In one example, a method of motion detection includes producing a first image based on a plurality of previous images, the first image including pixels having intensity values that approximate a difference in intensity values between a pair of pixels within the previous images, and the pair of pixels being one pixel from each of first and second previous images and present at the same locations within their respective images, generating a second image by applying a threshold to the first image, the second image including one or more pixels with intensity values above the threshold, the threshold being derived from intensity values of pixels within the first image and a number of pixels in the first image with a respective intensity value, and determining a region of the second image indicating motion based on a location of the one or more pixels in the second image.