Article
Computer Science, Artificial Intelligence
Amir HajiRassouliha, Samuel P. Richardson, Andrew J. Taberner, Martyn P. Nash, Poul M. F. Nielsen
Summary: This study quantifies the effect of changing camera settings on image noise level and subpixel displacement measurement accuracy through experimental design. The results show that camera parameters directly influence image noise level, but the accuracy of algorithms in measuring displacements is not proportional to the image noise level. This provides information on the quantitative relationship between camera settings and registration error in a camera-based measurement system.
MACHINE VISION AND APPLICATIONS
(2021)
Article
Engineering, Multidisciplinary
Zhenning Liang, Jinxiu Zhang, Longhui Qiu, Guangyi Lin, Fengfu Yin
Summary: The digital image correlation technique with non-fixed camera is developed for deformation measurement in the field, providing a more flexible and convenient method to measure deformation of high altitude facilities. Multiple images and feature templates are used for correction to ensure accuracy.
Article
Multidisciplinary Sciences
Wei-wei Sheng
Summary: This paper proposes a precise measurement method and corresponding calibration procedure for a line structure light vision sensor with a large measurement range. By utilizing a linear translation stage and planar target, the relationship between the center point of the laser stripe and the perpendicular/horizontal distance is obtained. The proposed method eliminates the need for distortion compensation and significantly improves measurement precision.
SCIENTIFIC REPORTS
(2023)
Article
Computer Science, Artificial Intelligence
Gerardo Paolillo, Tommaso Astarita
Summary: Camera calibration is a challenging task in studying fluid flows around complex transparent geometries. This research presents a camera model that accurately represents the refraction of light rays and offers a more efficient calibration method. The study discusses estimation issues and proposes feasible approaches, analyzes the effects of image noise and camera quantity, and demonstrates the effectiveness of the model through an application in 3D optical velocimetry measurements.
IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE
(2022)
Article
Computer Science, Artificial Intelligence
Sarah Miller, Chen Zhang, Keigo Hirakawa
Summary: The study introduces a denoising technique for low-photon imaging noise based on statistical compositional data analysis and Poisson distribution, which effectively preserves image contrast details. This technique exhibits wavelet-like properties in the difference-log-contrast and is robust to illumination variations.
IEEE TRANSACTIONS ON IMAGE PROCESSING
(2021)
Article
Optics
Jixiao Liu, Jupu Yang, Jingchen Li, Jialin Du, Siyang Yu, Fanxing Li, Jian Wang, Xi Zhang, Si Sun, Wei Yan
Summary: In this paper, a calibration method for high-precision zoom lenses of optical measurement machines based on Fully Connected Neural Network (FNN) is proposed. It achieves continuous calibration at any zoom setting by calibrating typical zooms, with better overall calibration precision and meeting the application requirements of high-precision optical measurement machines.
Article
Engineering, Multidisciplinary
Dashan Zhang, Wenhui Hou, Jie Guo, Xiaolong Zhang
Summary: This study proposes an improved two-step image registration algorithm to enhance algorithm efficiency by improving the accuracy of initial estimation and effectively reducing the dimension of the searching area. Experimental results demonstrate that the modified algorithm achieves the same subpixel accuracy as the original algorithm for large upsampling factors, while significantly reducing computational expense.
Article
Engineering, Multidisciplinary
Dashan Zhang, Wenhui Hou, Jie Guo, Xiaolong Zhang
Summary: An improved two-step image registration algorithm is proposed in this study to enhance the accuracy of initial estimation and effectively reduce the searching area dimension, achieving accurate estimation for large upsampling factors. Results show that the algorithm significantly reduces computational expense while decreasing the required time for high precision target tracking tasks.
Article
Engineering, Electrical & Electronic
Te-Mei Wang, Zen-Chung Shih
Summary: A novel method is proposed to measure and analyze depth resolution in near range, using different types of targets and specific steps to optimize the depth resolution of depth cameras.
IEEE SENSORS JOURNAL
(2021)
Article
Optics
Ying Kou, Longfei Zhang, Siyuan Liu, Qingchang Tan, Jiaying Lin, Ning Ding, Yueqian Hou, Kai Kan
Summary: This paper presents a method to obtain the conic invariant of the tested aperture diameter using ellipse geometric fitting, and establishes the transformation relationship between the world coordinate system and the camera coordinate system. By projecting the sub-pixel coordinates onto the aperture surface and performing ellipse geometric fitting on the aperture edge curve surface, the aperture diameter can be measured.
Article
Optics
Jing Luo, Shuo Li, Erik Forsberg, Sailing He
Summary: A 4D surface shape measurement system combining spectral detection and 3D surface morphology measurements is proposed, achieving high spectral resolution and depth accuracy. The system integrates precise spectral data and target morphology reconstruction using a structured light stereovision system, demonstrating excellent performance with a spectral resolution of 3 nm and depth accuracy of 27.5 μm.
Article
Optics
Junfeng Chen, Jingjing Bai, Yunpeng Cheng, Yunpeng Ma, Qingwu Li
Summary: In this study, a novel LiDAR-assisted accuracy improvement strategy for binocular visual measurement is proposed. Calibration between LiDAR and binocular camera is achieved by aligning 3D points cloud and 2D images using the Perspective-n-Point (PNP) algorithm. A nonlinear optimization function and depth-optimization strategy are established to reduce the error of binocular depth. Experimental results demonstrate that our strategy can improve the depth accuracy of binocular visual measurement compared to three stereo matching methods, with the mean error decreasing from 33.46% to 1.70% at different distances.
Article
Engineering, Multidisciplinary
Kimiya Azimbeik, Seyed Hossein Mahdavi, Fayaz Rahimzadeh Rofooei
Summary: The aim of this study is to enhance image-based, full-field displacement measurement using new template-matching and camera-calibration methods. Practical methods to increase the number of pixels in the images, using free markers and improving camera-calibration methods are also investigated.
Article
Optics
Liuning Gu, Wenwu Chen, Xiaohan Hu, Zixiang Tong, Xinxing Shao
Summary: In this study, a binocular camera refractive imaging model was established and a calibration method for the refraction parameters was proposed for accurate three-dimensional visual measurements in deep-water environments. The results of underwater experiments showed the effectiveness of the method.
Article
Automation & Control Systems
Anh-Tuan Dang, Quang-Cherng Hsu, Tat-Tai Truong
Summary: The study proposes a method for reconstructing two-dimensional profiles of ring-shaped objects using image processing, creating a point cloud for automatic measurement with favorable correlation to data from the ATOS measurement system.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2021)