camera-calibration | 易学教程

OpenCV extrinsic camera from feature points

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问题 How do I retrieve the rotation matrix, the translation vector and maybe some scaling factors of each camera using OpenCV when I have pictures of an object from the view of each of these cameras? For every picture I have the image coordinates of several feature points. Not all feature points are visible in all of the pictures. I want to map the computed 3D coordinates of the feature points of the object to a slightly different object to align the shape of the second object to the first object.

Kinect intrinsic parameters from field of view

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问题 Microsoft state that the field of view angles for the Kinect are 43 degrees vertical and 57 horizontal (stated here) . Given these, can we calculate the intrinsic parameters i.e. focal point and centre of projection? I assume centre of projection can be given as (0,0,0)? Thanks EDIT: some more information on what I'm trying to do I have a dataset of images recorded with a Kinect, I am trying to convert pixel positions (x_screen,y_screen and z_world (in mm)) to real world coordinates. If I

OpenCV: get perspective matrix from translation & rotation

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问题 I'm trying to verify my camera calibration, so I'd like to rectify the calibration images. I expect that this will involve using a call to warpPerspective but I do not see an obvious function that takes the camera matrix, and the rotation and translation vectors to generate the perspective matrix for this call. Essentially I want to do the process described here (see especially the images towards the end) but starting with a known camera model and pose. Is there a straightforward function

Python Opencv SolvePnP yields wrong translation vector

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I am attempting to calibrate and find the location and rotation of a single virtual camera in Blender 3d using homography. I am using Blender so that I can double check my results before I move on to the real world where that is more difficult. I rendered ten pictures of a chess board in various locations and rotations in the view of my stationary camera. With OpenCV's Python, I used cv2.calibrateCamera to find the intrinsic matrix from the detected corners of the chess board in the ten images and then used that in cv2.solvePnP to find the extrinsic parameters(translation and rotation).

Transformation of 3D objects related to vanishing points and horizon line

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问题 I\'m trying to computing the exact prospective transformation of a 3D object starting from a vanishing points and horizon line of a picture. What I want is, fixed the vanishing points and horizontal line of a picture, I want rotate and skew an 3D object according with vanishing points and horizontal lines that I set starting from the picture Below the final result that I expected. How can I obtain this result? What kind of transformation can I use? In this video is possibile to see the result

Python Opencv SolvePnP yields wrong translation vector

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问题 I am attempting to calibrate and find the location and rotation of a single virtual camera in Blender 3d using homography. I am using Blender so that I can double check my results before I move on to the real world where that is more difficult. I rendered ten pictures of a chess board in various locations and rotations in the view of my stationary camera. With OpenCV\'s Python, I used cv2.calibrateCamera to find the intrinsic matrix from the detected corners of the chess board in the ten

Computing x,y coordinate (3D) from image point

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问题 I have a task to locate an object in 3D coordinate system. Since I have to get almost exact X and Y coordinate, I decided to track one color marker with known Z coordinate that will be placed on the top of the moving object, like the orange ball in this picture: First, I have done the camera calibration to get intrinsic parameters and after that I used cv::solvePnP to get rotation and translation vector like in this following code: std::vector<cv::Point2f> imagePoints; std::vector<cv::Point3f

How to verify the correctness of calibration of a webcam?

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问题 I am totally new to camera calibration techniques... I am using OpenCV chessboard technique... I am using a webcam from Quantum... Here are my observations and steps.. I have kept each chess square side = 3.5 cm. It is a 7 x 5 chessboard with 6 x 4 internal corners. I am taking total of 10 images in different views/poses at a distance of 1 to 1.5 m from the webcam. I am following the C code in Learning OpenCV by Bradski for the calibration. my code for calibration is cvCalibrateCamera2(object

How to verify the correctness of calibration of a webcam?

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I am totally new to camera calibration techniques... I am using OpenCV chessboard technique... I am using a webcam from Quantum... Here are my observations and steps.. I have kept each chess square side = 3.5 cm. It is a 7 x 5 chessboard with 6 x 4 internal corners. I am taking total of 10 images in different views/poses at a distance of 1 to 1.5 m from the webcam. I am following the C code in Learning OpenCV by Bradski for the calibration. my code for calibration is cvCalibrateCamera2(object_points,image_points,point_counts,cvSize(640,480),intrinsic_matrix,distortion_coeffs,NULL,NULL,CV_CALIB