= Assignment 3 Camera Simulation = == Murad Akhter == == Date submitted: 11th May 2006 == == Code emailed: 11th May 2006 == == Compound Lens Simulator == === Description of implementation approach and comments === ...... === Final Images Rendered with 512 samples per pixel === || || '''My Implementation''' || '''Reference''' || || '''Telephoto''' ||attachment:hw3.telephoto_512.png|| http://graphics.stanford.edu/courses/cs348b-06/homework3/hw3.telephoto_512.png|| || '''Double Gausss''' ||attachment:hw3.dgauss_512.png||http://graphics.stanford.edu/courses/cs348b-06/homework3/hw3.dgauss_512.png|| || '''Wide Angle''' ||attachment:hw3.wide_512.png||http://graphics.stanford.edu/courses/cs348b-06/homework3/hw3.wide_512.png|| || '''Fisheye''' ||attachment:hw3.fisheye_512.png||http://graphics.stanford.edu/courses/cs348b-06/homework3/hw3.fisheye_512.png|| === Final Images Rendered with 4 samples per pixel === || || '''My Implementation''' || '''Reference''' || || '''Telephoto''' ||attachment:hw3.telephoto.png|| http://graphics.stanford.edu/courses/cs348b-06/homework3/hw3.telephoto_4.png|| || '''Double Gausss''' ||attachment:hw3.dgauss.png||http://graphics.stanford.edu/courses/cs348b-06/homework3/hw3.dgauss_4.png|| || '''Wide Angle''' ||attachment:hw3.wide.png||http://graphics.stanford.edu/courses/cs348b-06/homework3/hw3.wide_4.png|| || '''Fisheye''' ||attachment:hw3.fisheye.png||http://graphics.stanford.edu/courses/cs348b-06/homework3/hw3.fisheye_4.png|| == Experiment with Exposure == || '''Image with aperture full open''' || '''Image with half radius aperture''' || || attachment:hw3.dgauss_512.png || attachment:dgauss_dim.png || === Observation and Explanation === As is easy to see, the image on the right is dimmer once the aperture size is reduced. The exposure of the image depends on the number of rays that can pass through the lens system unobstructed. Reducing the aperture size by half reduces the area rays can pass through by a quarter. This equals 2 f-stops since one stop corressponds to halving of the light intensity from the previous stop. == Autofocus Simulation == === Description of implementation approach and comments === attachment:bunnies.depth.png === Final Images Rendered with 512 samples per pixel === || || '''Adjusted film distance''' || '''My Implementation''' || '''Reference''' || || '''Double Gausss 1''' || 58.73 mm || attachment:hw3.afdgauss_closeup.png || http://graphics.stanford.edu/courses/cs348b-06/homework3/hw3.afdgauss_closeup.png|| || '''Double Gausss 2''' || 58.73 mm || attachment:hw3.afdgauss_bg.png ||http://graphics.stanford.edu/courses/cs348b-06/homework3/hw3.afdgauss_bg.png|| || '''Telephoto''' || __ mm ||http://graphics.stanford.edu/courses/cs348b-06/homework3/blank300x300.jpg||http://graphics.stanford.edu/courses/cs348b-06/homework3/hw3.aftelephoto.png|| == Extras == === Stopping Down the Telephoto Lens === || '''Image with aperture full open''' || '''Image with quarter diameter aperture''' || '''Exposure increased by 4-stops in Photoshop''' || || attachment:hw3.telephoto_512.png || attachment:hw3.telephoto_lessBright.png || attachment:hw3.telephoto_brightAgain.png || I reduced the aperture to 1/4 th its original value to observe a 4-stop change in exposure. Increasing the exposure in Photoshop gave an image that seemed similar to the original. The reduced aperture size causes the images to be noisier since fewer rays end up making it to the scene from the camera. This is easy to see when comparing the Photoshop image with the original image on the leftmost column. === More Complex Auto Focus === || '''Background''' || '''Normal''' || '''Foreground''' || || attachment:autofocus_test_background.png || attachment:autofocus_test_avg.png || attachment:autofocus_test_foreground.png || Here are results from a similar experiment with the bunnies scene. It's easier to see the difference when the foreground and background focused images are next to each other. Unfortunately as the bunnies ar closely packed, even this comparision isn't very obvious unless you pay attention to the foreground bushes or the distant bunny in the center of the image. || '''Background''' || '''Foreground''' || || attachment:bunnies_background.png || attachment:bunnies_foreground.png || Here's the normal image that is generated if neither mode is selected [[BR]] attachment:bunnies.png