Abstract:Abstract. Visual inspection for a highly reflective surface is commonly faced with a serious limitation, which is that useful information on geometric construction and textural defects is covered by a parasitic image due to specular highlights. In order to solve the problem, we propose an effective method for removing the parasitic image. Specifically, a digital micromirror device (DMD) camera for programmable imaging is first described. The strength of the optical system is to process scene ray before image f… Show more
“…The distortion on x-axis is obviously bigger than the distortion on y-axis. And the linear growth is consistent with previous theoretical derivation in Ref 30 . Figure 1 DMD imaging system.…”
Section: Introductionsupporting
confidence: 92%
“…We constructed an imaging system called DMD camera that was applied on 3D shape measurement and noise removal 30 , 31 . The difference between DMD camera and single-pixel camera is mainly that the single photon detector is replaced by array charge coupled device (CCD).…”
Three-Dimensional shape measurement has been confronted with the ambiguity on the steep surface. To address the problem, compressed sensing theory is employed to reconstruct phase shifting images in DMD camera. Specially, every CCD pixel in the region of interest is aligned to N × N DMD mirrors to construct DMD camera. The one-dimensional measurement matrices are chosen to collect the measured values on CCD pixel according to the directional judgement of original gradient image. Due to the enhancement of the spatial sampling frequency and the noise robustness, the reconstructed sinusoidal stripe images are utilized to obtain the three-dimensional model of the steep surface accurately. We measure the planes with various slopes to discuss the measurement capability. The comparative experiments show that our proposed method can correct the deformed phase and repair the defect on the steep surface.
“…The distortion on x-axis is obviously bigger than the distortion on y-axis. And the linear growth is consistent with previous theoretical derivation in Ref 30 . Figure 1 DMD imaging system.…”
Section: Introductionsupporting
confidence: 92%
“…We constructed an imaging system called DMD camera that was applied on 3D shape measurement and noise removal 30 , 31 . The difference between DMD camera and single-pixel camera is mainly that the single photon detector is replaced by array charge coupled device (CCD).…”
Three-Dimensional shape measurement has been confronted with the ambiguity on the steep surface. To address the problem, compressed sensing theory is employed to reconstruct phase shifting images in DMD camera. Specially, every CCD pixel in the region of interest is aligned to N × N DMD mirrors to construct DMD camera. The one-dimensional measurement matrices are chosen to collect the measured values on CCD pixel according to the directional judgement of original gradient image. Due to the enhancement of the spatial sampling frequency and the noise robustness, the reconstructed sinusoidal stripe images are utilized to obtain the three-dimensional model of the steep surface accurately. We measure the planes with various slopes to discuss the measurement capability. The comparative experiments show that our proposed method can correct the deformed phase and repair the defect on the steep surface.
“…In the linear space invariant imaging system composed of DMD and CCD [ 31 ], a point on the object plane is mapped not only as a corresponding points on the image plane, but also be spread into an area. Therefore, the single point on the image plane is actually the superposition of many corresponding points on the object plane.…”
High-speed photography is an important tool for studying rapid physical phenomena. However, low-frame-rate CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) camera cannot effectively capture the rapid phenomena with high-speed and high-resolution. In this paper, we incorporate the hardware restrictions of existing image sensors, design the sampling functions, and implement a hardware prototype with a digital micromirror device (DMD) camera in which spatial and temporal information can be flexibly modulated. Combined with the optical model of DMD camera, we theoretically analyze the per-pixel coded exposure and propose a three-element median quicksort method to increase the temporal resolution of the imaging system. Theoretically, this approach can rapidly increase the temporal resolution several, or even hundreds, of times without increasing bandwidth requirements of the camera. We demonstrate the effectiveness of our method via extensive examples and achieve 100 fps (frames per second) gain in temporal resolution by using a 25 fps camera.
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