Projector calibration method based on Scheimpflug principle

A calibration method, the technology of Sham's Law, applied in the field of computer vision, can solve the problems of blurred imaging, defocusing at both ends of the field of view, shallow depth of field, etc., to achieve the effect of improving the phase resolution accuracy, reducing the difficulty of calibration, and improving the accuracy of calibration

Pending Publication Date: 2021-07-23
中国科学院自动化研究所苏州研究院
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] 1. Using a projector with a common structure, there are problems such as shallow depth of field, defocusing at both ends of the field

Method used

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  • Projector calibration method based on Scheimpflug principle
  • Projector calibration method based on Scheimpflug principle
  • Projector calibration method based on Scheimpflug principle

Examples

Experimental program
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Effect test

Embodiment 1

[0324] According to a specific embodiment of the present invention, the method for calibrating a projector based on Sham's law of the present invention will be described in detail below.

[0325] The invention provides a method for calibrating a projector based on Sham's law, the method comprising the following steps:

[0326] 1. Collect the calibration pictures of the projector, the specific steps include:

[0327] (1) Within the depth of field of the camera, place the calibration plate in the projection area at a certain orientation, and project three different frequencies of horizontal and vertical sinusoidal fringe patterns, each frequency corresponds to 5 horizontal and vertical fringes. A fringe image, a total of 2*5*3 camera calibration images are obtained, and the calibration plate is not moved, and then a light without fringes is projected;

[0328] (2) Obtain a set of projector calibration pictures at one location, including 2*5*3+1 projector calibration pictures, a...

Embodiment 2

[0360] The image resolution projected by the DLP projector adopted in the present invention is 1280*720 pixels, the image resolution obtained by the camera is 2448*2048 pixels, and the Sham angles in the x direction and the y direction are respectively 4.637 ° and 0 °, which can be considered as There is no tilt in the y direction, and the corresponding periods of the projected three frequency fringes are 20, 22, and 24, respectively.

[0361] According to the method in Example 1, the image of the checkerboard calibration board used in the calibration process of the projector is collected, and the initial value of the internal parameter of the projector obtained by the calibration experiment is:

[0362]

[0363] The initial value of the internal parameters of the projector obtained after nonlinear optimization is:

[0364]

[0365] The distortion coefficient is: [0.33181 -0.05140 -0.00414 0.07085 0.94587];

[0366] The optimization result of Sham angle is: 3.22316°

[0...

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Abstract

The invention provides a projector calibration method based on the Scheimpflug principle, and belongs to the technical field of 3D structured light measurement. According to the invention, the calculation precision of the phase is improved by using a bidirectional multi-frequency multi-step phase shift method with higher precision for the Scheimpflug projector, an imaging model of the Scheimpflug projector is constructed and combined with the existing Zhang's analytical algorithm to calculate the initial values of internal and external parameters, and the internal parameters, the external parameters and the distortion coefficient of the projector are optimized by using the LM algorithm; the LM algorithm is further utilized to optimize the Scheimpflug angle, so that the calibration precision of the projector is improved.

Description

technical field [0001] The invention relates to the technical field of computer vision, in particular to a projector calibration method based on Sham's law. Background technique [0002] Structured light measurement technology refers to a measurement technology in which a special pattern is projected onto the surface of an object by a projector, the pattern modulated by the surface of the object is captured by the camera, and the three-dimensional information of the surface of the object to be measured is obtained through various recovery algorithms. At present, the projector has an important application in this technical field. The premise is that the internal and external parameters of the projector can be calibrated accurately, but the projector cannot image like a camera. This is where the difficulty of projector calibration lies. How to use the camera calibration algorithm De-calibration of projectors is still the focus of research in related fields. In addition, in or...

Claims

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Application Information

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IPC IPC(8): G06T7/80
CPCG06T7/80
Inventor 翟晓彤彭思龙汪雪林顾庆毅郭晓锋
Owner 中国科学院自动化研究所苏州研究院
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