Photogrammetric scale-bar measurement method based on microscopic image aiming

Gan, Xiaochuan; He, Ming-Ming; Li, Lianfu; Ye, Xiao-you; Li, Jian-shuang

doi:10.1117/12.974264

Cited by 3 publications

(3 citation statements)

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“…The length between the two RRTs is measured or calibrated by instruments with high (several micrometer) accuracy. One of the measurement instruments is composed by an interferometer, a microscope and a granite rail [ 25 , 26 ]. Generally, a scale bar performs in photogrammetry as a metric for true scale, especially in multi-image offline systems.…”

Section: Methodsmentioning

confidence: 99%

Simultaneous All-Parameters Calibration and Assessment of a Stereo Camera Pair Using a Scale Bar

Sun

Lü

Dong

et al. 2018

Sensors

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Highly accurate and easy-to-operate calibration (to determine the interior and distortion parameters) and orientation (to determine the exterior parameters) methods for cameras in large volume is a very important topic for expanding the application scope of 3D vision and photogrammetry techniques. This paper proposes a method for simultaneously calibrating, orienting and assessing multi-camera 3D measurement systems in large measurement volume scenarios. The primary idea is building 3D point and length arrays by moving a scale bar in the measurement volume and then conducting a self-calibrating bundle adjustment that involves all the image points and lengths of both cameras. Relative exterior parameters between the camera pair are estimated by the five point relative orientation method. The interior, distortion parameters of each camera and the relative exterior parameters are optimized through bundle adjustment of the network geometry that is strengthened through applying the distance constraints. This method provides both internal precision and external accuracy assessment of the calibration performance. Simulations and real data experiments are designed and conducted to validate the effectivity of the method and analyze its performance under different network geometries. The RMSE of length measurement is less than 0.25 mm and the relative precision is higher than 1/25,000 for a two camera system calibrated by the proposed method in a volume of 12 m × 8 m × 4 m. Compared with the state-of-the-art point array self-calibrating bundle adjustment method, the proposed method is easier to operate and can significantly reduce systematic errors caused by wrong scaling.

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Section: Methodsmentioning

confidence: 99%

Simultaneous All-Parameters Calibration and Assessment of a Stereo Camera Pair Using a Scale Bar

Sun

Lü

Dong

et al. 2018

Sensors

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“…A dualfrequency laser interferometer with high-precision length measurement performance provided the standard length for this test, and the uncertainty of the measurement length was 0.1 µm + 0.1 µm m −1 [22]. The specific test process involved ).…”

Section: Standard Length Measurement Testmentioning

confidence: 99%

“…The specific test process involved ). In addition, the dualfrequency laser interferometer records the standard lengths L 1 and L 2 , which are used for comparison with the lengths measured by the two RRTs to obtain their external coincidence accuracies [22].…”

Section: Standard Length Measurement Testmentioning

confidence: 99%

Retro-reflective target with high accuracy for industrial photogrammetry

Huang¹,

Huang²,

Zhang³

et al. 2022

Meas. Sci. Technol.

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Retro-reflective targets (RRTs) are important for obtaining the coordinates of the surface points of objects measured using industrial photogrammetry systems. Targeting the low measurement accuracy caused by the poor roundness of the conventional RRT, a novel RRT was designed in this study by covering a die-cut slice with round holes and high roundness on a glass bead reflective film. The roundness of this novel RRT was on average 0.03 mm higher than that of the conventional RRT. The accuracy of the novel RRT was evaluated in terms of both internal and external coincidence accuracies. The measurement repeatability accuracy of the novel RRT was improved by 25.0% compared with that of the conventional RRT. The thinner the die-cut slice thickness, the higher the repeatability in a certain range. Similarly, the plane fitting, flatness measurement, and standard length measurement accuracies were improved by 30.7%, 34.1%, and 28.1%, respectively.

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Handy Microscopic Close-Range Videogrammetry

Esmaeili

Ebadi

2017

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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The modeling of small-scale objects is used in different applications such as medicine, industry, and cultural heritage. The capability of modeling small-scale objects using imaging with the help of hand USB digital microscopes and use of videogrammetry techniques has been implemented and evaluated in this paper. Use of this equipment and convergent imaging of the environment for modeling, provides an appropriate set of images for generation of three-dimensional models. The results of the measurements made with the help of a microscope micrometer calibration ruler have demonstrated that self-calibration of a hand camera-microscope set can help obtain a three-dimensional detail extraction precision of about 0.1 millimeters on small-scale environments.

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Photogrammetric scale-bar measurement method based on microscopic image aiming

Cited by 3 publications

References 0 publications

Simultaneous All-Parameters Calibration and Assessment of a Stereo Camera Pair Using a Scale Bar

Simultaneous All-Parameters Calibration and Assessment of a Stereo Camera Pair Using a Scale Bar

Retro-reflective target with high accuracy for industrial photogrammetry

Handy Microscopic Close-Range Videogrammetry

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