1. A method of determining a depth measurement of a scene using an optical blur difference between two images of the scene, each image being captured using an image capture device with different image capture device parameters, the method comprising: identifying a corresponding image patch from each of the captured images, motion blur being present in each of the image patches and the corresponding image patch for each of the captured images being at least a portion of the respective captured image of each of the captured images; determining a kernel of the motion blur in each of the image patches, the kernel of the motion blur in at least one of the image patches being used to generate a difference convolution kernel; convolving a selected first image patch with the generated difference convolution kernel to generate a modified image patch; and determining a depth measurement of the scene from an optical blur difference between the modified image patch and the remaining image patch.