Analysis of imaging for laser triangulation sensors under Scheimpflug rule

Mikš, Antonı́n; Novák, Jiří; Novák, Pavel

doi:10.1364/oe.21.018225

Cited by 38 publications

(20 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This would introduce the light interference when estimating the image spot’s position and finally impact the measuring accuracy. To improve this, the optical system needs to follow the Scheimpflug rule [23]. Then, Equation (2) should be satisfied:

tan θ_{1} = \frac{b}{a} \cdot tan θ_{2}

…”

Section: Measuring Principle Of Laser Triangulation Sensormentioning

confidence: 99%

A Laser-Based Measuring System for Online Quality Control of Car Engine Block

Wang

2016

Sensors

View full text Add to dashboard Cite

For online quality control of car engine production, pneumatic measurement instrument plays an unshakeable role in measuring diameters inside engine block because of its portability and high-accuracy. To the limitation of its measuring principle, however, the working space between the pneumatic device and measured surface is too small to require manual operation. This lowers the measuring efficiency and becomes an obstacle to perform automatic measurement. In this article, a high-speed, automatic measuring system is proposed to take the place of pneumatic devices by using a laser-based measuring unit. The measuring unit is considered as a set of several measuring modules, where each of them acts like a single bore gauge and is made of four laser triangulation sensors (LTSs), which are installed on different positions and in opposite directions. The spatial relationship among these LTSs was calibrated before measurements. Sampling points from measured shaft holes can be collected by the measuring unit. A unified mathematical model was established for both calibration and measurement. Based on the established model, the relative pose between the measuring unit and measured workpiece does not impact the measuring accuracy. This frees the measuring unit from accurate positioning or adjustment, and makes it possible to realize fast and automatic measurement. The proposed system and method were finally validated by experiments.

show abstract

tan θ_{1} = \frac{b}{a} \cdot tan θ_{2}

…”

Section: Measuring Principle Of Laser Triangulation Sensormentioning

confidence: 99%

A Laser-Based Measuring System for Online Quality Control of Car Engine Block

Wang

2016

Sensors

View full text Add to dashboard Cite

show abstract

“…The Scheimpflug camera, adopting the Scheimpflug condition by tilting the lens with respect to the sensor [1,2], can optimize the distribution of depth of field (DOF) without zooming the aperture, which has been widely used in the field of PIV [3][4][5], line structured light [6], and portable 3D laser scanner [7,8]. At the same time, it has also been introduced into the medical field, greatly facilitating cataract and other ophthalmic surgery [9,10].…”

Section: Introductionmentioning

confidence: 99%

“…At the same time, it has also been introduced into the medical field, greatly facilitating cataract and other ophthalmic surgery [9,10]. So far, more and more scholars have also devoted themselves to the related research [6,7,[11][12][13][14][15][16][17][18].…”

Section: Introductionmentioning

confidence: 99%

“…The principle is applicable to both thin prism and thick prism models, which only needs to be modified accordingly [1,2]. As for the case of a real optical system, it is likely to find that for different object points, the optical system have different fnumbers and different aberrations; thus, the image generated by the real optical system will not be completely sharp [7]. Yet, this influence usually can be ignored in the Scheimpflug camera research.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Review of Calibration Methods for Scheimpflug Camera

et al. 2018

View full text Add to dashboard Cite

The Scheimpflug camera offers a wide range of applications in the field of typical close-range photogrammetry, particle image velocity, and digital image correlation due to the fact that the depth-of-view of Scheimpflug camera can be greatly extended according to the Scheimpflug condition. Yet, the conventional calibration methods are not applicable in this case because the assumptions used by classical calibration methodologies are not valid anymore for cameras undergoing Scheimpflug condition. Therefore, various methods have been investigated to solve the problem over the last few years. However, no comprehensive review exists that provides an insight into recent calibration methods of Scheimpflug cameras. This paper presents a survey of recent calibration methods of Scheimpflug cameras with perspective lens, including the general nonparametric imaging model, and analyzes in detail the advantages and drawbacks of the mainstream calibration models with respect to each other. Real data experiments including calibrations, reconstructions, and measurements are performed to assess the performance of the models. The results reveal that the accuracies of the RMM, PLVM, PCIM, and GNIM are basically equal, while the accuracy of GNIM is slightly lower compared with the other three parametric models. Moreover, the experimental results reveal that the parameters of the tangential distortion are likely coupled with the tilt angle of the sensor in Scheimpflug calibration models. The work of this paper lays the foundation of further research of Scheimpflug cameras.

show abstract

“…The measurement accuracy of the LTDP is affected by the speckle, the color of the measured object, the surface texture, the ambient light, the variation in the laser beam intensity, the distortion of the receiver lens, and the dithering of the source laser beam [2][3][4][5]. Shen et al [6] introduced a digital correlation method for suppressing the speckle noise.…”

Section: Introductionmentioning

confidence: 99%

Development of a Laser Triangulation Displacement Probe with Laser Beam Pointing Control

Yang¹,

Tao²,

Zhang³

et al. 2017

Preprint

View full text Add to dashboard Cite

Directional dithering of a laser beam potentially limits the detection accuracy of a laser triangulation displacement probe. A theoretical analysis indicates that the measurement accuracy will linearly decrease as the laser dithering angle increases. To suppress laser dithering, a laser triangulation displacement probe with laser beam pointing control, which consists of a collimated red laser, a laser beam pointing control setup, a receiver lens, and a charge-coupled device, is proposed in this paper. The laser beam pointing control setup is inserted into the source laser beam and the measured object and can separate the source laser beam into two symmetrical laser beams. Hence, at the angle at which the source laser beam dithers, the positional averages of the two laser spots are equal and opposite. Moreover, a laser dithering compensation algorithm is used to maintain a stable average of the positions of the two spots on the imaging side. Experimental results indicate that with laser beam pointing control, the standard variance of the fitting error decreases from 0.3531 to 0.0100, the repeatability accuracy can be decreased from ±7 mm to ±5 µm, and the nonlinear error can be reduced from ±6 %FS to ±0.16 %FS.

show abstract

Analysis of imaging for laser triangulation sensors under Scheimpflug rule

Cited by 38 publications

References 13 publications

A Laser-Based Measuring System for Online Quality Control of Car Engine Block

A Laser-Based Measuring System for Online Quality Control of Car Engine Block

Review of Calibration Methods for Scheimpflug Camera

Development of a Laser Triangulation Displacement Probe with Laser Beam Pointing Control

Contact Info

Product

Resources

About