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date | Wed, 10 Apr 2013 16:49:05 -0400 |
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1 When I write my thesis, I want it to have links to every5 * Object Recognition from Local Scale-Invariant Features, David G. Lowe7 This is the famous SIFT paper that is mentioned everywhere.9 This is a way to find objects in images given an image of that10 object. It is moderately risistant to variations in the sample image11 and the target image. Basically, this is a fancy way of picking out12 a test pattern embedded in a larger pattern. It would fail to learn13 anything resembling object categories, for instance. Usefull concept14 is the idea of storing the local scale and rotation of each feature15 as it is extracted from the image, then checking to make sure that16 proposed matches all more-or-less agree on shift, rotation, scale,17 etc. Another good idea is to use points instead of edges, since18 they seem more robust.20 ** References:21 - Basri, Ronen, and David. W. Jacobs, “Recognition using region22 correspondences,” International Journal of Computer Vision, 25, 223 (1996), pp. 141–162.25 - Edelman, Shimon, Nathan Intrator, and Tomaso Poggio, “Complex26 cells and object recognition,” Unpublished Manuscript, preprint at27 http://www.ai.mit.edu/edelman/mirror/nips97.ps.Z29 - Lindeberg, Tony, “Detecting salient blob-like image structures30 and their scales with a scale-space primal sketch: a method for31 focus-of-attention,” International Journal of Computer Vision, 11, 332 (1993), pp. 283–318.34 - Murase, Hiroshi, and Shree K. Nayar, “Visual learning and35 recognition of 3-D objects from appearance,” International Journal36 of Computer Vision, 14, 1 (1995), pp. 5–24.38 - Ohba, Kohtaro, and Katsushi Ikeuchi, “Detectability, uniqueness,39 and reliability of eigen windows for stable verification of40 partially occluded objects,” IEEE Trans. on Pattern Analysis and41 Machine Intelligence, 19, 9 (1997), pp. 1043–48.43 - Zhang, Z., R. Deriche, O. Faugeras, Q.T. Luong, “A robust44 technique for matching two uncalibrated images through the recovery45 of the unknown epipolar geometry,” Artificial Intelligence, 78,46 (1995), pp. 87-119.52 * Alignment by Maximization of Mutual Information, Paul A. Viola54 PhD Thesis recommended by Winston. Describes a system that is able55 to align a 3D computer model of an object with an image of that56 object.58 - Pages 9-19 is a very adequate intro to the algorithm.60 - Has a useful section on entropy and probability at the beginning61 which is worth reading, especially the part about entropy.63 - Differential entropy seems a bit odd -- you would think that it64 should be the same as normal entropy for a discrete distrubition65 embedded in continuous space. How do you measure the entropy of a66 half continuous, half discrete random variable? Perhaps the67 problem is related to the delta function, and not the definition68 of differential entropy?70 - Expectation Maximation (Mixture of Gaussians cool stuff)71 (Dempster 1977)73 - Good introduction to Parzen Window Density Estimation. Parzen74 density functions trade construction time for evaulation75 time.(Pg. 41) They are a way to transform a sample into a76 distribution. They don't work very well in higher dimensions due77 to the thinning of sample points.79 - Calculating the entropy of a Markov Model (or state machine,80 program, etc) seems like it would be very hard, since each trial81 would not be independent of the other trials. Yet, there are many82 common sense models that do need to have state to accurately model83 the world.85 - "... there is no direct procedure for evaluating entropy from a86 sample. A common approach is to model the density from the sample,87 and then estimate the entropy from the density."89 - pg. 55 he says that infinity minus infinity is zero lol.91 - great idea on pg 62 about using random samples from images to92 speed up computation.94 - practical way of terminating a random search: "A better idea is to95 reduce the learning rate until the parameters have a reasonable96 variance and then take the average parameters."98 - p. 65 bullshit hack to make his parzen window estimates work.100 - this alignment only works if the initial pose is not very far101 off.104 Occlusion? Seems a bit holistic.106 ** References107 - "excellent" book on entropy (Cover & Thomas, 1991) [Elements of108 Information Theory.]110 - Canny, J. (1986). A Computational Approach to Edge Detection. IEEE111 Transactions PAMI, PAMI-8(6):679{698113 - Chin, R. and Dyer, C. (1986). Model-Based Recognition in Robot114 Vision. Computing Surveys, 18:67-108.116 - Grimson, W., Lozano-Perez, T., Wells, W., et al. (1994). An117 Automatic Registration Method for Frameless Stereotaxy, Image118 Guided Surgery, and Enhanced Realigy Visualization. In Proceedings119 of the Computer Society Conference on Computer Vision and Pattern120 Recognition, Seattle, WA. IEEE.122 - Hill, D. L., Studholme, C., and Hawkes, D. J. (1994). Voxel123 Similarity Measures for Auto-mated Image Registration. In124 Proceedings of the Third Conference on Visualization in Biomedical125 Computing, pages 205 { 216. SPIE.127 - Kirkpatrick, S., Gelatt, C., and Vecch Optimization by Simulated128 Annealing. Science, 220(4598):671-680.130 - Jones, M. and Poggio, T. (1995). Model-based matching of line131 drawings by linear combin-ations of prototypes. Proceedings of the132 International Conference on Computer Vision134 - Ljung, L. and Soderstrom, T. (1983). Theory and Practice of135 Recursive Identi cation. MIT Press.137 - Shannon, C. E. (1948). A mathematical theory of communication. Bell138 Systems Technical Journal, 27:379-423 and 623-656.140 - Shashua, A. (1992). Geometry and Photometry in 3D Visual141 Recognition. PhD thesis, M.I.T Artificial Intelligence Laboratory,142 AI-TR-1401.144 - William H. Press, Brian P. Flannery, S. A. T. and Veterling,145 W. T. (1992). Numerical Recipes in C: The Art of Scienti c146 Computing. Cambridge University Press, Cambridge, England, second147 edition edition.149 * Semi-Automated Dialogue Act Classification for Situated Social Agents in Games, Deb Roy151 Interesting attempt to learn "social scripts" related to resturant152 behaviour. The authors do this by creating a game which implements a153 virtual restruant, and recoding actual human players as they154 interact with the game. The learn scripts from annotated155 interactions and then use those scripts to label other156 interactions. They don't get very good results, but their157 methodology of creating a virtual world and recording158 low-dimensional actions is interesting.160 - Torque 2D/3D looks like an interesting game engine.163 * Face Recognition by Humans: Nineteen Results all Computer Vision Researchers should know, Sinha165 This is a summary of a lot of bio experiments on human face166 recognition.168 - They assert again that the internal gradients/structures of a face169 are more important than the edges.171 - It's amazing to me that it takes about 10 years after birth for a172 human to get advanced adult-like face detection. They go through173 feature based processing to a holistic based approach during this174 time.176 - Finally, color is a very important cue for identifying faces.178 ** References179 - A. Freire, K. Lee, and L. A. Symons, BThe face-inversion effect as180 a deficit in the encoding of configural information: Direct181 evidence,[ Perception, vol. 29, no. 2, pp. 159–170, 2000.182 - M. B. Lewis, BThatcher’s children: Development and the Thatcher183 illusion,[Perception, vol. 32, pp. 1415–21, 2003.184 - E. McKone and N. Kanwisher, BDoes the human brain process objects185 of expertise like faces? A review of the evidence,[ in From Monkey186 Brain to Human Brain, S. Dehaene, J. R. Duhamel, M. Hauser, and187 G. Rizzolatti, Eds. Cambridge, MA: MIT Press, 2005.192 heee~eeyyyy kids, time to get eagle'd!!!!198 * Ullman200 Actual code reuse!202 precision = fraction of retrieved instances that are relevant203 (true-postives/(true-positives+false-positives))205 recall = fraction of relevant instances that are retrieved206 (true-positives/total-in-class)208 cross-validation = train the model on two different sets to prevent209 overfitting.211 nifty, relevant, realistic ideas212 He doesn't confine himself to unplasaubile assumptions214 ** Our Reading215 *** 2002 Visual features of intermediate complexity and their use in classification220 ** Getting around the dumb "fixed training set" methods222 *** 2006 Learning to classify by ongoing feature selection224 Brings in the most informative features of a class, based on225 mutual information between that feature and all the examples226 encountered so far. To bound the running time, he uses only a227 fixed number of the most recent examples. He uses a replacement228 strategy to tell whether a new feature is better than one of the229 corrent features.231 *** 2009 Learning model complexity in an online environment233 Sort of like the heirichal baysean models of Tennanbaum, this234 system makes the model more and more complicated as it gets more235 and more training data. It does this by using two systems in236 parallell and then whenever the more complex one seems to be237 needed by the data, the less complex one is thrown out, and an238 even more complex model is initialized in its place.240 He uses a SVM with polynominal kernels of varying complexity. He241 gets good perfoemance on a handwriting classfication using a large242 range of training samples, since his model changes complexity243 depending on the number of training samples. The simpler models do244 better with few training points, and the more complex ones do245 better with many training points.247 The final model had intermediate complexity between published248 extremes.250 The more complex models must be able to be initialized efficiently251 from the less complex models which they replace!254 ** Non Parametric Models256 *** 2010 The chains model for detecting parts by their context258 Like the constelation method for rigid objects, but extended to259 non-rigid objects as well.261 Allows you to build a hand detector from a face detector. This is262 usefull because hands might be only a few pixels, and very263 ambiguous in an image, but if you are expecting them at the end of264 an arm, then they become easier to find.266 They make chains by using spatial proximity of features. That way,267 a hand can be idntified by chaining back from the head. If there268 is a good chain to the head, then it is more likely that there is269 a hand than if there isn't. Since there is some give in the270 proximity detection, the system can accomodate new poses that it271 has never seen before.273 Does not use any motion information.275 *** 2005 A Hierarchical Non-Parametric Method for Capturing Non-Rigid Deformations277 (relative dynamic programming [RDP])279 Goal is to match images, as in SIFT, but this time the images can280 be subject to non rigid transformations. They do this by finding281 small patches that look the same, then building up bigger282 patches. They get a tree of patches that describes each image, and283 find the edit distance between each tree. Editing operations284 involve a coherent shift of features, so they can accomodate local285 shifts of patches in any direction. They get some cool results286 over just straight correlation. Basically, they made an image287 comparor that is resistant to multiple independent deformations.289 !important small regions are treated the same as nonimportant290 small regions292 !no conception of shape294 quote:295 The dynamic programming procedure looks for an optimal296 transformation that aligns the patches of both images. This297 transformation is not a global transformation, but a composition298 of many local transformations of sub-patches at various sizes,299 performed one on top of the other.301 *** 2006 Satellite Features for the Classification of Visually Similar Classes303 Finds features that can distinguish subclasses of a class, by304 first finding a rigid set of anghor features that are common to305 both subclasses, then finding distinguishing features relative to306 those subfeatures. They keep things rigid because the satellite307 features don't have much information in and of themselves, and are308 only informative relative to other features.310 *** 2005 Learning a novel class from a single example by cross-generalization.312 Let's you use a vast visual experience to generate a classifier313 for a novel class by generating synthetic examples by replaceing314 features from the single example with features from similiar315 classes.317 quote: feature F is likely to be useful for class C if a similar318 feature F proved effective for a similar class C in the past.320 Allows you to trasfer the "gestalt" of a similiar class to a new321 class, by adapting all the features of the learned class that have322 correspondance to the new class.324 *** 2007 Semantic Hierarchies for Recognizing Objects and Parts326 Better learning of complex objects like faces by learning each327 piece (like nose, mouth, eye, etc) separately, then making sure328 that the features are in plausable positions.