Flexible calibration of structured-light systems projecting point patterns

Ben-Hamadou, Achraf; Soussen, Charles; Daul, Christian; Blondel, Walter

doi:10.1016/j.cviu.2013.06.002

Cited by 34 publications

(25 citation statements)

References 33 publications

(57 reference statements)

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“…The fringe projection moves the camera position and the focal length to provide measurements of variable range via re-calibration. 17 This method detects black and white rectangles to perform the transformation P w to P c . 23 The spot projection re-calibrates the camera position and the focal length to perform measurements of variable range.…”

Section: Related Workmentioning

confidence: 99%

“…This procedure improves the measurements of variable range, which adjust the vision parameters via external re-calibration. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] The measurements of variable range via variable focal length are described in the section on 'Measurements of variable range via variable focal length'.…”

Section: Bezier Network Of a Laser Line And Variable Focal Lengthmentioning

confidence: 99%

“…30 The relative error is computed by the relative rms(%)5rms6100/-h. For the shoe-last bottom, the mean ish516?25 mm and the relative error is e50?618%. The confidence level is calculated via equation (17) for n5400 and a standard deviation s x 55?702. The result z a 52?16 indicates a confidence level over 95%.…”

Section: Measurements Of Variable Range Via Variable Focal Lengthmentioning

confidence: 99%

“…11,12,19 These limitations reduce the capability of the traditional measurements of variable range. [9][10][11][12][13][14][15][16][17][18][19] The proposed method performs measurements of variable range via variable focal length without recalibration during the vision task. This flexible measurement method is carried out via Bezier networks based on the line position and the focal length.…”

Section: Introductionmentioning

confidence: 99%

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Three-dimensional recovering based on variable focal length via Bezier networks

Muñoz-Rodríguez

2014

The Imaging Science Journal

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An automatic technique to perform measurements of variable range via variable focal length is presented. This technique provides measurements of variable range by means of a Bezier network based on a laser line projection. The variable range measurements are performed by adjusting the camera position and the focal length. These parameters are automatically computed during the vision task by means of the line position. Also, the initial calibration of vision parameters is carried out via image processing of the laser line. Thus, the proposed technique avoids external re-calibration, which is applied by the traditional methods of flexible measurements. This leads to an improvement of accuracy of the measurements of variable range via Bezier network. It is because the proposed method does not add errors of external re-calibration to the measurement process. This technique performs measurements of variable range via magnification of the surface depth, when it is not retrieved by the initial configuration. Thus, the system adapts the setup to the resolution of complex surface, which is being profiled. Furthermore, the adjustment does not interrupt the vision procedure because the change of vision parameters is calculated in a fraction of second. The contribution of this technique is elucidated by an evaluation based on the traditional measurements of variable range. Also, the time to achieve the surface measurements is examined.

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Section: Related Workmentioning

confidence: 99%

Section: Bezier Network Of a Laser Line And Variable Focal Lengthmentioning

confidence: 99%

Section: Measurements Of Variable Range Via Variable Focal Lengthmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Three-dimensional recovering based on variable focal length via Bezier networks

Muñoz-Rodríguez

2014

The Imaging Science Journal

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“…There have been several research works to address this classical problem. [10][11][12][13] The main difficulty in the calibration of the projector-camerabased SLS is how to precisely calibrate the projector device. As the projector cannot "see" the calibration target like the camera, existing camera calibration methods cannot be applied directly.…”

Section: Introductionmentioning

confidence: 99%

Method for calibration accuracy improvement of projector-camera-based structured light system

Song

2017

Opt. Eng

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, "Method for calibration accuracy improvement of projector-camera-based structured light system," Opt. Eng. 56(7), 074101 (2017), doi: 10.1117/1.OE.56.7.074101. Abstract. Calibration is a critical step for the projector-camera-based structured light system (SLS).Conventional SLS calibration means usually use the calibrated camera to calibrate the projector device, and the optimization of calibration parameters is applied to minimize the two-dimensional (2-D) reprojection errors. A three-dimensional (3-D)-based method is proposed for the optimization of SLS calibration parameters. The system is first calibrated with traditional calibration methods to obtain the primary calibration parameters. Then, a reference plane with some precisely printed markers is used for the optimization of primary calibration results. Three metric error criteria are introduced to evaluate the 3-D reconstruction accuracy of the reference plane. By treating all the system parameters as a global optimization problem and using the primary calibration parameters as initial values, a nonlinear multiobjective optimization problem can be established and solved. Compared with conventional calibration methods that adopt the 2-D reprojection errors for the camera and projector separately, a global optimal calibration result can be obtained by the proposed calibration procedure. Experimental results showed that, with the optimized calibration parameters, measurement accuracy and 3-D reconstruction quality of the system can be greatly improved.

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