A one-shot-projection method for measurement of specular surfaces

Abstract

Abstract:In this paper, a method is proposed to measure the shapes of specular surfaces with one-shot-projection of structured laser patterns. By intercepting the reflection of the reflected laser pattern twice with two diffusive planes, the closed form solution is achieved for each reflected ray. The points on the specular surface are reconstructed by computing the intersections of the incident rays and the reflected rays. The proposed method can measure both static and dynamic specular shapes due to its oneshot-projection, which is beyond the capability of most of state of art methods that need multiple projections. To our knowledge, the proposed method is the only method so far that could yield the closed form solutions for the dynamic and specular surfaces.

Removal of noise and radial lens distortion during calibration of computer vision systems

“…In most cases [11][12][13][14][15][16][17][18][19][20], the designed patterns keep the distances between adjacent markers the same for convenience. In this section, we propose a 3D pattern modeling method to eliminate the noise based on the distances between the center marker and the other markers.…”

“…This paper mainly deals with the noise of projector calibration and camera calibration in the structured light scanning system [11][12][13][14][15][16][17][18][19]. The structured light scanning methods [11][12][13][14][15][16][17][18][19] project some designed patterns onto the surface of the object to be measured. From the distorted pattern, the surface's profile could be calculated based on the system parameters calculated from a set of calibrated markers.…”

“…Consequently, the measurement accuracy is very poor. In [11], a SNF laser is used instead of the projector. The radial distortion is avoided and the contrast of the image is also increased because of the higher power of SNF laser compared to the Pico laser projector.…”

Technique for measuring the three-dimensional shapes of telescope mirrors

“…To improve the measurement accuracy, the pico laser projector was replaced with an silicon nitride film (SNF) laser, which is free from lens distortion and achieves better measurement accuracy. 24 However, the measurement accuracy is still not good enough because the noise significantly reduces the measurement accuracy. The used SNF laser does not strictly obey central projection from which some fundamental equations of the system are derived.…”

“…The used SNF laser does not strictly obey central projection from which some fundamental equations of the system are derived. Consequently, the reconstruction result of the system would be greatly distorted and the least deformation principle 24 is required to recalibrate the system, which is very time-consuming.…”