Measurement angular velocity based on video technology

Traditional method to measure rotational speed of object is to install some devices on the object, such as rotary encoder etc. However, some objects cannot be installed with any measuring equipment. Sometimes, the owner of the objects does not allow such installment. To measure the angular velocity of the object with video measurement technique is a possible alternative, which is the goal of this study. The angular velocity of the object can be measured firstly by a camera to record rotational video of the objects and then two adjacent frames can be extracted from the video. Hough transform (or Radon transform) is applied to detect the straight line in the images, and calculate the angular of the lines in each image. In this way, the value of difference angle between two frames can be calculated. It is easy to get the angular velocity of the object because the interval time of the two frames is known. The experiment confirmed that this method can get an ideal measurement results.