Without any extra assumption on the world scene geometry, you cannot affirm that there is a projective transformation between the two views. This is only true if the scene is planar. A good reference on that topic is the book Multiple View Geometry in Computer Vision by Hartley and Zisserman. If the world scene is … Read more
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 and which I recommend getting if you would like more background on this: … Read more
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 4×4 matrix, which is then used to transform each vertex into the so-called clip space. There, testing if … Read more