[ros-users] [Discourse.ros.org] [Computer Vision / Perception] How to project 3D data into pixel coordinate?

[Mehdi Tlili]

You don't need a library for that, just use the [pinhole camera model](https://en.wikipedia.org/wiki/Pinhole_camera_model) 
here is a small python function:
def world_to_pixel(self, point):
    x = point[0]
    y = point[1]
    z = point[2]
    px = x*self.K[0][0]/z + self.K[0][2]
    py = y*self.K[1][1]/z + self.K[1][2]
    return np.asarray([px, py])

K is the 3x3 camera matrix you get from camera_info
    self.K[0][0] = cam_info.K[0]
    self.K[0][2] = cam_info.K[2]
    self.K[1][1] = cam_info.K[4]
    self.K[1][2] = cam_info.K[5]
    self.K[2][2] = 1





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