The weather changes all the time, but the image of velocity had its basic law. Maybe we complicate the law sometimes. In fact, the velocity image can be divided into two parts: positive velocity part and negative velocity part. If the positive area and negative area are the object's feature, for velocity ambiguity area of the first time, just like the object overturned its feature. In order to solve the velocity ambiguity problem, we need to start our work from the zero velocity line, try to find a new way from this clue.
The method mentioned in this article is based on the correct judgment of human beings, using computer to analysis and rectify ambiguous area which is selected by human beings, then get the correct velocity information. We use MFC to design the man-computer conversation interface and provide two kinds of tools, one is magic stick and another is area selection. They are so convenient and results from many different examples indicate that this method needs less time, the correction is more than 99%. This is a great improvement on the traditional complicated human-computer method, and can be used in practice. More over, it provides convenience in scientific research for giving correct velocity information.