But this position is not expressed in terms of pixel coordinates. We already talked about the perspective projection process, which is used to convert the position of that point in 3D space to a position on the surface of the image. When a point or vertex is defined in the scene and is visible to the camera, the point appears in the image as a dot (or, more precisely, as a pixel if the image is digital). Finding the 2D Pixel Coordinates of a 3D Point: Explained from Beginning to End Mathematics of Computing the 2D Coordinates of a 3D Point Reading time: 37 mins.

Mathematics of Computing the 2D Coordinates of a 3D Point.