A calibration method of fringe projection system based on mirror
A fringe projection and system calibration technology, applied in the field of optical measurement, can solve problems such as errors and uneven thickness of printing paper, and achieve the effect of avoiding loss and high-precision panoramic three-dimensional measurement
Active Publication Date: 2021-05-07
NANJING UNIV OF SCI & TECH
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Problems solved by technology
On the one hand, due to the uneven thickness of the printing paper with the speckle pattern, it will inevitably introduce errors in the calibration process of the mirror
On the other hand, for measurement systems with mirrors, it leads to a limited 3D measurement volume of the system since the paper is fixed on the mirrors
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[0065] For verifying the effectiveness of the method described in the present invention, use a camera (model acA2440-75um, Basler), a projector (model LightCrafter 4500PRO, TI), two mirrors of front surface reflection (size is 30cm * 30cm ) and a computer to build a set of three-dimensional measuring device based on the calibration method of the fringe projection system based on the mirror. The shooting speed of this set of devices is 25 frames per second when performing three-dimensional measurement of objects. Using the description in step 1, in the traditional measurement system based on fringe projection profilometry (FPP) composed of a camera and a projector, two mirrors are placed behind the measured object, and the angle between the two mirrors is about 120°. Through the reflection of the mirror, the camera can image the measured object from the front and two different viewing angles (left mirror and right mirror), so as to obtain 360° two-dimensional information of th...
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The invention discloses a method for calibrating a fringe projection system based on mirrors. Firstly, two mirrors are placed behind the object to be measured. Through the reflection of the mirrors, the camera can measure the object to be measured from the front and other two angles of view. Imaging, so as to obtain the 360 ° two-dimensional information of the measured object; the projector projects three sets of phase-shifted grating patterns, the frequency is 1, 8 and 64; the camera collects the grating pattern to obtain the frequency of 64 Absolute phase map; use the calibration parameters between the projector and the camera to convert the absolute phase map into the three-dimensional information of the measured object; then realize the calibration of the mirror by capturing a set of 3D feature point pairs, so that the three-dimensional information from different perspectives can be converted to a unified world coordinate system. The present invention does not need to artificially fix characteristic patterns on the reflector, and only needs a camera to capture a set of 3D feature point pairs to directly realize the reflector calibration, avoiding the loss of measurement accuracy, and realizing high-precision panoramic three-dimensional measurement.
Description
technical field [0001] The invention belongs to the technical field of optical measurement, and in particular relates to a method for calibrating a fringe projection system based on a mirror. Background technique [0002] In recent decades, rapid 3D shape measurement technology has been widely used in various fields, such as intelligent monitoring, industrial quality control and 3D face recognition. Among the many 3D shape measurement methods, fringe projection profilometry based on the principle of structured light and triangulation is one of the most practical techniques due to its advantages of non-contact, full-field, high precision and high efficiency. It enables non-contact and high-precision 3D imaging of objects with complex curved surfaces, and allows high-speed measurement of dynamic scenes, such as fast-moving objects, fast-rotating or vibrating non-rigid body motions. However, in the traditional measurement system based on fringe projection profilometry (FPP) co...
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IPC IPC(8): G01B11/25
CPCG01B11/2504G01B11/2513G01B11/2527
Inventor 左超尹维陈钱冯世杰孙佳嵩陶天阳胡岩张良钱佳铭
Owner NANJING UNIV OF SCI & TECH