4User preference test results “The observer data indicates that six of the observers rankedFreeman’s algorithm as the most preferred of the five testedalgorithms. However the other two observers rank Freeman’s algorithmas the least preferred of all the algorithms….Freeman’s algorithm produces prints which are by far the sharpestout of the five algorithms. However, this sharpness comes at a priceof artifacts (spurious detail that is not present in the originalscene). Apparently the two observers who did not prefer Freeman’salgorithm had strong objections to the artifacts. The other observersapparently placed high priority on the high level of sharpness in theimages created by Freeman’s algorithm.”
15Motion analysis: related work Markov networkLuettgen, Karl, Willsky and collaborators.Neural network or learning-basedNowlan & T. J. Senjowski; Sereno.Optical flow analysisWeiss & Adelson; Darrell & Pentland; Ju, Black & Jepson; Simoncelli; Grzywacz & Yuille; Hildreth; Horn & Schunk; etc.
16Motion estimation results Inference:Motion estimation results(maxima of scene probability distributions displayed)Image dataInitial guesses only show motion at edges.Iterations 0 and 1
17Motion estimation results (maxima of scene probability distributions displayed)Iterations 2 and 3Figure/ground still unresolved here.
18Motion estimation results (maxima of scene probability distributions displayed)Iterations 4 and 5Final result compares well with vector quantized true (uniform) velocities.
20Forming an Image Illuminate the surface to get: Surface (Height Map) Shading ImageSurface (Height Map)The shading image is the interaction of the shapeof the surface and the illumination
21Painting the Surface Scene Image Add a reflectance pattern to the surface. Points inside the squares should reflect less light
22Problem What if we want to do shape from shading? ImageHeight MapNeed some mechanism of informing theshape from shading algorithm about thereflectance pattern.
23Represent Scene As=ImageShading ImageReflectance ImageThese types of images are known as intrinsic images (Barrow and Tenenbaum)
24Not Just for Shape from Shading Ability to reason about shading and reflectance independently is necessary for most image understanding tasksMaterial recognitionImage segmentationIntrinsic images are a convenient representation of the sceneLess complex than fully reconstructing the scene