CN-122002013-A - Speckle eliminating method and laser display system

Abstract

The invention discloses a speckle eliminating method and a laser display system, and belongs to the field of laser display. In order to reduce the influence of speckle, the invention shoots the characteristic map and the white map in the projection area through the camera, wherein the characteristic map is used for establishing projection area extraction information, the projection area in the image shot by the camera is conveniently extracted subsequently, the white map is used for extracting the noise map according to the distribution characteristics of the pixel values of the local area, and then whether the noise adding operation is carried out on the output image of the laser display system is judged according to the noise map and the communication area, so that the purpose of inhibiting the speckle is achieved. The invention can improve the influence of laser speckle on the visual imaging effect without changing the curtain or the optical structure.

Inventors

• NING ZHONG
• YU JINQING
• RAN PENG
• WANG XIN

Assignees

• 极米科技股份有限公司

Dates

Publication Date

20260508

Application Date

20241108

Claims (20)

1. 1. A speckle removing method, comprising: The laser display system projects a first image to the projection area, at the moment, an image containing the projection area of the laser display system is acquired, the projection area in the image is extracted, and the projection area in the image after conversion processing is obtained after conversion processing operation, wherein the projection area in the image after conversion processing is the same as the projection resolution of the laser display system; Acquiring a pixel value average value of a whole or partial area of a projection area in the transformed image relative to a first channel, and extracting a noise figure relative to the first channel by utilizing the pixel value average value relative to the first channel; And if the first pixel value and the second pixel value exist in the communication area, and the noise diagram in the first channel indicates that the first pixel value and the second pixel value are both in the noise area, adding noise to the first pixel value, and adding equal amount of noise to the second pixel value in the opposite direction.
2. 2. The speckle removing method of claim 1, wherein: The first image is a solid color image.
3. 3. The speckle removing method according to claim 2, characterized in that: the first image is one of a white image, a red image, a green image and a blue image.
4. 4. A speckle removing method according to claim 1 or 2 or 3, characterized in that: The transformation processing operation is an interpolation operation or an image resolution compression operation.
5. 5. The speckle removing method of claim 1, wherein: The obtaining the pixel value average value of the whole or partial area of the projection area in the image after the transformation processing with respect to the first channel, and extracting the noise figure with respect to the first channel by using the pixel value average value with respect to the first channel specifically comprises the following steps: dividing the projection area in the transformed image into a plurality of local areas, obtaining the average value of the pixel values of each local area in the first channel, and extracting the noise figure in the first channel by using the average value of the pixel values of each local area in the first channel, or And acquiring a mean value of the pixel values of the whole projection area in the transformed image in relation to the first channel, and extracting a noise figure in relation to the first channel by using the mean value of the pixel values of the whole projection area in relation to the first channel.
6. 6. The speckle removing method according to claim 3 or 5, characterized in that: Before the first image is projected, the laser display system projects a feature map to a projection area, at the moment, an image containing the projection area of the laser display system is acquired, and projection area extraction information is established; After the laser display system projects the first image to the projection area, the projection area in the image is extracted according to the information extracted from the projection area.
7. 7. The speckle removing method of claim 6, wherein: acquiring an image containing a projection area of a laser display system through a camera; the projection area extracts information, specifically, a mapping relation between an image captured by a camera and an original shot projection area, wherein the original shot projection area refers to an imaging area occupied by the projection area in the image captured by the camera.
8. 8. The speckle removing method of claim 7, wherein: Extracting information according to the projection area, wherein the extraction of the projection area in the image specifically comprises the steps of obtaining the projection area of the original shooting according to the mapping relation between the image captured by the camera and the projection area of the original shooting after obtaining the image captured by the camera, and taking the projection area as the projection area in the image.
9. 9. The speckle removing method according to claim 1 or 2 or 3 or 5 or 7 or 8, characterized in that: for any pixel value in any local area related to the first channel, if the any pixel value is greater than the average t1 time or less than the average t2 time of the pixel value in any local area related to the first channel, setting an indication noise area mark at a position related to the any pixel value in a noise diagram related to the first channel, wherein t1 is greater than 1, t2 is less than 1 and greater than 0.
10. 10. The speckle removing method of claim 9, wherein: the first channel is a red channel, a green channel, or a blue channel.
11. 11. The speckle removing method of claim 10, wherein: And after the noise adding is carried out on all channels of the output image of the laser display system, obtaining an updated frame image and applying the updated frame image to a projection imaging process of the laser display system.
12. 12. The speckle removing method according to claim 1 or 2 or 3 or 5 or 7 or 8 or 10 or 11, characterized in that: the first pixel value is positioned in a current frame image output by the laser display system; And if the first pixel value is the same as two pixel values in a first channel in the first two frames or the second two frames of the current frame of image output by the laser display system, adding noise to the first pixel value, wherein the two pixel values in the first channel in the first two frames or the second two frames of image and the first pixel value have the same coordinate value in the frame image where each pixel value is located.
13. 13. The speckle removing method of claim 12, wherein: and adding the noise value added to the first pixel value to the two noise values added to the two pixel values in the first channel in the first two frames of the current frame image or the last two frames of the current frame image output by the laser display system, wherein the noise value added to the first pixel value is equal to zero.
14. 14. The speckle removing method of claim 12, wherein: When the noise adding operation is performed only on one pixel value of the two pixel values in the first channel in the first two frames of the current frame image or the last two frames of the current frame image output by the laser display system, the noise value added in the noise adding operation is added to the noise value added to the first pixel value, and the noise value added to the first pixel value is equal to zero.
15. 15. The speckle removing method of claim 12, wherein: and if at least one of the first pixel value and two pixel values in a first channel in the first two frames or the second two frames of the current frame of image output by the laser display system is different, not adding noise to the first pixel value.
16. 16. The speckle removing method of claim 15, wherein: When the noise adding or non-noise adding process is completed on the current frame image, the next frame image of the current frame image is used as a new current frame image, and the same noise adding or non-noise adding process method is applied to the new current frame image.
17. 17. The speckle removing method according to claim 1 or 2 or 3 or 5 or 7 or 8 or 10 or 11, characterized in that: the first pixel value is positioned in a first channel of a current frame image output by the laser display system, the third pixel value is positioned in a first channel of a frame image which is a later frame image of the current frame image, the fourth pixel value is positioned in a first channel of a frame image which is a later frame image, and the first pixel value, the third pixel value and the fourth pixel value have the same coordinate value in the frame image where each pixel value is positioned; When the first pixel value, the third pixel value and the fourth pixel value are equal, a noise adding operation is performed on the first pixel value, the third pixel value and the fourth pixel value, and the sum of the values of the added noise is equal to zero.
18. 18. The speckle removing method of claim 17, wherein: when the first, third and fourth pixel values are not equal, the noise adding operation is not performed on the first, third and fourth pixel values.
19. 19. The speckle removing method of claim 18, wherein: And after the noise adding or noise not adding treatment is completed on the current frame image, the next frame image of the current frame image and the next frame image of the next frame image, processing three frame images after the next frame image of the next frame image according to the same noise adding or noise not adding treatment mode.
20. 20. The speckle removing method according to any one of claims 13 to 16, 18 to 19, characterized in that: the pixel values on which the noise adding operation is performed are all located in the connected region and are in the noise region.

Description

Speckle eliminating method and laser display system Technical Field The invention relates to the field of laser display, in particular to a speckle eliminating method and a laser display system. Background Laser speckle refers to the formation of a multitude of individual scattering wavelets after reflection from or transmission through a translucent medium when laser light impinges on a rough surface (e.g., paper, wall, curtain, etc.), which wavelets coherently superimpose in space to form randomly distributed bright and dark spots, or interference patterns, known as speckle, in the image plane. The size, shape and intensity distribution of the speckles are irregular. The current household intelligent projection equipment generally adopts a laser light source, and the laser light source has high coherence, namely the characteristics of frequency, phase and the like of laser light waves are highly consistent in space and time, and the coherence brings the advantages of high brightness, high color gamut and high stability to image transmission. The coherence of the light source, optically rough surfaces, etc. are important causes of laser speckle. The main schemes for solving the speckle are divided into two types, namely (1) curtain dithering and (2) light source dithering. For example, in the prior art 1, the curtain brightness and contrast are improved by the special curtain composition and structure, and the laser speckle is suppressed. In the prior art 2, four laser beams which are different in emergent optical path difference and are not coherent in any two types are emitted through different light-transmitting pieces, so that the self-coherence phenomenon of emitted laser is weakened, and laser speckles are further weakened. In the prior art 1, CN114075793A, a projection curtain surface structure for resisting laser speckle and a preparation method thereof; Prior art 2, cn208506389u, laser speckle handling device and laser projection device. However, prior art 1 requires changing or customizing the curtain and is often expensive, and prior art 2 requires changing the optical structure, which on the one hand requires increasing hardware costs, and on the other hand is not versatile or applicable in some scenarios, such as where existing hardware conditions cannot be modified. Based on the above, the invention provides a scheme for eliminating speckle without modifying a curtain or an optical structure. Disclosure of Invention In order to alleviate or partially alleviate the above technical problem, the solution of the present invention is as follows: in one aspect, the invention discloses a speckle elimination method, comprising: The laser display system projects a first image to the projection area, at the moment, an image containing the projection area of the laser display system is acquired, the projection area in the image is extracted, and the projection area in the image after conversion processing is obtained after conversion processing operation, wherein the projection area in the image after conversion processing is the same as the projection resolution of the laser display system; Acquiring a pixel value average value of a whole or partial area of a projection area in the transformed image relative to a first channel, and extracting a noise figure relative to the first channel by utilizing the pixel value average value relative to the first channel; And if the first pixel value and the second pixel value exist in the communication area, and the noise diagram in the first channel indicates that the first pixel value and the second pixel value are both in the noise area, adding noise to the first pixel value, and adding equal amount of noise to the second pixel value in the opposite direction. Further, the first image is a solid color map. Further, the first image is one of a white image, a red image, a green image and a blue image. Further, the transformation processing operation is an interpolation operation or an image resolution compression operation. Further, the acquiring the pixel value average value of the whole or partial area of the projection area in the transformed image with respect to the first channel, and extracting the noise figure with respect to the first channel by using the pixel value average value with respect to the first channel specifically includes: dividing the projection area in the transformed image into a plurality of local areas, obtaining the average value of the pixel values of each local area in the first channel, and extracting the noise figure in the first channel by using the average value of the pixel values of each local area in the first channel, or And acquiring a mean value of the pixel values of the whole projection area in the transformed image in relation to the first channel, and extracting a noise figure in relation to the first channel by using the mean value of the pixel values of the whole projection area in relation to the first channel. Furth