Calibration Method for Line-Structured Light Three-Dimensional Measurement Based on a Simple Target

Li, Xuexing; Zhang, Wenhui; Song, Guanglei

doi:10.3390/photonics9040218

Cited by 3 publications

(3 citation statements)

References 31 publications

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“…After the calculation process mentioned in Section 4.3, the intrinsic and extrinsic parameters of the binocular camera system have been calibrated simultaneously. The extrinsic parameters of the two cameras in the system can be expressed in more universal format by Equation ( 17): (17) The calibration results of the proposed method are shown in the bottom part of Table 14. It is worth noting that reference [8]'s binocular system calibration method (ACC method) can only calibrate extrinsic parameters with the prerequisite known monocular camera's intrinsic parameters.…”

Section: Real Binocular Camera System Calibration and 3d Reconstructi...mentioning

confidence: 99%

“…Calibration for structured-lightbased monocular camera measurement systems mainly include two progresses, which are intrinsic parameters calibration for the monocular camera and the extrinsic parameters calibration for the connecting structure of the monocular camera and light projection device. Calibration for structured-light-based monocular camera measurement has been studied by many scholars [17,18]. This paper focus more on the calibration of the second camera sensing system, which is the multi-camera-based stereo measurement system.…”

Section: Introductionmentioning

confidence: 99%

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A Stable, Efficient, and High-Precision Non-Coplanar Calibration Method: Applied for Multi-Camera-Based Stereo Vision Measurements

Zheng,

Duan,

et al. 2023

Sensors

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Traditional non-coplanar calibration methods, represented by Tsai’s method, are difficult to apply in multi-camera-based stereo vision measurements because of insufficient calibration accuracy, inconvenient operation, etc. Based on projective theory and matrix transformation theory, a novel mathematical model is established to characterize the transformation from targets’ 3D affine coordinates to cameras’ image coordinates. Then, novel non-coplanar calibration methods for both monocular and binocular camera systems are proposed in this paper. To further improve the stability and accuracy of calibration methods, a novel circular feature points extraction method based on region Otsu algorithm and radial section scanning method is proposed to precisely extract the circular feature points. Experiments verify that our novel calibration methods are easy to operate, and have better accuracy than several classical methods, including Tsai’s and Zhang’s methods. Intrinsic and extrinsic parameters of multi-camera-systems can be calibrated simultaneously by our methods. Our novel circular feature points extraction algorithm is stable, and with high precision can effectively improve calibration accuracy for coplanar and non-coplanar methods. Real stereo measurement experiments demonstrate that the proposed calibration method and feature extraction method have high accuracy and stability, and can further serve for complicated shape and deformation measurements, for instance, stereo-DIC measurements, etc.

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Section: Real Binocular Camera System Calibration and 3d Reconstructi...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A Stable, Efficient, and High-Precision Non-Coplanar Calibration Method: Applied for Multi-Camera-Based Stereo Vision Measurements

Zheng,

Duan,

et al. 2023

Sensors

View full text Add to dashboard Cite

show abstract

“…Other laser-plane calibration methods (Zhang and Zhang, 2017) include the single cylindrical target (Li et al, 2022), cross-ratio unchanged calibration method (Hu et al, 2010), three-point perspective principle (Han et al, 2009), vanishing point calculation, circular targets (Gong et al, 2017) and cylindrical object (Zhu et al, 2020). Chen et al, 2012b) proposed an optical plane calibration method based on the active vision technique to realize the automatic calibration of line-structured light sensors, and their method accomplished the calibration in two steps by controlling the sensor to perform some translational motions.…”

Section: Introductionmentioning

confidence: 99%

A unified calibration method of 3D laser profile measurement with different of laser-line lengths

Liu²,

Liu³

2023

RIA

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Purpose Existing calibration methods mainly focus on the camera laser-plane calibration of a single laser-line length, which is not convenient and cannot guarantee the consistency of the results when several three-dimensional (3D) scanners are involved. Thus, this study aims to provide a unified step for different laser-line length calibration requirements for laser profile measurement (LPM) systems. Design/methodology/approach 3D LPM is the process of converting physical objects into 3D digital models, wherein camera laser-plane calibration is critical for ensuring system precision. However, conventional calibration methods for 3D LPM typically use a calibration target to calibrate the system for a single laser-line length, which needs multiple calibration patterns and makes the procedure complicated. In this paper, a unified calibration method was proposed to automatically calibrate the camera laser-plane parameters for the LPM systems with different laser-line lengths. The authors designed an elaborate planar calibration target with different-sized rings that mounted on a motorized linear platform to calculate the laser-plane parameters of the LPM systems. Then, the camera coordinates of the control points are obtained using the intersection line between the laser line and the planar target. With a new proposed error correction model, the errors caused by hardware assembly can be corrected. To validate the proposed method, three LPM devices with different laser-line lengths are used to verify the proposed system. Experimental results show that the proposed method can calibrate the LPM systems with different laser-line lengths conveniently with standard steps. Findings The repeatability and accuracy of the proposed calibration prototypes were evaluated with high-precision workpieces. The experiments have shown that the proposed method is highly adaptive and can automatically calibrate the LPM system with different laser-line lengths with high accuracy. Research limitations/implications In the repeatability experiments, there were errors in the measured heights of the test workpieces, and this is because the laser emitter had the best working distance and laser-line length. Practical implications By using this proposed method and device, the calibration of the 3D scanning laser device can be done in an automatic way. Social implications The calibration efficiency of a laser camera device is increased. Originality/value The authors proposed a unified calibration method for LPM systems with different laser-line lengths that consist of a motorized linear joint and a calibration target with elaborately designed ring patterns; the authors realized the automatic parameter calibration.

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Adherent Peanut Image Segmentation Based on Multi-Modal Fusion

Wang,

Ye,

Zeng

et al. 2024

Sensors

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Aiming at the problem of the difficult segmentation of adherent images due to the not fully convex shape of peanut pods, their complex surface texture, and their diverse structures, a multimodal fusion algorithm is proposed to achieve a 2D segmentation of adherent peanut images with the assistance of 3D point clouds. Firstly, the point cloud of a running peanut is captured line by line using a line structured light imaging system, and its three-dimensional shape is obtained through splicing and combining it with a local surface-fitting algorithm to calculate a normal vector and curvature. Seed points are selected based on the principle of minimum curvature, and neighboring points are searched using the KD-Tree algorithm. The point cloud is filtered and segmented according to the normal angle and the curvature threshold until achieving the completion of the point cloud segmentation of the individual peanut, and then the two-dimensional contour of the individual peanut model is extracted by using the rolling method. The search template is established, multiscale feature matching is implemented on the adherent image to achieve the region localization, and finally, the segmentation region is optimized by an opening operation. The experimental results show that the algorithm improves the segmentation accuracy, and the segmentation accuracy reaches 96.8%.

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Calibration Method for Line-Structured Light Three-Dimensional Measurement Based on a Simple Target

Cited by 3 publications

References 31 publications

A Stable, Efficient, and High-Precision Non-Coplanar Calibration Method: Applied for Multi-Camera-Based Stereo Vision Measurements

A Stable, Efficient, and High-Precision Non-Coplanar Calibration Method: Applied for Multi-Camera-Based Stereo Vision Measurements

A unified calibration method of 3D laser profile measurement with different of laser-line lengths

Adherent Peanut Image Segmentation Based on Multi-Modal Fusion

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