CN107481207A - Method and system for geometric correction of video images - Google Patents

Abstract

The invention relates to a geometric correction method and a system of a video image, wherein the method comprises the following steps: the digital camera shoots an image projected by each projector independently; processing and matrix transformation calculation are carried out on the image, and a projection area of each projector after distortion on the projection screen is obtained; calculating an outer enclosure box of the whole projection wall; calculating the relative position of the projection area of each projector in the outer bounding box according to the outer bounding box, and obtaining the position coordinates of the relative position; and mapping the video image to be displayed to the relative position according to the position coordinate, and correctly splicing the projected video image. Before correction, data of geometric correction is written into a configuration file Geomparam.ini, and when video images are corrected, configuration information of each projector is read from the configuration file Geomparam.ini to perform geometric correction on the video images, so that projected video images can be well and correctly spliced.

Description

Method and system for geometric correction of video images

technical field

The invention relates to the technical field of video image correction, in particular to a method and system for geometric correction of video images.

Background technique

For playing video on a projection wall system that is spliced and displayed by multiple projectors, the shape of the video screen projected by each projector is not necessarily rectangular, and most of the screen sizes cannot be the same, so we need to adjust each projector The projected picture is geometrically corrected, and the picture is "distorted" back, so that the multiple pictures that are actually displayed can be seamlessly spliced into one logically as if it were projected by a large projector.

The current mechanical calibration is to equip each projector with a base with multiple degrees of freedom of adjustment, then fix the projector to this base, and adjust each degree of freedom manually (including position, base, etc. ), so that the projection direction of the projectors is perpendicular to the projection screen, and two projectors can be spliced and displayed correctly. However, even if each projector is equipped with such an accurate calibration instrument, this calibration work still requires skilled technicians to manually calibrate each projector, which is very cumbersome and time-consuming work, and when the number of projectors is large This work is especially difficult when you are older.

Contents of the invention

Based on this, it is necessary to provide a method and system for geometric correction of video images for the problem that skilled technicians are required to manually correct each projector.

A method for geometric correction of video images, comprising: a digital camera shoots images independently projected by each projector; processing and matrix transformation calculations are performed on the images to obtain a distorted projection area of each projector on a projection screen; calculation The outer bounding box of the entire projection wall; calculate the relative position of the projection area of each projector in the outer bounding box according to the outer bounding box, and obtain the position coordinates of the relative position; The display video images are mapped to the relative positions, and the projected video images are spliced correctly.

Preferably, the processing includes: acquisition of correction grids and acquisition of feature points; the calculation of matrix transformation includes: calculation of effective display area and calculation of mapping matrix.

Preferably, the digital camera shoots the image independently projected by each projector; before the step of processing the image and calculating the matrix transformation, it includes: calculating the texture to be displayed on the projection screen of each projector according to the configuration information. The ratio of the screen video image; according to the ratio, the video image to be displayed is segmented, and the divided sub-video image is generated into a texture with a size of 1024*1024.

Preferably, the effective projection area of each projector is a large polygon, and the polygon is a small quadrilateral pieced together by a plurality of small quadrilaterals, and the video image to be displayed is mapped to the relative position according to the position coordinates. The steps include: calculating the texture coordinates of the four vertices of each small quadrilateral according to the configuration information; sequentially mapping the 1024*1024 texture to the small quadrilateral according to the texture coordinates.

A geometric correction system of a video image, comprising: a video image processing module, an outer bounding box calculation module, a relative position calculation module and a mapping module; the video image processing module is used for digital cameras to take images projected separately by each projector ; The image is processed and matrix transformation calculation is performed to obtain the distorted projection area of each projector on the projection screen; the outer bounding box calculation module is used to calculate the outer bounding box of the entire projection wall; the relative position The calculation module is used to calculate the relative position of the projection area of each projector in the outer bounding box according to the outer bounding box, and obtain the position coordinates of the relative position; The position coordinates map the video image to be displayed to the relative position, and the projected video images are spliced correctly.

Preferably, the processing includes: acquisition of correction grids and acquisition of feature points; the calculation of matrix transformation includes: calculation of effective display area and calculation of mapping matrix.

Preferably, it also includes: a texture generation module; the texture generation module is used to calculate the ratio of the texture to be displayed on the projection screen of each projector to the entire large-screen video image according to the configuration information; according to the ratio to be displayed The video image is segmented, and the divided sub-video image is generated into a texture with a size of 1024*1024.

Preferably, the effective projection area of each projector is a large polygon, and the polygon is a small quadrilateral made up of a plurality of small quadrilaterals, and the mapping module is also used to calculate each small quadrilateral according to the configuration information. The texture coordinates of the four vertices; according to the texture coordinates, the 1024*1024 texture is mapped to the small quadrilateral in sequence.

The geometric correction method of the above-mentioned video image is to take the image projected by each projector independently by a digital camera; process the image and calculate the matrix transformation to obtain the distorted projection area of each projector on the projection screen, and calculate the entire projection area. The outer bounding box of the wall, calculate the relative position of the projection area of each projector in the outer bounding box according to the outer bounding box, and obtain the position coordinates of the relative position; according to the position coordinates, the video to be displayed The image is mapped to the relative position. Before the correction, write the geometric correction data into the configuration file GeomParam.ini. When correcting the video image, read the configuration information of each projector from the configuration file GeomParam.ini to perform geometric correction on the video image , it is very good to automatically splice the projected video images correctly.

Description of drawings

Fig. 1 is a schematic flowchart of a geometric correction method of a video image according to an embodiment;

FIG. 2 is a schematic structural diagram of a geometric correction system for video images according to an embodiment.

detailed description

The geometric correction method of video images in this solution is suitable for a projection wall system that is spliced and displayed by multiple projectors. When playing videos on the projection wall system, the field width, linearity, and geometric center position of each unit must be completely consistent, otherwise the large picture of the entire projection wall will have different distortions in different units. This method writes the data of geometric correction into the configuration file GeomParam. Perform geometric correction, and automatically splice the projected video images correctly.

Fig. 1 is the schematic flowchart of the geometric correction method of video image of an embodiment; As shown in Fig. 1, a kind of geometric correction method of video image comprises:

S11, the digital camera shoots the image independently projected by each projector; performs processing and matrix transformation calculation on the image, and obtains the distorted projection area of each projector on the projection screen;

Before performing correction, the corrected geometry data needs to be written into the configuration information.

As a preferred embodiment, the processing includes: acquiring the correction grid and acquiring the feature points; the matrix transformation calculation includes: calculating the effective display area and calculating the mapping matrix.

As a preferred embodiment, the digital camera shoots the image projected by each projector separately; before the step of processing the image and calculating the matrix transformation, it includes: calculating the texture to be displayed on the projection screen of each projector according to the configuration information The proportion of the entire large-screen video image; according to the proportion, the video image to be displayed is divided, and the divided sub-video image is generated into a texture with a size of 1024*1024.

S12, calculating the outer bounding box of the entire projection wall;

S13. Calculate the relative position of the projection area of each projector in the outer bounding box according to the outer bounding box, and obtain the position coordinates of the relative position;

S14. Map the video image to be displayed to the relative position according to the position coordinates, and splice the projected video images correctly.

As a preferred embodiment, the effective projection area of each projector is a large polygon, and the polygon is a small quadrilateral pieced together by a plurality of small quadrilaterals. According to the position coordinates, the video image to be displayed is mapped to the The step of relative position includes: calculating the texture coordinates of the four vertices of each small quadrilateral according to the configuration information; and sequentially mapping the texture with the size of 1024*1024 to the small quadrilateral according to the texture coordinates.

The geometric correction method of the above-mentioned video image is to take the image projected by each projector independently by a digital camera; process the image and calculate the matrix transformation to obtain the distorted projection area of each projector on the projection screen, and calculate the entire projection area. The outer bounding box of the wall, calculate the relative position of the projection area of each projector in the outer bounding box according to the outer bounding box, and obtain the position coordinates of the relative position; according to the position coordinates, the video to be displayed The image is mapped to the relative position. Before the correction, write the geometric correction data into the configuration file GeomParam.ini. When correcting the video image, read the configuration information of each projector from the configuration file GeomParam.ini to perform geometric correction on the video image , it is very good to automatically splice the projected video images correctly.

Fig. 2 is the schematic structural diagram of the geometric correction system of video image of an embodiment; As shown in Fig. 2, a kind of geometric correction system of video image comprises: video image processing module 11, outer bounding box calculation module 12, relatively Position calculation module 13 and mapping module 14; Described video image processing module 11, is used for digital camera to take the image that each projector projects separately; Described image is processed and matrix transformation calculation, obtains each projector in projection screen The projection area after upper distortion; the outer bounding box calculation module 12 is used to calculate the outer bounding box of the entire projection wall; the relative position calculation module 13 is used to calculate the projection of each projector according to the outer bounding box The relative position of the region in the outer bounding box, and obtain the position coordinates of the relative position; the mapping module 14 is used to map the video image to be displayed to the relative position according to the position coordinates, and the projected The video images are spliced correctly.

As a preferred embodiment, the processing includes: acquiring the correction grid and acquiring the feature points; the matrix transformation calculation includes: calculating the effective display area and calculating the mapping matrix.

As a preferred embodiment, it also includes: a texture generation module; the texture generation module is used to calculate the ratio of the texture to be displayed on the projection screen of each projector to the entire large-screen video image according to the configuration information; according to the Segment the video image to be displayed according to the ratio, and generate a texture with a size of 1024*1024 from the divided sub-video image.

As a preferred embodiment, the effective projection area of each projector is a large polygon, and the polygon is a small quadrilateral made up of multiple small quadrilaterals. The mapping module is also used to calculate each The texture coordinates of the four vertices of the small quadrilateral; map the texture of the size of 1024*1024 to the small quadrilateral sequentially according to the texture coordinates.

In the geometric correction system of the above-mentioned video image, the video image processing module captures the image projected by each projector independently through a digital camera; processes the image and performs matrix transformation calculation to obtain the distorted projection area of each projector on the projection screen , the outer bounding box calculation module calculates the outer bounding box of the entire projection wall, and the relative position calculation module calculates the relative position of the projection area of each projector in the outer bounding box according to the outer bounding box, and obtains the relative position position coordinates; the mapping module maps the video image to be displayed to the relative position according to the position coordinates. Before the correction, write the geometric correction data into the configuration file GeomParam.ini. When correcting the video image, read the configuration information of each projector from the configuration file GeomParam.ini to perform geometric correction on the video image , it is very good to automatically splice the projected video images correctly.

The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, should be considered as within the scope of this specification.

The above-mentioned embodiments only express several implementation modes of the present invention, and the descriptions thereof are relatively specific and detailed, but should not be construed as limiting the patent scope of the invention. It should be pointed out that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent for the present invention should be based on the appended claims.

Claims (8)

1. A geometric correction method of a video image, characterized in that, comprising: The digital camera shoots the image independently projected by each projector; the image is processed and matrix transformation calculation is performed to obtain the distorted projection area of each projector on the projection screen; Calculate the outer bounding box of the entire projection wall; Calculate the relative position of the projection area of each projector in the outer bounding box according to the outer bounding box, and obtain the position coordinates of the relative position; The video images to be displayed are mapped to the relative positions according to the position coordinates, and the projected video images are spliced correctly. 2. The geometric correction method of a video image according to claim 1, wherein said processing comprises: acquisition of a correction grid and acquisition of feature points; The matrix transformation calculation includes: the calculation of the effective display area and the calculation of the mapping matrix. 3. the geometric correction method of video image according to claim 1, is characterized in that, digital camera is taken the image that each projector projects separately; Before the step that described image is processed and matrix transformation calculation comprises: Calculate the ratio of the texture to be displayed on the projection screen of each projector to the entire large-screen video image according to the configuration information; The video image to be displayed is divided according to the ratio, and the divided sub-video image is generated into a texture with a size of 1024*1024. 4. the geometric correction method of video image according to claim 3, is characterized in that, the effective projection area of each projector is a large polygon, and described polygon is the small quadrilateral that is pieced together by a plurality of small quadrilaterals, The step of mapping the video image to be displayed to the relative position according to the position coordinates includes: Calculate the texture coordinates of the four vertices of each small quadrilateral according to the configuration information; Mapping the texture with a size of 1024*1024 to the small quadrilateral sequentially according to the texture coordinates. 5. A geometric correction system of a video image, comprising: a video image processing module, an outer bounding box calculation module, a relative position calculation module and a mapping module; The video image processing module is used for the digital camera to take images projected independently by each projector; to process the images and perform matrix transformation calculations to obtain the distorted projection areas of each projector on the projection screen; The outer bounding box calculation module is used to calculate the outer bounding box of the entire projection wall; The relative position calculation module is used to calculate the relative position of the projection area of each projector in the outer bounding box according to the outer bounding box, and obtain the position coordinates of the relative position; The mapping module is configured to map the video image to be displayed to the relative position according to the position coordinates, and the projected video images are spliced correctly. 6. The geometric correction system of video images according to claim 5, wherein said processing comprises: acquisition of a correction grid and acquisition of feature points; The matrix transformation calculation includes: the calculation of the effective display area and the calculation of the mapping matrix. 7. The geometric correction system of video images according to claim 5, further comprising: a texture generation module; The texture generation module is used to calculate the ratio of the texture to be displayed on the projection screen of each projector to the entire large-screen video image according to the configuration information; divide the video image to be displayed according to the ratio, and divide the divided sub- The video image generates a texture of 1024*1024 size. 8. the geometric correction system of video image according to claim 7, is characterized in that, the effective projection area of each projector is a large polygon, and described polygon is the small quadrilateral that is pieced together by a plurality of small quadrilaterals, The mapping module is further configured to calculate the texture coordinates of the four vertices of each small quadrilateral according to the configuration information; and sequentially map the texture of the size of 1024*1024 to the small quadrilateral according to the texture coordinates.