Process and Implementation
Optical Flow
First, I needed to investigate methods to compute optical flow. From the description in the paper, it seemed as if they were using the Lucas-Kanade method. This method assumes that optical flow is constant in a small window. It is a highly used method of computing optical flow and is found in several libraries. The library I utilized was created by Piotr Dollar, from the University of California, San Diego (1). This toolbox also implements a cross-correlation method of computing optical flow, as well as the Horn & Schunck method. I tested all three of these methods and determined that the Lucas-Kanade method was the best choice for this application.
In class, there was a suggestion to investigate a hierarchical version of the Lucas-Kanade method to more accurately calculate optical flow, since it is an integral part of this paper. I tested a toolbox (2) that was written by Sohaib Khan, who was a student of Mubarak Shah at the University of Central Florida. This code produced results that were much more highly susceptible to noise, and I determined that the better choice was the original toolbox. These results can be seen in Figure 1.
Figure 1: Lucas-Kanade Optical Flow Method (left) vs. Hierarchical Lucas-Kanade Optical Flow Method (right)
Generalized Social Force for Particle Advection and Calculation of the Interaction Force
The paper presents a method of using particle advection to estimate the flow of objects through a scene. Since crowd scenes are cluttered and difficult to track microscopically, the authors proposed this macroscopic method of overlaying a grid of particles on the scene and advecting them via optical flow to model the movement of the crowd. This...
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... is unclear and a mystery to me. I also would be interested in implementing the concept in a way other than through particle advection, as I feel that it loses a lot of data by not evenly covering the scene in each clip.
Works Cited
1. Dollar, Piotr. Piotr's Matlab Image and Video Toolbox. Piotr Dollar. [Online] February 22, 2010. [Cited: March 17, 2010.] http://vision.ucsd.edu/~pdollar/toolbox/doc/.
2. Khan, Sohaib. Source Code. Mubarak Shah. [Online] [Cited: March 17, 2010.] http://www.cs.ucf.edu/~vision/Code/Optical_Flow/Lucas%20Kanade.zip.
3. Blei, David. Latent Dirichlet Allocation in C. David Blei. [Online] [Cited: March 17, 2010.] http://www.cs.princeton.edu/~blei/lda-c/index.html.
4. Mochihashi, Daichi. lda, a Latent Dirichlet Allocation package. Daichi Mochihashi. [Online] December 4, 2004. [Cited: March 17, 2010.] http://chasen.org/~daiti-m/dist/lda/.
1.Chapman, Jeff and John D. Jorgenson, eds. "Kesey, Ken." Contemporary Authors Vol.54. Detroit: Gale, 1997.
Tanaka, K., Saito, H. A., Fukada, Y., & Moriya, M. (1991). Coding vidual images of objects
Jean Carletta, “Assessing agreement on classification tasks: The kappa statistic”. Computational Linguistics, MIT Press Cambridge, MA, USA, Vol. 22, No.2, pp. 249–254, 1996.
Weng, Y., Kuo, K.N., Yang, C., Lo, H., Chen, C., & Ya-Wen, C. (2013). Implementation
Surface tension effects in wet particle assemblies cause the Liquid bridge forces. When the particle diameter is 1 mm, then these forces become dominant.
Three dimensional motion capture requires more than one camera to create depth in the motion being performed. A good example is eyesight. If someone where unfortunate enough to only have one eye they would be unable to see the 3-D depth in motion. Having two eyes allows for depth in motion when seeing, which is similar to the idea of using two cameras in order to fully capture the depth in motion. One of the few techniques discovered and used in 3-D motion capture is Direct Linear Transform (DLT). Using the idea that, images from the cameras are determined by their placement to discover their distances, equations could be formed and used. Test subjects wear reflective markers to allow the cameras to follow their movement and motion through space. These reflective markers are placed on certain joins and parts of the body the researcher would like to study. The reflective markers ca...
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Pierre Simon Laplace on Probability and Statistics . (n.d.). In cerebro.xu.edu. Retrieved March 24, 2014, from http://cerebro.xu.edu/math/Sources/Laplace/
...omated detection of lines and points in the images and the use of smart markers in reference video recordings.
Essentially, once an image exists in digital form, it can either be tweaked to adjust even its most indiscernible features or it can be entirely morphed into something altogether different. There ...
In this section, the results of the research are presented. For each task carried out, the most important information obtained is presented.
Large particles are light that are scatterred at small angles relative to the laser beam and small particles scatter light at large angles. Anlyzation will be processed in the angular scattering intensity data so that the size of the particles responsible for creating the scattering pattern can be calculated.
The Matrix is a sci-fi action film about a computer hacker named Neo that has been brought into another world deemed “the matrix.” The Matrix is a prime example of cinematography. The film uses many different types of cinematography such as mise-en-scene, special effects, and camera shots to make it interesting and entertaining to the audience guiding their attention to the important aspects of the film.
Kozier, B., Erb, G., Berman, A., Burke, K., Bouchal, D. and Hirst, S. (2010). Fundamentals of
T. Mitchell, Generative and Discriminative Classifiers: Naive Bayes and Logistic Regression. Draft Version, 2005 download