camera-calibration

问题 I can use FindChessboardCorners functions for images that less than 15 Mega pixel such like 2k x 1.5k. however when I use it on the image from DSLR, the resolution at 3700x5300, it doesn't work. I tried to use resize() to reduce the image size directly, then it works. Obviously there's some hard coded or bug in the OpenCV source code. Could you help me to figure it out, or point me to a patch for this ? I found someone posted a similar issue in 2006, here, so it looks like the problem still

问题 I have a 4x4 projection matrix (SCNMatrix4) s = (m11 = 1.83226573, m12 = 0, m13 = 0, m14 = 0, m21 = 0, m22 = 2.44078445, m23 = 0, m24 = 0, m31 = -0.00576340035, m32 = -0.0016724075, m33 = -1.00019991, m34 = -1, m41 = 0, m42 = 0, m43 = -0.20002, m44 = 0) I would like to get the focal point and the focal length out of this matrix. 回答1: From slides 4 and 5 on this GDC presentation: The focal length is merely the first element in the matrix ( m11 ). The focal point , however, cannot be extracted

问题 I'm trying to obtain a 3x3 rotation matrix and a focal length parameter in a constrained projection camera model: formula to relate pixel coordinates to real world coordinates: The 3x4 matrix that describe both intrinsic and extrinsic parameters so in my constrained camera model, u0 and v0 are set to 1, Tx, Tv, Tz are set to 0, so the DOF of this is reduced 4 DOF (3 DOF from rotation matrix + 1 DOF for the focal length (au, av)). My problem is, although I know the rotation matrix is

问题 Is it possible to get principal point (cx, cy) from a 4x4 projection matrix? This is the same matrix asked in this question: Getting focal length and focal point from a projection matrix (SCNMatrix4) s = (m11 = 1.83226573, m12 = 0, m13 = 0, m14 = 0, m21 = 0, m22 = 2.44078445, m23 = 0, m24 = 0, m31 = -0.00576340035, m32 = -0.0016724075, m33 = -1.00019991, m34 = -1, m41 = 0, m42 = 0, m43 = -0.20002, m44 = 0) The values I'm trying to calculate in this 3x3 camera matrix is x0 and y0. 来源： https:/

问题 I want to get pictures from: fnumber=6.3; iso_list=[100,200,300,400,500,600,700,800]; shutterspeed_list=[1,1/2,1/3,1/4,1/5,1/6]; Choose the best pair iso and shutterspeed to get picture with appropriate brightness (the brightness=150.0) based on the exposure value. I think i can solve like this: Set the desired_brightness=150.0 ,get the current_brightness based on the picture Get the current iso and shutterspeed ,calculate the current_ev brightness_ratio=log2(desired_brightness)/log2(current

问题 I am programming a code in python that compare the detected object size in the image in pixels with its actual physical dimensions from different distances in a way that I know the focal length, distance and digital sensor of the camera. I am looking for a solution which gives me the physical dimension if I give the object size in pixel in the captured image, then know the distance to the camera and focal length. Then I would like to compare that calculate physical dimension with the actual

问题 Can anyone know what is going on with this opencv error ? cv2.error: /home/desktop/OpenCV/opencv/modules/core/src/matrix.cpp:2294: error: (-215) d == 2 && (sizes[0] == 1 || sizes[1] == 1 || sizes[0]*sizes[1] == 0) in function create Line code which raise it is : rvecs, tvecs, inliers = cv2.solvePnPRansac(objp, corners2, cameraMatrix, dist) I followed step by step this tutorial: http://docs.opencv.org/master/dc/dbb/tutorial_py_calibration.html It seems that cameraMatrix is incorrect, but why ?

问题 I am calibrating my camera and I get quite bad results. As of now, I blame that my camera is bad or I am doing something wrong. The main functions I use are: findChessboardCorners , cornerSubPix , findCirclesGrid , calibrateCamera and solvePnP (as very well described in the opencv documentation for camera calibration) So I started to evaluate how the algorithm for camera calibration works if I add 'perfect' data. I used 3D CAD modelling software (Rhinoceros3D) and modelled my grids with

问题 I want to extract a depth map from a calibrated image and triangular mesh using OpenCV called from Matlab 2014b (using the OpenCV bindings). I am a regular user of Matlab but am new to OpenCV. I have the following inputs: im - an undistorted RGB image of the scene or - camera position vector R - rotation matrix describing camera pose points - nx3 triangular mesh vertex list representing the scene faces - mx3 triangular mesh face list EFL - image effective focal length in pixels I have written

问题 I am using opencv to calibrate my webcam. So, what I have done is fixed my webcam to a rig, so that it stays static and I have used a chessboard calibration pattern and moved it in front of the camera and used the detected points to compute the calibration. So, this is as we can find in many opencv examples (https://docs.opencv.org/3.1.0/dc/dbb/tutorial_py_calibration.html) Now, this gives me the camera intrinsic matrix and a rotation and translation component for mapping each of these