如何从计算机视觉相机计算像素的水平角 [英] how to compute horizontal angle of a pixel from a computer vision camera

问题描述

我的程序需要从具有 120 度水平视野、640 像素宽和 480 像素高的分辨率的计算机视觉相机计算像素的角度.

My program needs to compute the angle of a pixel from a computer vision camera that has 120 degrees horizontal field of view, and resolution of 640 pixels wide and 480 pixels high.

程序从相机接收每个图像帧的 X,Y 像素数组.对于最左边的像素，X 为 0，角度为 -60 度.对于最右边的像素，X 为 639，角度为 60 度.对于中心像素，X 为 320，角度为 0.

Program receives an X,Y array of pixels for each image frame from camera. For left-most pixel, X would be 0 and angle would be -60 degrees. For right-most pixel, X would be 639 and angle 60 degrees. For center pixel, X would be 320 and angle 0.

当 (X is > 0 and < 320) and (>320 and <640) 时，角度如何计算?

How is angle computed when (X is > 0 and < 320) and (>320 and <640)?

推荐答案

// In pseudocode.

// Compute focal length in pixels from FOV
double f = (0.5 * image_width) / tan(0.5 * fov_radians);

// Vectors subtending image center and pixel from optical center
// in camera coordinates.
Vector3D center(0, 0, f), pixel(x - center_x, y - center_y, f);

// angle between vector (0, 0, f) and pixel
double dot = dot_product(center, pixel)
double alpha = acos(dot / (center.length() * pixel.length()));

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