Reseach On Digital Light Field Photography Based On Microlens Array

Light field imaging as a new direction of imaging technology can refocuse images after an exposure, by computer processing rather than mechanical focus. It can also achieve 3D restruction and improve depth of field. These advantages will promote development of light field imaging in many industries.In this paper, the traditional plenoptic camera, which is achieved by inserting a microlens array between the sensor and the main lens in the traditional camera are investigated. This process using the plenoptic camera is light field photography. It can capture both spatial(or position) and angular(or direction) information, i.e., the full four-dimensional radiance, of a scene in a single photographic exposure. The hand-held plenoptic camera appeared in 2005, which is also called the plenoptic 1.0 camera, and the microlens array is fixed a microlens’ focal length in front of the image sensor. Then the camera focuses the main lens on the microlenses at infinity.Each microlens measures not just the total amount of light deposited at that location, but how much light arrives along each ray. Thus by re-sorting the measured rays of light to where they would have terminated in slightly different, synthetic cameras, We can achieve sharp refocused photographs. However, the resolution of photographs in this device is influenced by the number of the microlens. Only a single pixel in the final image can be rendered from each microlens image when refocusing, thus pixel of the refocused photographs is the same number as microlens. Number of microlens can only be hundreds duo to the manufacture technology, so for a mega-pixels CCD, pixel utilization percentage is just a small percentage of image sensor pixels, resulting a low resolution image.In order to improve the image resolution, the plenoptic 2.0(or the focused plenoptic) is put forward, in which the main camera lens are focused well in front of the microlenses and the microlenses are focused on the image formed inside the camera, rather than in the main lens plane-i.e. Each microlens forms a relay system with the main camera lens. This configuration produces a flexible trade-off in the sampling of spatial and angular dimensions and enables positional information in the radiance to be sampled more effectively. As a result, the plenoptic 2.0 camera can produce images of much higher resolution than can traditional plenoptic cameras.We present full resolution rendering to analyze photographs captured by the focused plenoptic camera, then will present the processing of rendering and the main points of this method. Meanwhile, we will show you the result image by every step. At the same time, the angular(or direction) information will be fully used to get different perspective images. According the different perspective figure, we can calculate the depth map, then achieve the full resolution image. This processing is according to improve the depth of field. In a word, full resolution rendering algorithms of the plenoptic 2.0 can produce high-quality, high-resolution images, allowing us to render high resolution images that meet the expectations of modern photographers. This paper presents the experimental device, some improving methods and a description of the software interface. At last, we summarize the paper and point to our limitations and the future directions.