William Choe Frank
CS194-26 Proj5

Lightfield Camera

Overview

The goal of this project is to show the capabilities of light field data. A light field grid is a series of images taken by cameras that are placed together on a grid. Because of the close proximities of these cameras, the resulting images contain a lot of light rays that can be combined to create interesting results. These results can be achieved by modifying the enviornment before the photo is taken, but lightfield grid allow us to achieve these results after the photo is taken.

Depth Refocusing

When changing the depth of field, you need to realigning each image before averaging them. We want to change the focal point by shifting images toward the center (the coordinates of the image at (8, 8) because we have a 17 x 17 grid). We do this so the middle image is in focus.

To implement depth refocusing, for a given depth focus I want to acheive, I calculate the new x,y positions x',y' [x',y'] = C[x,y] where c is a weight. A positive C will focus the image closer while a negative C will focus the image farther. Foreach c in the range of C = [-3.0 to 1.0], I shift all images towards the center image (in terms of the lightfield grid, so the image at position (8,8)) with the scheme exlpained above, and then is averaged all together.

Here is the gif of depth refocusing.
part1 chess

Aperture Adjustment

To implement aperture adjustment adjustment, you can average the images around the center (8,8) within a certain radius i.e. 0,1,2,... A smaller window size creates the effect of the smaller aperture size. A larger window size creates the effect of a larger aperture.

part2 chess

Summary

I learned a lot about lightfields and was really amazed at what you can do just given a single lightfield.