perspectivecamera

In the pinhole camera model there is only one focal length which is between the principal point and the camera center. However, after calculating the camera's intrinsic parameters, the matrix contains (fx, 0, offsetx, 0, 0, fy, offsety, 0, 0, 0, 1, 0) Is this because the pixels of the image sensor are not square in x and y? Thank you. FvD In short: yes. In order to make a mathematical model that can describe a camera with rectangular pixels, you have to introduce two separate focal lengths. I'll quote from the often recommended " Learning OpenCV " (p. 373) which covers that section pretty well

I wonder about the gluPerspective parameters. In all examples I see fovy is set to around 45-60degrees I've tried to set it to different values and the object just disappears what's the explanation for it? The aspect value should always be the ratio? why would one change it? zNear, zFar - once again the usual values are around 10 and 500+ what does it reflect? gemse The purpose of the 4 parameters is to define a view frustum , like this: where nothing outside of the frustum should be is visible on screen ( To accomplish this, the parameters are used to calculate a 4x4 matrix, which is then

I'm currently working on an Augmented reality application. The targetted device being an Optical See-though HMD I need to calibrate its display to achieve a correct registration of virtual objects. I used that implementation of SPAAM for android to do it and the result are precise enough for my purpose. My problem is, calibration application give in output a 4x4 projection matrix I could have directly use with OpenGL for exemple. But, the Augmented Reality framework I use only accept optical calibration parameters under the format Field of View some parameter + Aspect Ratio some parameter +

I am trying to recode feature matching and homography using mexopencv .Mexopencv ports OpenCV vision toolbox into Matlab . My code in Matlab using OpenCV toolbox: function hello close all;clear all; disp('Feature matching demo, press key when done'); boxImage = imread('D:/pic/500_1.jpg'); boxImage = rgb2gray(boxImage); [boxPoints,boxFeatures] = cv.ORB(boxImage); sceneImage = imread('D:/pic/100_1.jpg'); sceneImage = rgb2gray(sceneImage); [scenePoints,sceneFeatures] = cv.ORB(sceneImage); if (isempty(scenePoints)|| isempty(boxPoints)) return; end; matcher = cv.DescriptorMatcher('BruteForce');

All matrix libraries for WebGL have some sort of perspective function that you call to get the perspective matrix for the scene. For example, the perspective method within the mat4.js file that's part of gl-matrix is coded as such: mat4.perspective = function (out, fovy, aspect, near, far) { var f = 1.0 / Math.tan(fovy / 2), nf = 1 / (near - far); out[0] = f / aspect; out[1] = 0; out[2] = 0; out[3] = 0; out[4] = 0; out[5] = f; out[6] = 0; out[7] = 0; out[8] = 0; out[9] = 0; out[10] = (far + near) * nf; out[11] = -1; out[12] = 0; out[13] = 0; out[14] = (2 * far * near) * nf; out[15] = 0; return

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. I heard it is possible using cv::calibrateCamera(...) but I can't get quite through it... Does someone

Currently I'm writing an augmented reality app and I have some problems to get the objects on my screen. It's very frustrating for me that I'm not able to transform gps-points to the correspending screen-points on my android device. I've read many articles and many other posts on stackoverflow (I've already asked similar questions) but I still need your help. I did the perspective projection which is explained in wikipedia. What do I have to do with the result of the perspective projection to get the resulting screenpoint? benjaminplanche The Wikipedia article also confused me when I read it