JPS60192986A - Density corrector for image - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a display device capable of storing grayscale images in a continuous memory and displaying them one after another, and particularly relates to a display device capable of storing grayscale images in a continuous memory and displaying them one after another. The present invention relates to an image gradation correction device that can automatically detect tone distribution, correct the density gradation of a gradation image according to the detected content, and display the image as an easy-to-read image.

(b) Prior Art and Problems A conventional display device that displays a gray scale image displays the image as it is according to the gray scale of the image provided from the host device. However, since the original image data is obtained from photographs, cameras, etc., there are large variations in the shading of each original image, and there are some that are thicker and others that are lighter overall, which makes it difficult to display on a display device. In many cases, it is difficult to see. Therefore, in order to make this easier to see, it was often necessary to rely on the image processing program of the host computer. However, when relying on an image processing program, the image data once displayed on the display device must be processed by the operator by giving instructions to the host computer to change the density, and then sent again to the post computer and display device. The processing procedure is complicated and time-consuming because the display device remembers the brightest and darkest density and notifies the host computer to process it. There are drawbacks. Furthermore, when the density adjustment is automatically performed between the display device and the post-computer, there is a drawback that it is inconvenient when the operator wants to know the density state of the original image.

<c> Purpose of the Invention In view of the above drawbacks, the purpose of the present invention is to detect and store the maximum and minimum density values of image data to be displayed;
When modifying and displaying this image data, the maximum and minimum density values are replaced with the maximum and minimum density values that can be displayed by the display device, and the intermediate gray levels are linearly converted and converted into image data that is easy to view. An object of the present invention is to provide an image gradation correction device that can be displayed in a manner similar to that of an image.

(d) Structure of the Invention The structure of the present invention is that in a display device capable of storing and reading out and displaying gradation image information corresponding to gradation level information in a tone memory, the maximum density value of the gradation level of input image data and a density detection means for detecting a minimum density value, a density difference detection means for detecting a density difference between the maximum density value and the minimum density value, and a display based on the density difference and the maximum density difference that can be displayed by the display device. A means for determining the gray level for display, and a table for converting the gray level of the input image data into the gray level for display are provided.

(,e) Embodiments of the Invention The present invention stores the maximum density value and minimum density value of image data, and when displaying information such as a photograph, the original data is too dark or too bright. However, the image in which the difference in shading is difficult to distinguish is linearly corrected using a density conversion table based on the maximum density value and minimum density value that can be displayed by the display device based on an operator's instruction, thereby making the image easy to view.

The figure is a block diagram of a circuit showing one embodiment of the present invention.

Image data is sent to the interface unit 1 via the terminal A from the host device. The image data of the control unit 2 is stored in the image memory 6. Picture 1 image memory 6 is 10 if it is lined up
If the dot memory is 24 x 1024 x 8, the image data can be displayed with 1024 dots vertically and horizontally and 8 bits of density, that is, with a maximum of 256 levels and a zero level difference.

When this image data is stored in the image memory 6, 8-bit grayscale data for one tont of the display point is stored in the control unit 6.
The contents of the maximum value register 3 and the minimum value register 4 are compared under the control of . At this time, if the content of the maximum value register 3 is small, the density value of the gradation data is stored, and if the content of the minimum value register 4 is large, the density value of the gradation data is stored. When data for one screen is stored in the image memo I76 in this way, the maximum density value J of this image data is stored in the maximum value register 3, and the minimum density value j is stored in the minimum value register 4. Stored. The table creation section 5 reads the value J of the maximum value register 3 and the value j of the minimum value register 4, calculates J-j+1=D, calculates D/256=d from this, and stores it. The density conversion table 7 has addresses from 0 to 255, and under the control of the control unit 2 based on the calculation results created by the table creation unit 5, j is written to address 0, and j+d1 is written to address 1.
The number 2 is j+2d, and the number 3 is j-1-3d.

- is written. and j+255 at address 255
d is written. However, at this time, decimal places are rounded down.

The density conversion table 7 created in this manner includes a table for enlarging and converting the density of image data having gray levels from j to J to gray levels from O to 255. The image data stored in the image memory 6 is displayed on the display section 9 under the control of the display control section 8. When the operator sees this and converts the concentration, the terminal A is sent to the control unit 2.
An instruction is given via the interface section 1. The data read out from the image memory 6 under the control of the control unit 2 is converted from the density levels j to J into levels 0 to 255 according to the table prepared in the density conversion table 7, and then written to the image memory 6 again. . The rewritten image data is displayed on the display section 9 under the control of the display control section 8, and is converted into an easy-to-see image having a density expanded to the maximum density difference that can be displayed by the display device.

In addition, by providing multiple sets of image memories 6 to save the original image data, or by changing the maximum and minimum values programmatically, the correction method can be changed and the shading of the image can be changed, making the acid part particularly clear. It is also possible to display the information.

(f) As mentioned in the detailed description of the invention, the present invention is capable of converting an image that is too dark or an image that is too bright to a density that is difficult to view and displaying the image when desired by the operator.

[Brief explanation of the drawing]

The figure is a block diagram of a circuit showing one embodiment of the present invention. 1 is an interface section, 2 is a control section, 3 is a maximum value register, 4 is a minimum value register, 5 is a table creation section, 6 is an image memory, 7 is a density conversion table, 8 is a display control section, 9
is the display section.

Claims (1)

[Claims] In a display device capable of storing and reading out and displaying grayscale image information having grayscale level information in a do/nodo memory, a density detection means for detecting a maximum density value and a minimum density value of the grayscale level of input image data; , a density difference detection means for detecting the density difference between the maximum density value and the minimum density value, a means for determining a gray level for display from the density difference and the maximum density difference that can be displayed by the display device; 1. An image shading correction device comprising: a table for converting a shading level of input image data into a display shading level.