CN102903329A - Light emitting diode (LED) display screen brightness regulating method without loss of low gray scale - Google Patents

Abstract

The invention provides a light emitting diode (LED) display screen brightness regulating method without loss of low gray scale, and mainly solves the problem that a low gray scale effect of the LED display screen is poor because the low gray scale is easy to lose when the brightness of an LED display screen is regulated by a method in the prior art. The LED display screen brightness regulating method without the loss of the low gray scale comprises the following steps of: (1) performing reverse gamma correction on 8-bit gray scale data of input video signals and mapping the 8-bit gray scale data onto 16-bit gray scale data; and (2) reducing the weight sub-field number of the highest bit in the 16-bit gray level data according to brightness efficiency required to be reduced, namely finishing brightness regulation of an LED display screen. By the scheme, the brightness efficiency of the LED display screen is reduced by changing a gray scale arranging mode, so that the brightness of a screen body is reduced.

Description

Do not lose the LED display brightness adjusting method of low gray scale

Technical field

The present invention relates to a kind of LED display brightness adjusting method that does not lose low gray scale, the method is mainly used in LED display control system field.

Background technology

The problem that low gray scale is lost can appear in existing LED display control system when reducing the brightness of LED display, cause the display effect variation.

Because the linear response characteristic of LED, present LED display control need to be carried out doing the gray scale realization after inverse gamma correction is mapped to 16 gradation datas to 8 gray scales of input again.If x is 8 input gray level data, codomain is 0 to 255, y to be 16 gradation datas behind the inverse gamma correction, and γ is gamma value, and codomain is 1 to 4, and mapping relations are as follows:

$y=65535*{\left(\frac{x}{255}\right)}^{\mathrm{\γ}}$

When needs reduced the brightness of LED display, existing technology was that the y value after the anti-gamma directly is multiplied by a brightness number percent, such as needs brightness is dropped to 50%, just with y on duty 0.5.But the problem that this way can cause has: the y value of 1. less x value mapping is 0, and the result who causes these gray levels to realize can't light; 2. many identical y values of x value mapping cause these gray levels to realize that effect is identical; Above-mentioned two problems can cause the low gradation effect variation of display screen.

Summary of the invention

The invention provides a kind of LED display brightness adjusting method that does not lose low gray scale, the easy low gray scale of loss when mainly having solved prior art LED display being carried out brightness regulation, thus cause the problem of the low gradation effect variation of LED display.

Concrete technical solution of the present invention is as follows:

The LED display brightness adjusting method that this does not lose low gray scale may further comprise the steps:

1) 8 gradation datas of incoming video signal is carried out inverse gamma correction and be mapped to 16 gradation datas;

2) luminance efficiency that reduces as required, the weight subfield number of reduction the highest bit position in 16 gradation datas of step 1 processing gained, all the other bit position weight subfield numbers reduce on year-on-year basis, former right to occupation baryon number of fields is 1 bit position, its weight subfield number is constant, finish the adjusting to luminance efficiency, namely finished the brightness regulation of LED display.

In the above-mentioned steps 2, the bit position is that the bit0 position is to the bit15 position, the highest bit position is the bit15 position, bit15 position, the highest bit position former weight subfield number is 32, bit14 position former weight subfield number is 16 ... bit10 position former weight subfield number is that 1, bit9 position former weight subfield number is 1 ... bit0 position former weight subfield number is 1; Weight subfield number average reduces by one times, and the highest bit position weight subfield number after the reduction becomes 16, and by that analogy, luminance efficiency reduces, and finishes the brightness regulation to LED display.

In the above-mentioned steps 2, the bit position is that the bit0 position is to the bit15 position, the highest bit position is the bit15 position, bit15 position, the highest bit position former weight subfield number is 32, bit14 position former weight subfield number is 16 ... bit10 position former weight subfield number is that 1, bit9 position former weight subfield number is 1 ... bit0 position former weight subfield number is 1; Weight subfield number average reduces twice, and the highest bit position weight subfield number after the reduction becomes 8, and by that analogy, luminance efficiency reduces, and finishes the brightness regulation to LED display.

The invention has the advantages that:

Thereby the scheme that the present invention proposes is the luminance efficiency that reduces LED display by changing the gray scale arranged mode reduces the brightness of shielding body.This mode is not to the y luminance factor on duty after the anti-gamma, so the problem of the low gray scale of Dimming loss in the existing scheme can not occur.

Embodiment

Describe in detail below in conjunction with the technical scheme of specific embodiment to invention:

At present general LED display adopts on-off formula constant-current driven chip driving LED screen body, gradation data y value behind 16 the anti-gamma is to realize by the subfield arranged mode, each subfield is sent certain 1 of gradation data, realizes the weight of this 1 bit data by the opening time of control driving chip.Common arranged mode is as follows:

Bit	Take the subfield number	Weight (opening time accounts for the ratio of a subfield) when this bit realizes
			15	32	1
14	16	1
			13	8	1
12	4	1
			11	2	1
10	1	1

9	1	1/2
			8	1	1/4
7	1	1/8
			6	1	1/16
5	1	1/32
			4	1	1/64
3	1	1/128
			2	1	1/256
1	1	1/512
			0	1	1/1024

(gray scale arranged mode 1)

This arranged mode realizes that a gray scale need to amount to 73 subfields, and gradation data is to the maximum at 65535 o'clock, and (each bit that is 16bit is 1) driving chip adds up to opening time to take 64 subfields, and the luminance efficiency of this arranged mode is:

$\mathrm{\η}=\frac{64}{73}=87.6\%$

The method of Dimming efficient provided by the invention is to reduce the highest bit position weight subfield number, and the highest bit of upper table position weight is 32 subfields, and when it became 16 subfield, its luminance efficiency was:

$\mathrm{\η}=\frac{32}{42}=76.2\%$

Bit	Take the subfield number	Weight (opening time accounts for the ratio of a subfield) when this bit realizes
			15	16	1
14	8	1
			13	4	1
12	2	1
			11	1	1
10	1	1/2
			9	1	1/4

8	1	1/8
			7	1	1/16
6	1	1/32
			5	1	1/64
4	1	1/128
			3	1	1/256
2	1	1/512
			1	1	1/1024
0	1	1/2048

(gray scale arranged mode 2)

When it became 16 subfield, its luminance efficiency was:

$\mathrm{\η}=\frac{16}{27}=59.2\%$

Bit	Take the subfield number	Weight (opening time accounts for the ratio of a subfield) when this bit realizes
			15	8	1
14	4	1
			13	2	1
12	1	1
			11	1	1/2
10	1	1/4
			9	1	1/8
8	1	1/16
			7	1	1/32
6	1	1/64
			5	1	1/128
4	1	1/256
			3	1	1/512
2	1	1/1024

1	1	1/2048
			0	1	1/4096

(gray scale arranged mode 3)

By being used in conjunction with this two kinds of methods, can change luminance efficiency, a plurality of gray scale arrangement patterns can be set like this realize a plurality of brightness commonly used.When certain brightness of needs, call and change the gray scale arrangement pattern and get final product.

Claims (3)

1. one kind is not lost the LED display brightness adjusting method that hangs down gray scale, it is characterized in that: may further comprise the steps:

1) 8 gradation datas of incoming video signal is carried out inverse gamma correction and be mapped to 16 gradation datas;

2) luminance efficiency that reduces as required, the weight subfield number of reduction the highest bit position in 16 gradation datas of step 1 processing gained, all the other bit position weight subfield numbers reduce on year-on-year basis, former right to occupation baryon number of fields is 1 bit position, its weight subfield number is constant, finish the adjusting to luminance efficiency, namely finished the brightness regulation of LED display.

2. the LED display brightness adjusting method that does not lose low gray scale according to claim 1, it is characterized in that: in the described step 2, the bit position is that the bit0 position is to the bit15 position, the highest bit position is the bit15 position, bit15 position, the highest bit position former weight subfield number is 32, bit14 position former weight subfield number is 16 ... bit10 position former weight subfield number is that 1, bit9 position former weight subfield number is 1 ... bit0 position former weight subfield number is 1; Weight subfield number average reduces by one times, and the highest bit position weight subfield number after the reduction becomes 16, and by that analogy, luminance efficiency reduces, and finishes the brightness regulation to LED display.

3. the LED display brightness adjusting method that does not lose low gray scale according to claim 2, it is characterized in that: in the described step 2, the bit position is that the bit0 position is to the bit15 position, the highest bit position is the bit15 position, bit15 position, the highest bit position former weight subfield number is 32, bit14 position former weight subfield number is 16 ... bit10 position former weight subfield number is that 1, bit9 position former weight subfield number is 1 ... bit0 position former weight subfield number is 1; Weight subfield number average reduces twice, and the highest bit position weight subfield number after the reduction becomes 8, and by that analogy, luminance efficiency reduces, and finishes the brightness regulation to LED display.