Colour-based object detection, inverse kinematics algorithms and pinhole camera model for controlling robotic arm movement system

Colour-based computer vision algorithm allows to rather precisely distinguish a number of objects disposed on an input camera frame provided that their colours differ from that of a background. Once the border of an object is detected the position of its approximate mass centre may be easily obtained. That coordinate is considered within 2D frame image coming directly from the camera and is subsequently projected to the reference frame associated with the real world by making use of the pinhole camera model and homogeneous coordinates. Given appropriate real world coordinates of the object (which is believed to be put onto a flat plane) iterative Jacobian inverse method provides efficient solution to the problem of inverse kinematics. Thus derived solution is sent to the Arduino microcontroller which in its turn rotates servo joints of the arm by means of the pulse-width modulation (PWM) technique.