution color point by -1 from the average density value according to the predetermined judgment criterion, and calculate this representative density (from f = image processing conditions for the above power density signal) is set automatically.

(Embodiment of the invention): 511.2! 1 is a bronc block diagram showing an embodiment of an image input/output system that realizes the present invention, in which a color original 2 pasted on a rotating input drum 1 is digitized with a digitizer 14 as a UA human-powered device. In accordance with the manually inputted information, a portrait is output on a recording material such as a photosensitive material 11 attached to a rotating output drum t-10. The color original 2 is color-separated by a dot (not shown) before being read, and a color-separated signal C5 obtained by reading the image information is input to the logarithmic conversion circuit 3. The logarithmic conversion circuit 3 converts the signal into a concentration signal [IN, and then the A/D converter 4 converts it into a digital signal DS. This digital density signal IIS is input to the signal processing section 5 and the microprocessor 12, where it undergoes color processing such as color correction in the processing section 5 and gradation conversion processing in the sharpness enhancement section 9. This color-processed image The information DSA is converted into a network signal OT by the network conversion circuit 6.
After being converted into s, the laser beam is input to the modulator 8 in the output optical system of the laser 12, modulates the laser beam from the laser generator 7, and outputs it to the output drum 1 via an output converter (not shown).
Photosensitive material (for example, Lith film 11) pasted on the 0hi
It is designed to be exposed to light.

On the other hand, a console 16 equipped with a keyboard is provided as a data and command input device, and data etc. input from the console 16 are input manually to the computer 13.
Information processed by the computer 13 is displayed on an interactive graphic display 15. Further, the computer I3 is further connected to the microprocessor 12 of the lower system, and the computer I3 is connected to the microprocessor 12 of the lower system.
2 inputs the concentration signal OS from the A/D converter 4, and is further connected to the signal processing section 5 to perform @page processing.

The computer 13 and the microprocessor 12 constitute a computer system, and instructions to the operator etc. are displayed on the graphic display 15 according to a built-in program. Further, the positions of the input drum 1 and the output drum IO are detected by a detector (not shown), and the position information is inputted to the operation control section 9. At the same time, the operation control section 9 controls the input and output drums IO. and 10 are connected to the microprocessor 12 so as to control the relative positional relationship between the two.

Furthermore, the digitizer 14 uses the device-specific origin coordinates and
Although it has a −Y axis, the origin can be easily moved to an arbitrary point or the coordinates can be rotated by signal processing.

The image positions of the digitizer 14 and the input drum lJ: are made to correspond by providing guides such as pins at a plurality of common positions. The digitizer 14 is connected to the computer I3 so that the desired shape and position coordinates of the image can be input.

FIG. 2 is a block diagram showing a method of generating image processing condition setting parameters in the signal processing section 5. As shown in FIG. First, the input information is the prescan data and the primary ■~<q+
Two special point power barometers as shown in the figure below are used.

The items to be specified as this special feature point power parameter are:
(1) Highlight point coordinates, ■Shadow point coordinates, (Φ gray point coordinates, ■Skin color point coordinates, (Φcolor specified point coordinates)
Pre-scan data at coordinate points for these five items is calculated as spot color point density, and the result is subjected to gradation calculation and color correction calculation processing.

Further, after the prescan data is subjected to cumulative histogram calculation processing 5, it is subjected to gradation calculation processing. As described above, a gradation table is automatically set from the result of the gradation calculation process, and a color correction coefficient is automatically set from the result of the color correction calculation process, respectively, as output condition setting parameters.

Here, to explain the 5th item [1 of the spot color point power parameter, by inputting the coordinate points of these 5 items from the digitizer 14, for example... It is set as 1. Similarly, for one point of shadow, one point of nyad in the gradation table is specified. For a single gray point, the gradation table is set so that the specified point is finished in gray. As for the skin color point, a gradation table or color correction coefficient is set so that the point has an appropriate skin color. Finally, for a designated color point, a gradation table or color correction coefficient is set so that the point has a designated density or dot area ratio.

By performing @page processing in this way, the gradation table and color correction coefficient can be automatically set as the output condition 1 fixed parameters, but the pixel data used for this calculation process is as described above. It often contains quite a bit of noise. Therefore, in this method, first, not only the data for the image corresponding to the spot color point coordinates, but also the data of multiple pixels in the vicinity of that pixel data as medium/0 are calculated using (1). Divide the pixels near the spot color point into several regions (2) Remove the pixels that contain noise from the areas, and calculate the average density for each region using the remaining pixels (3) Highlight the spot color point The principle is to find the special black density through the process of finding the representative density based on specific judgment conditions such as black density and shadow.

FIG. 3 shows an example of the case where pixel data near a spot color point is divided into regions using the method of this invention, and the spot color point coordinates are (
i, j), and shows 5×5 pixel data in the vicinity. Here, this area is a small group of 2x2 pixel data as shown by area AI.
A small group of 4×4=18 areas is created in X5 pixel data (assuming that adjacent areas have a common part), that is, the area (small group) AI is (i-1,
j-2), (i-2j-2n, (i-1, j-1), (
It is made up of four pixel data of (i-1, j-1), but the adjacent small group is, for example, (i, j-2)
, (i-1j-2).

(i, j-1), (i-1, j-1) of a small group region consisting of pixel data whose density is D for each of these 2X2=4 pieces. When the average concentration is R and the standard deviation is σ.

In-DI >Kσ ・・・・・・・・・(1
) However, pixels with a constant value are determined to contain noise and are removed, and the average density of the small group area excluding these noise pixels is calculated. and.

Next, one representative density is calculated based on the determination conditions specific to the spot color point. In other words, if the spot color point is a highlight point, ■The three color densities of B, G, and R are balanced.■B, G, and R
If the two criteria that the average value of the three color densities is the minimum are satisfied, a predetermined calculation is performed from the above-mentioned average densities, and this is determined as the representative density. Next, if the spot color point is a single shadow point, ■The three color densities of B, G, and R are balanced.■B, G,
If the two criteria of determining that the average value of the three color densities of R is the maximum are satisfied, a predetermined calculation is performed from the above-mentioned average density, and this is determined as a representative density. And the feature point is Ha
If there is neither an f-light point nor a single shadow point, the average density of each area (small group) and the area in its vicinity is taken as the representative density.

Figure 4 shows the above logic organized by Gronk.To determine the representative density of a spot color point that does not include noise pixels, first calculate the area of pixel data! 1I21 is performed, and then noise pixels in each area are removed 22. After calculating the average density of each area 23, 4. The representative density calculation 24 is performed under the stability condition of color point hardness 1. The representative density obtained in this way is defined as a special color C degree,
The arithmetic processing described above is performed, and the one-tone table and color correction coefficient are automatically set as output condition setting parameters.

Although the explanation here focuses on noise removal, as mentioned above, the physical deviation between the input coordinates of the digitizer 14 and the coordinates on the input drum l is also calculated as the average density, so this There will be no negative effects due to misalignment.

(Effects of the Invention) As described above, according to the automatic setting method of the output signal processing conditions in the image processing system of the present invention, the spot color black density used for calculation processing does not include noise, and therefore extremely accurate Calculation results can be obtained and output signal processing conditions can be set with high precision.

[Brief explanation of drawings]

Figure 1 is a block diagram showing an embodiment of an image input/output system to which the present invention can be applied, Figure 2 shows a method for generating image processing condition setting parameters, and Figure 3 divides pixels into regions. FIG. 4 is a block diagram showing the logic of the present invention. ■...Input drum, 2...Input color original, 3...
- Logarithmic conversion circuit, 4... A/D converter, 5... Signal processing unit, 6... Network conversion circuit, 7... Laser oscillator,
8... Modulator, 9... Operation control unit, IO... Output drum, 11... Photosensitive material, 12... Microprocessor, 13... Computer, 14... Digitizer, 15...・・Graphic de c spray, 16・
...Console, 21...Region division of pixel data, 2
2... Noise pixel removal for each area, 23... Average density calculation for each area, 24... Representative density calculation. Applicant's agent Yu Yasugata 2+i times

Claims (4)

[Claims] (1) Input each color input density signal from the image input device that separates and reads a color original into the signal processing unit, and outputs the color output density signal as an image after performing each color gradation process on these signals. In a color image input/output system that inputs data to a device, when determining the density of pixel data at the spot color point coordinates on the color document, the density of pixel data at multiple points near the spot color point coordinates is determined, and the pixel data at these multiple points is calculated. After removing pixel data having a density including noise, calculate the average density value of the pixel data of the plurality of points, calculate the representative density of the spot color point from the average density value according to predetermined judgment conditions, and calculate the representative density of the spot color point. 1. A method for automatically setting output signal processing conditions in an image input/output system, characterized in that image processing conditions for each color output density signal are automatically set based on representative density. (2) The spot color point is set as a highlight point, and the three color density signals of B, G, and R at the spot color point are balanced within a predetermined tolerance, and the average value of the three color density signals is within the color original. A method for automatically setting output signal processing conditions in an image input/output system according to claim 1, wherein the determination condition for determining the representative density value from the average density value is that . . (3) The spot color point is a shadow point, and the three color density signals of B, G, and R at the spot color point are balanced within a predetermined tolerance, and the average value of the three color density signals is within the color original. 2. The method for automatically setting output signal processing conditions in an image input/output system according to claim 1, wherein the determination condition for determining the representative density value from the average density value is that the maximum density value is the maximum. (4) Automatic setting of output signal processing conditions in the image input/output system according to claim 1, wherein the image output device converts the color output density signal into a halftone signal and outputs it. Method.