An image processing apparatus and method for real time motion detection is provided. In the apparatus, a sub-sampling module receives and sub-samples a current image and a plurality of previous images and a census transform module performs census transform on each of the sub-sampled images to obtain a census vector. A correlation calculation module calculates and compares correlation values between the current image and the plurality of previous images and detects a region having highest correlation. A motion detection module tracks positions of pixels corresponding to the region having the highest correlation to detect motion information in the images. The image processing apparatus and method can obtain, in real time, the direction and speed of an object that is in motion in each image.