JPH04136986A - Multilevel picture display controller - Google Patents

Abstract

PURPOSE:To minimize the reading out of display memory for automatically producing look-up table data for obtaining a display signal having optimum gradation properties by addressing the display memory with a specific reading out address set in advance. CONSTITUTION:The contents of the address of a display memory read out address 3 are read out from display memory 4, outputted as display memory output data 5, sent to a minimum/maximum values detecting circuit 6 to be used for detecting the minimum/maximum values, and the detected minimum/ maximum values 7 is corrected with a correcting value 8 by a minimum/ maximum values correcting circuit 9, and outputted into a look-up table producing circuit 11 as correction data 10. On the other hand, a reading out control circuit 1 carries out data reading out control for carrying out a display from display memory 6, as well, allows the display memory 6 to output display memory output data 5, and sends it to a gradation conversion look-up table 13. In the look-up table 13, the gradation conversion of the inputted display memory output data 5 is carried out with look-up table data 12 written in advance, and display data 14 is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a multi-valued image display control device, and more particularly to a multi-valued image display control device that outputs a display signal obtained by gradation-converting data to be displayed.

[Prior Art] ゛Conventionally, this type of multivalued image display control device needs to automatically create lookup table data for gradation conversion to achieve optimal display. All data within a predetermined area is read out, the minimum and maximum values are found, and lookup table data is created based on these values.

[Problem to be solved by the invention]

The conventional multivalued image display control device described above needs to automatically create lookup table data for gradation conversion to obtain an optimal display. Since all the data was read out, the minimum and maximum values were found, and lookup table data was created based on those values, it was necessary to process a large amount of data, and in order to obtain the optimal display. The disadvantage is that it takes a long time to perform the process, and when it is performed in a part of the area, it is difficult to obtain look-up table data for optimal display because data outside the area is not reflected.

[Means to solve the problem]

A multivalued image display control device of the present invention includes a display memory for storing data to be displayed, an address output means for outputting a specific read address set in advance for the display memory, and read data from the display memory. a detection means for detecting the maximum and minimum values of the detection means; a correction means for correcting the minimum and maximum values detected by the detection means at a preset ratio; lookup table creation means for creating lookup table data for converting an input range of values into an output range from a minimum value to a maximum value, and writing the lookup table data as conversion data and outputting the output of the display memory. It is configured to include a look-up table for gradation conversion.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

A read control circuit 1 controls a read address output circuit 2 and outputs a display memory read address 3 and a display memory 4.
, and controls the minimum value/maximum value detection circuit 6 to detect the minimum and maximum values of the data in the display memory 4. Then, the contents of the display memory read address 3 are read from the display memory 4, output as display memory output data 5, and sent to the minimum/maximum value detection circuit 6, which is used to detect the minimum and maximum values. is,
The detected minimum/maximum value 7 is corrected by a correction value 8 in a minimum/maximum value correction circuit 9 and inputted as correction data 10 to a look-up table creation circuit 11. The lookup table creation circuit 11 creates and outputs lookup table data 12 based on the correction data E0, and writes it into the gradation conversion lookup table 13. On the other hand, the read control circuit 1 also performs data read control for display from the display memory 6, outputs display memory output data 5, and sends it to the gradation conversion lookup table 13. The gradation conversion lookup table 13 performs gradation conversion on the input display memory output data 5 using the previously written lookup table data 12, and outputs display data 14. The display data 14 is further outputted to the display signal 1 by the display signal output circuit 15.
6 and output.

In the above configuration, the case where the data stored in the display memory 4 is composed of 16×16 pixels as shown in FIG. 2(a) will now be described.

The number attached to each pixel is the address of the display memory 4. If the read address output circuit 2 is specified in advance to output the read address 3 in the order shown in FIG. The data shown in b) are sequentially output, and the contents of the addresses in the circles in FIG. 2(a) are read out from the display memory 4 and output as display memory output data 5. If the minimum value detected by the minimum value/maximum value detection circuit 6 is A and the maximum value is B, then the minimum value is corrected to A' and the maximum value is corrected to B' by the minimum value/maximum value correction circuit 9. hand,
Lookup table creation circuit 1 as correction data 10
1, the lookup table creation circuit 11 creates lookup table data 12 having the input/output relationship shown in FIG.
written to.

〔Effect of the invention〕

As explained above, the present invention selectively reads limited data by addressing the display memory using a specific read address set in advance, detects the minimum value and maximum value therein, and further By creating lookup table data using the corrected data and converting the gradation of the displayed data using the lookup table, lookup table data is automatically created to obtain a display signal with optimal gradation characteristics. It is possible to minimize the display memory readout required to create the display, and by correcting the detected minimum and maximum values, the disadvantage of not reflecting data that is not subject to detection is improved, and the display can be displayed in a short time. This has the effect that an optimal display signal can be obtained.

Up table creation circuit, 13... Gradation conversion look up table, 15... Display signal output circuit.

Claims (1)

[Claims] A display memory that stores display data, an address output unit that outputs a specific read address set in advance for the display memory, and a detection unit that detects the maximum and minimum values of the read data from the display memory. and a correction means for correcting the minimum and maximum values detected by the detection means at a predetermined rate; and a look-up table for writing look-up table data as conversion data to convert the output of the display memory into gradation. A multivalued image display control device characterized by: