Accurate projector calibration based on a new point-to-point mapping relationship between the camera and projector images

Abstract

The mapping relationship between the charge-coupled device (CCD) of a camera and the digital micro-mirror device (DMD) of a projector, together with the algorithm to estimate the parameters of the projector, determines the accuracy of projector calibration. In this paper, a new method is presented to achieve sub-pixel-level mapping between the camera and projector images. Instead of directly mapping the circle centers from the CCD to the DMD, which is pixel-precision-based, a set of pixels on the circle edge are extracted on the CCD and mapped onto the DMD. The locations of the circle centers are extracted on the DMD by the least-squares fitting technique, thus achieving sub-pixel precision. Compared with existing approaches based on the direct mapping of the circle centers on the camera image to the projector image, the proposed method is characterized by higher accuracy in mapping the points and thus the projector calibration. The experimental results are presented to show the effectiveness of the proposed method in the improvement of the accuracy of the projector calibration.

Out-of-Focus Projector Calibration Method with Distortion Correction on the Projection Plane in the Structured Light Three-Dimensional Measurement System

“…To improve the calibration accuracy of an out-of-focus projector, a unique one-to-one mapping between the pixels on the projector DMD and the pixels on the camera CCD should be virtually established in the phase domain using the phase shifting algorithm. The mapped projector images were generated, as proposed in [ 17 ], and the basic mapping principle can be described as follows. If the vertical structured light patterns, which are encoded with a combination of gray code and phase shifting, are projected onto the calibration board, and the camera captures the patterns images, the absolute phase can be retrieved for all of the camera pixels with Equations (5) and (6).…”

“…The corresponding relationship of the calibration points between the pixels on the projector Digital Micro-mirror Device (DMD) and the pixels on the camera Charge-Coupled Device (CCD) can be established. Then, the projector was calibrated using the same method as the camera, by using the corresponding points on the projector image and the calibration board [ 17 , 18 , 19 ]. This calibration approach does not depend on the accuracy of the camera calibration and can achieve higher accuracy, yet its process is complex.…”

Camera-Projector Calibration Methods with Compensation of Geometric Distortions in Fringe Projection Profilometry: A Comparative Study

“…The camera and projector pixel correspondences are obtained directly from the recovered phase, thus enabling the triangulation for estimating the 3D coordinates of object's surface. It is also worth noting that this approach is faster and more flexible in that accurate displacements are not required [11], [17], [18].…”

A Multi-Projector Calibration Method for Virtual Reality Simulators with Analytically Defined Screens

“…Many works on projector or multi-projector displays are based on planar surfaces [2][3][4][5][6][7][8], for which automated geometric correction and alignment is simplified through the use of planar homographies between the planar screen, the projector frame buffers, and the images of one or more cameras observing the screen. Many of these developments use chessboards-based planar references alone or with a combination of other planar surfaces to automatically measure 2D points (i.e., image points) and establish point correspondences [8][9][10][11][12][13][14].…”