CN117376537A - Gamma rapid correction method for Micro-LED projection display device - Google Patents
Gamma rapid correction method for Micro-LED projection display device Download PDFInfo
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- CN117376537A CN117376537A CN202311521380.9A CN202311521380A CN117376537A CN 117376537 A CN117376537 A CN 117376537A CN 202311521380 A CN202311521380 A CN 202311521380A CN 117376537 A CN117376537 A CN 117376537A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3191—Testing thereof
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3141—Constructional details thereof
- H04N9/315—Modulator illumination systems
- H04N9/3155—Modulator illumination systems for controlling the light source
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3179—Video signal processing therefor
- H04N9/3182—Colour adjustment, e.g. white balance, shading or gamut
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Abstract
The invention discloses a Gamma quick correction method of a Micro-LED projection display device, which can accurately describe the nonlinear relation between an input signal and output brightness by adopting an exponential fitting mode, thereby improving the accuracy of Gamma correction, simplifying the calculation process and improving the speed of Gamma correction; the invention can improve the Gamma correction speed while ensuring the Gamma correction precision, and can adapt to different display conditions and user requirements.
Description
Technical Field
The invention relates to the technical field of Micro-LED projection display, in particular to a Gamma rapid correction method of a Micro-LED projection display device.
Background
A Micro-LED projection display device is a display apparatus that projects an image onto a screen or other object through a projection optical system using a Micro-LED array as a light source. The Micro-LED projection display device has the advantages of high brightness, high contrast, low power consumption, long service life and the like, and is suitable for various occasions such as home theatres, commercial exhibition, education training and the like.
However, there are some problems in Micro-LED projection display devices, one of which is Gamma correction, which refers to non-linear adjustment of brightness of an image so that brightness distribution of the image conforms to the perception characteristics of human eyes. Because the relation between the brightness and the voltage of the Micro-LED array is not linear but accords with the power function relation, the voltage of the Micro-LED array needs to be Gamma corrected so as to ensure the color restoration and detail representation of the image.
Currently, there are two common Gamma correction methods: one is to add a Gamma correction circuit into a driving circuit of a Micro-LED array to regulate the voltage of each Micro-LED unit; and the other is to add a Gamma correction module into the image signal processor, perform Gamma correction on the input image signal and output the image signal to the Micro-LED array. Both methods require pre-measuring a relation curve between brightness and voltage of the Micro-LED array, establishing a corresponding Gamma correction curve or table, and then adjusting the voltage or signal according to the Gamma correction curve or table.
The Gamma correction method in the prior art has the following main defects: (1) In the prior art, the Gamma correction method needs to add an additional hardware circuit in a driving circuit or an image signal processor of the Micro-LED array for adjusting the voltage or signal of each Micro-LED unit, which increases the cost and complexity and also affects the performance and stability of the Micro-LED array; (2) In the prior art, the Gamma correction method needs to measure and establish a relation curve or table between the brightness and the voltage of the Micro-LED array in advance, and adjust the voltage or signal according to the curve or table, which reduces the efficiency and flexibility, and is also influenced by factors such as the manufacturing process, the aging process, the ambient temperature and the like of the Micro-LED array, so that the Gamma correction curve or table is invalid or outdated; (3) In the prior art, since a discrete Gamma correction curve or table is adopted and the relation curve between the actual brightness and the voltage is continuous, interpolation errors or quantization errors may occur in the Gamma correction process, resulting in degradation of image quality, especially in low gray level. Therefore, there is a need for a method for performing Gamma correction on a Micro-LED projection display device rapidly and accurately.
Disclosure of Invention
The invention relates to a Gamma quick correction method of a Micro-LED projection display device, which solves the technical problems of realizing the Gamma correction of the Micro-LED projection display device under the conditions of not adding a hardware circuit, not presetting a Gamma correction curve or table and not generating interpolation errors or quantization errors so as to ensure the color reduction and detail representation of an image. The Gamma correction method based on the standard gray-scale image and the photoelectric sensor is controlled by software, so that the problems are effectively solved, and the Gamma of the Micro-LED projection display device is rapidly corrected.
The invention realizes the above purpose through the following technical scheme:
a Gamma rapid correction method of a Micro-LED projection display device comprises the following steps:
the method comprises the following steps:
step 1, connecting a Micro-LED projection display device to Gamma correction software, wherein the Gamma correction software is used for controlling input and output signals of the Micro-LED projection display device and calculating and storing Gamma correction parameters;
step 2, selecting a standard gray-scale image from Gamma correction software, and sending the standard gray-scale image to a Micro-LED projection display device for projection; the Gamma correction software sequentially sends test images with different gray scales, and records the brightness and color coordinate values corresponding to each gray scale through a photometer; drawing a relation curve between the input gray level and the output brightness to obtain an original gamma curve of the projection system;
step 3, selecting a target gamma value to represent the ideal brightness response characteristic of the Micro-LED projection display device; the proper gamma value can also be selected according to the actual demand and the environmental condition;
step 4, fitting an original gamma curve by using an exponential function, and adopting the following functions: y=a·ebx
Minimizing the error of f (x) from the original gamma curve;
step 5, converting the exponential function relation into a logarithmic function relation, and storing the logarithmic function relation in a memory;
step 6, receiving an input signal of an image to be corrected and converting the input signal into an logarithmic value;
and 7, calculating the output brightness corresponding to the image to be corrected according to the logarithmic function relation, and converting the output brightness into a linear value.
The Gamma correction software provides various image enhancement and beautification options through a built-in image processing function, including sharpening, denoising, contrast adjustment and filter effect; and the software is internally provided with a built-in projection test function to provide various projection test images and videos, including gray-scale images, color stripe images, grid images and dynamic videos, for detecting and evaluating the performance and quality of the projection display device.
In the step 4, a nonlinear least square method is adopted to perform exponential function fitting.
Further, in the step 5, natural logarithms are taken from two sides of the exponential function relation, and a logarithmic function relation in the following form is obtained: lny = lna +b·x
Where lny denotes the logarithmic value of the output luminance, lna and b are parameters of the logarithmic function.
In step 6, an image sensor or other image acquisition equipment is used to receive an input signal of an image to be corrected and transmit the input signal to a memory in the form of a digital signal; then, natural logarithm operation is carried out on the input signal to obtain a corresponding logarithm value.
In the step 7, the logarithmic value of the output brightness corresponding to each pixel point of the image to be corrected is calculated according to the logarithmic function relation, and is transmitted to the memory in the form of a digital signal; then, the logarithmic value of the output brightness is subjected to inverse natural logarithmic operation to obtain a corresponding linear value.
The invention has the beneficial effects that:
according to the Gamma rapid correction method of the Micro-LED projection display device, the nonlinear relation between the input signal and the output brightness can be accurately described by adopting an exponential fitting mode, so that the Gamma correction precision is improved, the calculation process can be simplified, and the Gamma correction speed is improved; meanwhile, the invention adopts software to control and a sensor to transmit the intensity of ambient light, can acquire the illumination condition of the current display environment in real time, and dynamically adjusts according to the illumination condition. The invention can improve the Gamma correction speed while ensuring the Gamma correction precision, and can adapt to different display conditions and user requirements.
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In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following description will briefly explain the practical drawings required in the embodiments or the prior art description, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of the present invention.
FIG. 2 is a graph illustrating Gamma correction according to the present invention.
FIG. 3 is a graph of the fitted parameter values of an example of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be described in detail below. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, based on the examples herein, which are within the scope of the invention as defined by the claims, will be within the scope of the invention as defined by the claims.
In any embodiment, as shown in fig. 1 to 3, a Gamma fast correction method of a Micro-LED projection display device of the present invention includes:
(1) The Micro-LED projection display device was connected to a Gamma correction software designed. The software is used for controlling input and output signals of the Micro-LED projection display device and calculating and storing Gamma correction parameters. The software can provide various image enhancement and beautification options such as sharpening, denoising, contrast adjustment, filter effect and the like for the built-in image processing function, and provide various projection test images and videos such as gray-scale images, color stripe images, grid images, dynamic videos and the like for the built-in projection test function for detecting and evaluating the performance and quality of the projection display device.
(2) And selecting a standard gray-scale image in the software, and sending the standard gray-scale image to a Micro-LED projection display device for projection. The software sequentially sends test images with different gray scales, and the brightness and color coordinate values corresponding to each gray scale are recorded through a photometer. And drawing a relation curve between the input gray level and the output brightness to obtain an original gamma curve of the projection system.
(3) A target gamma value is selected to represent the desired luminance response characteristics of the Micro-LED projection display device. And proper gamma value can be selected according to actual requirements and environmental conditions.
(4) An exponential function is used to fit the original gamma curve, employing the function: y=a·ebx
So that the error of f (x) from the original gamma curve is minimized. And adopting a nonlinear least square method to perform exponential function fitting.
(5) The exponential function relation is converted into a logarithmic function relation and stored in a memory. Specifically, natural logarithms can be taken on both sides of the exponential function relationship to obtain a logarithmic function relationship of the form:
lny＝lna+b·x
where lny denotes the logarithmic value of the output luminance, lna and b are parameters of the logarithmic function. As the perception function of human eyes on brightness is similar to an exponential function, the fitting degree of the display image of the Micro-LED projection display device and subjective perception of human eyes can be improved to a certain extent by adopting a logarithmic fitting method.
(6) An input signal of an image to be corrected is received and converted into an logarithmic value. Specifically, an image sensor or other image acquisition device may be used to receive an input signal of an image to be corrected and transmit it in the form of a digital signal into a memory. Then, natural logarithm operation is carried out on the input signal to obtain a corresponding logarithm value.
(7) And calculating the output brightness corresponding to the image to be corrected according to the logarithmic function relation, and converting the output brightness into a linear value. And calculating the logarithmic value of the output brightness corresponding to each pixel point of the image to be corrected according to the logarithmic function relation, and transmitting the logarithmic value to a memory in the form of a digital signal. Then, the logarithmic value of the output brightness is subjected to inverse natural logarithmic operation to obtain a corresponding linear value.
Taking a projection complete machine as an example for explanation: the parameters of the projection complete machine system are as follows: maximum brightness of 1000cd/m 2 Minimum luminance of 0.01cd/m 2 ：
(1) The Gamma correction may use 256 gray-scale values as input signals, with the corresponding output brightness being an integer value between 0 and 255.
(2) Selecting a gamma value of 2.2 as an ideal CRT display brightness response value for the step (3);
(3) In the corresponding steps (4) and (5), a=10 and b=0.02 are taken in this example;
(4) And (3) performing exponential fitting on the least square method in the matlab by adopting the scipy.optimal.cure_fit () function in the step (4).
(5) Corresponding to step (6), if an image pixel to be corrected with an input signal of 128 is received, the corresponding logarithmic value is ln128=4.85.
(6) And (7) correspondingly, if the logarithmic value of the output brightness corresponding to the pixel point of the image to be corrected is lny =5.06 according to the logarithmic function relation, the corresponding linear value is y=e5.06=157.
The foregoing is merely illustrative of the present invention, and the present invention is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims. In addition, the specific features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various possible combinations are not described further. Moreover, any combination of the various embodiments of the invention can be made without departing from the spirit of the invention, which should also be considered as disclosed herein.
Claims (6)
1. A Gamma rapid correction method of a Micro-LED projection display device is characterized by comprising the following steps:
step 1, connecting a Micro-LED projection display device to Gamma correction software, wherein the Gamma correction software is used for controlling input and output signals of the Micro-LED projection display device and calculating and storing Gamma correction parameters;
step 2, selecting a standard gray-scale image from Gamma correction software, and sending the standard gray-scale image to a Micro-LED projection display device for projection; the Gamma correction software sequentially sends test images with different gray scales, and records the brightness and color coordinate values corresponding to each gray scale through a photometer; drawing a relation curve between the input gray level and the output brightness to obtain an original gamma curve of the projection system;
step 3, selecting a target gamma value to represent the ideal brightness response characteristic of the Micro-LED projection display device; the proper gamma value can also be selected according to the actual demand and the environmental condition;
step 4, fitting an original gamma curve by using an exponential function, and adopting the following functions:
y＝a·ebx
minimizing the error of f (x) from the original gamma curve;
step 5, converting the exponential function relation into a logarithmic function relation, and storing the logarithmic function relation in a memory;
step 6, receiving an input signal of an image to be corrected and converting the input signal into an logarithmic value;
and 7, calculating the output brightness corresponding to the image to be corrected according to the logarithmic function relation, and converting the output brightness into a linear value.
2. The Gamma quick correction method of a Micro-LED projection display device according to claim 1, wherein the Gamma correction software provides a plurality of image enhancement and beautification options including sharpening, denoising, contrast adjustment and filter effect through a built-in image processing function; and the software is internally provided with a built-in projection test function to provide various projection test images and videos, including gray-scale images, color stripe images, grid images and dynamic videos, for detecting and evaluating the performance and quality of the projection display device.
3. The Gamma fast correction method for Micro-LED projection display device according to claim 1, wherein in the step 4, an exponential function fitting is performed by using a nonlinear least square method.
4. The method for rapid Gamma correction of Micro-LED projection display device according to claim 1, wherein in step 5, natural logarithms are taken from both sides of the exponential function relationship to obtain a logarithmic function relationship of the form:
lny＝lna+b·x
where lny denotes the logarithmic value of the output luminance, lna and b are parameters of the logarithmic function.
5. The method for rapidly correcting Gamma of a Micro-LED projection display device according to claim 1, wherein in the step 6, an image sensor or other image acquisition equipment is used to receive an input signal of an image to be corrected and transmit the input signal to a memory in the form of a digital signal; then, natural logarithm operation is carried out on the input signal to obtain a corresponding logarithm value.
6. The Gamma quick correction method of a Micro-LED projection display device according to claim 1, wherein in the step 7, a logarithmic value of output brightness corresponding to each pixel of an image to be corrected is calculated according to a logarithmic function relation, and is transmitted to a memory in a digital signal form; then, the logarithmic value of the output brightness is subjected to inverse natural logarithmic operation to obtain a corresponding linear value.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117912383A (en) * | 2024-03-20 | 2024-04-19 | 四川启睿克科技有限公司 | Method for testing brightness uniformity of flat panel display equipment |
| CN117912383B (en) * | 2024-03-20 | 2024-05-31 | 四川启睿克科技有限公司 | Method for testing brightness uniformity of flat panel display equipment |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117912383A (en) * | 2024-03-20 | 2024-04-19 | 四川启睿克科技有限公司 | Method for testing brightness uniformity of flat panel display equipment |
| CN117912383B (en) * | 2024-03-20 | 2024-05-31 | 四川启睿克科技有限公司 | Method for testing brightness uniformity of flat panel display equipment |
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