CN-115953481-B - Projection equipment and projection equipment parameter calibration method

CN115953481BCN 115953481 BCN115953481 BCN 115953481BCN-115953481-B

Abstract

Some embodiments of the application provide a projection device and a projection device parameter calibration method. After a user inputs a parameter calibration instruction to the projection device, the projection device projects the first image card to a calibration area, and acquires a first image shot by the first image card, wherein the calibration area comprises characteristic points and coding points. The projection device identifies a code point in the first image and obtains a first matching relationship between the image coordinate system and the world coordinate system based on the code point. The projection device identifies feature points in the first image and obtains a second matching relationship between the image coordinate system and the opto-mechanical coordinate system based on the feature points. The projection device calibrates the projection device parameters based on the first matching relationship and the second matching relationship. The projection equipment can calibrate the actual parameters by itself instead of adopting the theoretical parameters, thereby improving the accuracy of image correction and improving the use experience of users.

Inventors

WANG HAO
YANG LIJUAN
YUE GUOHUA
LI JIALIN

Assignees

海信集团控股股份有限公司

Dates

Publication Date: 20260508
Application Date: 20221229

Claims (7)

1.A projection device, comprising: A light emitting assembly configured to project projected content onto a projection surface; A camera configured to capture an image in a projection plane; A controller configured to: The method comprises the steps of responding to parameter calibration instructions input by a user, controlling the light emitting assembly to project a first image card to a calibration area, and obtaining a first image shot by a camera on the first image card, wherein the projection surface comprises the calibration area, the calibration area comprises characteristic points and coding points, and the coding points comprise a circle center area and a circular ring area; Performing binarization processing on the first image to obtain a binarized image; Performing closed contour recognition on the binarized image to obtain a plurality of closed contours; acquiring roundness of the plurality of closed contours, and determining the closed contour with the roundness being greater than or equal to a preset roundness threshold as a first closed contour; Acquiring the number of contour points of the first closed contour, and determining the first closed contour with the number of contour points larger than a preset number threshold as a second closed contour; Fitting the second closed contour to obtain a fitted contour; Calculating a first area of the second closed contour and a second area of the fitted contour, and calculating a ratio of the second area to the first area; Obtaining a target fitting contour corresponding to a ratio meeting a preset ratio condition; acquiring a first code of the code point, wherein the code point corresponds to a unique first code; affine transformation is carried out on the target fitting contour to obtain a target contour; acquiring a second code corresponding to the target contour; if the target first code and the second code are the same, determining the target outline as a circle center area of a code point corresponding to the target first code; acquiring a first matching relation between an image coordinate system and a world coordinate system based on the coding points; identifying feature points in the first image; acquiring a second matching relation between an image coordinate system and an optical machine coordinate system based on the characteristic points; And calibrating the projection equipment parameters based on the first matching relation and the second matching relation.
2. The projection device of claim 1, wherein the controller performs a closed contour recognition process on the binarized image, and is further configured to: carrying out external contour recognition on the binarized image to obtain a first external contour; Acquiring the contour area of the first external contour and the image area of the first image; if the ratio of the contour area to the image area is smaller than or equal to a preset contour ratio, determining the first external contour as a closed contour; If the ratio of the contour area to the image area is larger than the contour ratio, deleting the first external contour in the binarized image, and carrying out external contour recognition on the binarized image to obtain a second external contour, and determining the second external contour as a closed contour.
3. The projection device of claim 1, wherein the controller performs acquiring a second encoding corresponding to the target contour, further configured to: Acquiring the coding quantity of a first code, and equally dividing the target contour into contour branches of the coding quantity; dividing the profile branch into a plurality of profile intervals; Acquiring a first radius of the target profile, and acquiring a radius threshold value based on the first radius; taking the circle center of the target contour as the circle center and the second radius as the radius, and making a circular contour; Acquiring gray values of pixel points corresponding to the circular outline within the angles of the outline intervals; Determining the color of the contour interval, wherein the contour interval is determined to be a first color if the gray value corresponding to the second radius exceeding the preset number is larger than the preset gray value; Traversing the colors of the contour intervals in the contour branches to determine the color with the largest number as the color of the contour branches; determining a numerical value corresponding to the contour branch based on the color of the contour branch; And acquiring a second code corresponding to the target contour based on the value corresponding to the contour branch.
4. The projection device of claim 1, wherein the controller performs a first matching relationship between the acquisition image coordinate system and the world coordinate system based on the encoding points, and is further configured to: Acquiring first image coordinates of a circle center region of the coding point in the first image; Acquiring a first world coordinate of the coding point based on the calibration area; and calculating a first homography matrix based on the first image coordinate and the first world coordinate, and determining the first homography matrix as a first matching relation between an image coordinate system and a world coordinate system.
5. The projection device of claim 1, wherein the feature points comprise a center region, and wherein the controller is configured to identify feature points in the first image by: Acquiring second world coordinates of the feature points based on the calibration area; Identifying a circular profile of the number of closed profiles; Determining a circular outline outside the circle center area of the coding point as a first characteristic point; Acquiring image coordinates of the first feature points, and converting the image coordinates into world coordinates based on the first matching relationship; and if the second world coordinates of the targets exist and the world coordinates of the first feature points are the same, determining the first feature points as the second feature points.
6. The projection device of claim 5, wherein the controller performs a second matching relationship between the image coordinate system and the opto-mechanical coordinate system based on the feature points, and is further configured to: Selecting a plurality of pixel points in the closed contour of the second characteristic point; the light emitting component is controlled to project the grating image card to a calibration area, and a grating image shot by the camera on the grating image card is obtained; If the absolute phases of the pixel points meet the preset absolute phase condition, determining the second characteristic point as a target characteristic point; Acquiring a plurality of adjacent pixel points of the image coordinates of the target feature points; Performing interpolation processing on the absolute phases of the plurality of pixel points to obtain the absolute phases of the target feature points; acquiring the optical-mechanical coordinates of the target feature points based on the absolute phases of the target feature points; and calculating a second homography matrix based on the optical-mechanical coordinates and the image coordinates of the target feature points, and determining the second homography matrix as a second matching relationship between the image coordinate system and the optical-mechanical coordinate system.
7. The projection equipment parameter calibration method is characterized by being applied to projection equipment, wherein the projection equipment comprises a light emitting component, a camera and a controller, and the projection equipment parameter calibration method comprises the following steps: The method comprises the steps of responding to parameter calibration instructions input by a user, controlling the light emitting assembly to project a first image card to a calibration area, and obtaining a first image shot by a camera on the first image card, wherein the projection surface comprises the calibration area, the calibration area comprises characteristic points and coding points, and the coding points comprise a circle center area and a circular ring area; Performing binarization processing on the first image to obtain a binarized image; Performing closed contour recognition on the binarized image to obtain a plurality of closed contours; acquiring roundness of the plurality of closed contours, and determining the closed contour with the roundness being greater than or equal to a preset roundness threshold as a first closed contour; Acquiring the number of contour points of the first closed contour, and determining the first closed contour with the number of contour points larger than a preset number threshold as a second closed contour; Fitting the second closed contour to obtain a fitted contour; Calculating a first area of the second closed contour and a second area of the fitted contour, and calculating a ratio of the second area to the first area; Obtaining a target fitting contour corresponding to a ratio meeting a preset ratio condition; acquiring a first code of the code point, wherein the code point corresponds to a unique first code; affine transformation is carried out on the target fitting contour to obtain a target contour; acquiring a second code corresponding to the target contour; if the target first code and the second code are the same, determining the target outline as a circle center area of a code point corresponding to the target first code; acquiring a first matching relation between an image coordinate system and a world coordinate system based on the coding points; identifying feature points in the first image; acquiring a second matching relation between an image coordinate system and an optical machine coordinate system based on the characteristic points; And calibrating the projection equipment parameters based on the first matching relation and the second matching relation.

Description

Projection equipment and projection equipment parameter calibration method Technical Field The present application relates to the field of projection devices, and in particular, to a projection device and a parameter calibration method for the projection device. Background A projection device is a display device that can project images or video onto a screen. The projection device can project laser rays with specific colors to a screen through the refraction action of the optical lens assembly to form a specific image. When the projection device is used, if the position of the projection device is deviated or the projection device is not perpendicular to the projection surface, the deviation of the projection angle and the projection distance can be caused, so that the projection device cannot completely project an image to a preset projection area, the situation that the projection picture is deformed occurs, and the experience of a user is poor. Therefore, the display position and the shape of the projection image can be corrected by the image correction function of the projection device so as to avoid the situation that the projection picture is deformed. When the image correction is performed, the projection device corrects the projection image according to internal parameters including parameters such as an optical engine internal parameter, a camera external parameter and the like. However, when the theoretical parameters marked when the projection equipment leaves the factory are used, due to certain errors in the actual production and assembly process, the actual parameters and the theoretical parameters of the projection equipment are inconsistent, so that the accuracy of the projection equipment in image correction is poor, and the use experience of a user is seriously affected. Disclosure of Invention The application provides projection equipment and a projection equipment parameter calibration method, which are used for solving the problem that the use experience of a user is affected due to inconsistent actual parameters and theoretical parameters of the projection equipment. In a first aspect, some embodiments of the present application provide a projection device including a light extraction assembly, a camera, and a controller. The light emitting assembly is configured to project projection content onto a projection surface, the camera is configured to shoot an image in the projection surface, and the controller is configured to execute the following steps: the method comprises the steps of responding to parameter calibration instructions input by a user, controlling the light emitting assembly to project a first image card to a calibration area, and obtaining a first image shot by a camera on the first image card, wherein the projection surface comprises the calibration area, and the calibration area comprises characteristic points and coding points; identifying a code point in the first image; acquiring a first matching relation between an image coordinate system and a world coordinate system based on the coding points; identifying feature points in the first image; acquiring a second matching relation between an image coordinate system and an optical machine coordinate system based on the characteristic points; And calibrating the projection equipment parameters based on the first matching relation and the second matching relation. In a second aspect, some embodiments of the present application provide a method for calibrating parameters of a projection device, which is applied to the projection device, where the projection device includes a light emitting component, a camera, and a controller, and the method for calibrating parameters of the projection device includes: the method comprises the steps of responding to parameter calibration instructions input by a user, controlling the light emitting assembly to project a first image card to a calibration area, and obtaining a first image shot by a camera on the first image card, wherein the projection surface comprises the calibration area, and the calibration area comprises characteristic points and coding points; identifying a code point in the first image; acquiring a first matching relation between an image coordinate system and a world coordinate system based on the coding points; identifying feature points in the first image; acquiring a second matching relation between an image coordinate system and an optical machine coordinate system based on the characteristic points; And calibrating the projection equipment parameters based on the first matching relation and the second matching relation. According to the technical scheme, the projection equipment and the projection equipment parameter calibration method provided by some embodiments of the application are provided. After a user inputs a parameter calibration instruction to the projection device, the projection device projects the first image card to a calibration area, and acquir