A calibrated-pinhole camera model for single viewpoint omnidirectional imaging systems

2005 ◽  
Author(s):  
D. Moldovan ◽  
T. Wada
Keyword(s):  
Pinhole Camera ◽  
Imaging Systems ◽  
Camera Model ◽  
Omnidirectional Imaging

Determining Intrinsic Parameters and Pose of Cameras from Single View with Variable Focal Length

2014 ◽  
Vol 635-637 ◽  
pp. 1011-1017
Author(s):  
Gui Hua Liu ◽  
Hui Min Long
Keyword(s):  
Focal Length ◽  
Pinhole Camera ◽  
Projection Matrix ◽  
Camera Model ◽  
Intrinsic Parameter ◽  
Simulation Data ◽  
Single View ◽  
Estimated Parameters ◽  
Orientation Matrix ◽  
Camera Location

This study claims an algorithm of calibration which is executed on the basis of projection matrix. This algorithm directly estimates intrinsic parameter on the basis of rotation matrix’s unitary orthogonality combined with Cholesky decomposition from the obtained projection matrix. Then, false is excluded by rotation matrix’s determinant constraints, and ultimately, camera location and orientation matrix are obtained and estimated parameters are optimized with the minimum error of reprojection residual being cost function. This algorithm is taken under a pinhole camera model and can calibrate the camera from single view with variable focal length. Both simulation data and true image experiments have proved the feasibility and robustness of this algorithm.

A Flexible Pinhole Camera Model for Coherent Nonuniform Sampling

2014 ◽  
Vol 34 (4) ◽  
pp. 30-41
Author(s):  
Voicu Popescu ◽  
Bedrich Benes ◽  
Paul Rosen ◽  
Jian Cui ◽  
Lili Wang
Keyword(s):  
Nonuniform Sampling ◽  
Pinhole Camera ◽  
Camera Model

Camera Calibration Technique Based on HALCON Machine Vision

2013 ◽  
Vol 365-366 ◽  
pp. 666-671
Author(s):  
Xue Ping Liu ◽  
Yi Chang Chen ◽  
Zu Fu Pang
Keyword(s):  
Machine Vision ◽  
Camera Calibration ◽  
Pinhole Camera ◽  
Camera Model ◽  
Calibration Technique ◽  
Distortion Factor ◽  
Full Account ◽  
Practical Applications ◽  
Model Instance ◽  
Cross Platform

According to the perspective projection performed by a pinhole camera, taking full account of the lens radial distortion factor, the transformation between the camera coordinate has been analyzed. Combining with camera model instance of surface mount devices, the system uses Halcon machine vision software which has a powerful geometric and image computing functions to solve the camera calibration parameters and the accuracy of calibration results has been verified in practical applications. This method has advantages of computational efficiency and good value of cross-platform porting applications.

Soft-prototyping imaging systems for oral cancer screening

2020 ◽  
Vol 2020 (7) ◽  
pp. 212-1-212-7
Author(s):  
Joyce Farrell ◽  
Zheng Lyu ◽  
Zhenyi Liu ◽  
Henryk Blasinski ◽  
Zhihao Xu ◽  
...  
Keyword(s):  
Cancer Screening ◽  
Oral Cancer ◽  
Digital Camera ◽  
Imaging Systems ◽  
Spectral Radiance ◽  
Camera Model ◽  
Tissue Fluorescence ◽  
Oral Cancer Screening ◽  
Systems Simulation ◽  
Precancerous Tissue

We are using image systems simulation technology to design a digital camera for measuring fluorescent signals; a first application is oral cancer screening. We validate the simulations by creating a camera model that accurately predicts measured RGB values for any spectral radiance. Then we use the excitationemission spectra for different biological fluorophores to predict measurements of fluorescence of oral mucosal tissue under several different illuminations. The simulations and measurements are useful for (a) designing cameras that measure tissue fluorescence and (b) clarifying which fluorophores may be diagnostic in identifying precancerous tissue.

scholarly journals Omnigradient Based Total Variation Minimization for Enhanced Defocus Deblurring of Omnidirectional Images

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yongle Li ◽  
Jingtao Lou
Keyword(s):  
Image Processing ◽  
Imaging Systems ◽  
Total Variation Minimization ◽  
Defocus Blur ◽  
Omnidirectional Imaging ◽  
Gradient Computation ◽  
Omnidirectional Image ◽  
3D Scene ◽  
Omnidirectional Images ◽  
Computing Method

We propose a new method of image restoration for catadioptric defocus blur using omnitotal variation (Omni-TV) minimization based on omnigradient. Catadioptric omnidirectional imaging systems usually consist of conventional cameras and curved mirrors for capturing 360° field of view. The problem of catadioptric omnidirectional imaging defocus blur, which is caused by lens aperture and mirror curvature, becomes more severe when high resolution sensors and large apertures are used. In an omnidirectional image, two points near each other may not be close to one another in the 3D scene. Traditional gradient computation cannot be directly applied to omnidirectional image processing. Thus, omnigradient computing method combined with the characteristics of catadioptric omnidirectional imaging is proposed. Following this Omni-TV minimization is used as the constraint for deconvolution regularization, leading to the restoration of defocus blur in an omnidirectional image to obtain all sharp omnidirectional images. The proposed method is important for improving catadioptric omnidirectional imaging quality and promoting applications in related fields like omnidirectional video and image processing.

Measurement of Cam Spacing on Assembled Camshaft Based on Improved Fundamental Matrix Calibration

2013 ◽  
Vol 850-851 ◽  
pp. 241-244
Author(s):  
Guan Nan Li ◽  
Qing Chang Tan ◽  
Si Yuan Liu
Keyword(s):  
Fundamental Matrix ◽  
Ccd Camera ◽  
Calibration Method ◽  
Measurement Model ◽  
Pinhole Camera ◽  
Epipolar Line ◽  
Camera Model ◽  
Distortion Model ◽  
Imaging Model ◽  
Measurement Results

Imaging model of double CCD camera based on pinhole camera model and distortion model is introduced, and the fundamental matrix is presented. Distortion model is led into the fundamental matrix calibration. Based on the imaging model of Z. Zhangs calibration method, fundamental matrix is carried out. Pixel coordinate for calibration is modified by cameras interior parameters and distortion coefficients. Base on the imaging model of double CCD camera, measurement model for cam spacing is established. Cam spacing is measured by the feature of cam edge. In experiments, accurate pixel coordinates of model plane were used in calibration. The distance between a point and its corresponding epipolar line was estimated as the error. The measurement results show that the accuracy of proposed method satisfied the monitoring requirements of the axial positioning error of the cam piece.

Pinhole Camera Model

2014 ◽  
pp. 610-613 ◽  
Author(s):  
Peter Sturm
Keyword(s):  
Pinhole Camera ◽  
Camera Model
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