Apparatus and method for measuring flow velocity of stream using optical flow image processing

Disclosed is a river flow velocity measurement device using optical flow image processing, including: an image photographing unit configured to acquire consecutive images of a flow velocity measurement site of a river; an image conversion analysis unit configured to dynamically extract frames of the consecutive images in order to normalize image data of the image photographing unit, image-convert the extracted frames, and perform homography calculation; an analysis region extracting unit configured to extract an analysis region of an analysis point; a pixel flow velocity calculating unit configured to calculate a pixel flow velocity using an image in the analysis region of the analysis point extracted by the analysis region extracting unit; and an actual flow velocity calculating unit configured to convert the pixel flow velocity calculated by the pixel flow velocity calculating unit into an actual flow velocity.