Recent years have witnessed a strong renewal of interest in light field cameras, as they can capture rich angular information within one snapshot. As a representative application of light field cameras, refocusing can change the in-focus region of images so that objects lying on a specified plane are in focus, whereas objects lying off this plane are blurred. The existing refocusing methods can only project images onto focal planes. In this paper, we proposed a reprojetion-based method to refocus the images captured by camera arrays onto arbitrary focal surfaces, rather than only planes. Combining the camera imaging model and the equation of the focal surface, we can reproject the images onto arbitrary focal surface. We can change the focal surface by changing the equation of the focal surface. Experiments on real-world scenes (captured by our self-developed light field devices) demonstrate the validity of the proposed method.
Light field cameras have drawn much attention due to the advantage of post-capture adjustments such as refocusing after exposure. The depth of field in refocused images is always shallow because of the large equivalent aperture. As a result, a large number of multi-focus images are obtained and an all-in-focus image is demanded. Consider that most multi-focus image fusion algorithms do not particularly aim at large numbers of source images and traditional DWT-based fusion approach has serious problems in dealing with lots of multi-focus images, causing color distortion and ringing effect. To solve this problem, this paper proposes an efficient multi-focus image fusion method based on stationary wavelet transform (SWT), which can deal with a large quantity of multi-focus images with shallow depth of fields. We compare SWT-based approach with DWT-based approach on various occasions. And the results demonstrate that the proposed method performs much better both visually and quantitatively.