Posted in digital video processing on October 23, 2009 | Leave a Comment »
The following animation shows an intriguing property of motion perception: there exist two attractors (clock-wise and anti-clockwise) in this dynamic system.
Folktales tell you whether you see it clockwise or anticlockwise will determine whether your left brain or right brain is dominating. What is more interesting to me is how can we have two stable interpretation [...]
Posted in ee565 on October 23, 2009 | Leave a Comment »
This week ,we have discussed wavelet thresholding – an extremely simple operation but has shown effective in image denoising applications. Given the fact that thresholding is among the simplest nonlinear operators, there is a lot we can say about the role of nonlinearity in image processing.
What is wrong with linear models? Linear combination of Gaussian [...]
Posted in ee565 on October 23, 2009 | Leave a Comment »
In the class, I mentioned Translation Invariance (TI) is a difficult concept in image processing. To understand TI, you need to understand down-sampling first; to understand down-sampling, we need to talk about sampling theorem or Analog-Digital conversion. Nyquist-Shannon sampling theorem states the condition for perfect reconstruction of band-limited signals from their discrete samples. The interpolation [...]
Posted in ee565 on October 23, 2009 | Leave a Comment »
Convexity is a concept you don’t see in image processing textbooks. It is a little advanced mathematical tool for engineering students. In the mathematical literature, you can refer to Rockafeller’s “Convex Analysis” (comprehensive and deep) and Boyd&Vandenberghe’s “Convex Optimization (online available at http://www.stanford.edu/~boyd/cvxbook/). In the literature of signal processing, Youla’s 1978 paper was likely the [...]
Posted in ee565 on October 8, 2009 | Leave a Comment »
In this week’s computer assignment, many of you faced the obstacle of It turns out only few students with biometrics background knows how to calculate this Receiver-Operational-Curve thing. You might feel disappointed since I never even mentioned the ROC in the class – “how am I supposed to work this out? it is not covered [...]
Posted in ee565 on October 8, 2009 | Leave a Comment »
This year’s Nobel Prize in Physics was unexpectedly awarded to three engineers: one is the “father of fiber optics” Charles Kao (a Shanghaiese who was the Chancellor of CUHK) and the other two are inventors of CCD sensors. In the history of Nobel prize, last time engineers got lucky when two Bell Lab engineers accidentally [...]
Posted in ee565 on September 24, 2009 | Leave a Comment »
Based on my interaction with some of you, mathematics and programming skills are likely to be two deciding factors in your success of doing research in various fields (e.g., image processing, biometrics, communication, networking etc.). Therefore, it is inevitable to feel the frustration over some difficult papers (involving deep mathematics) or challenging projects (involving a [...]
Posted in ee565 on September 24, 2009 | Leave a Comment »
I understand some of you might be upset about losing some point in CA#2. Now here is the bright side: if you look at the grading system, an A grade is 90/100 – so there is a comfort zone where you can lose as many as 10 points. In fact, usually I also give out [...]
Posted in ee565 on September 17, 2009 | Leave a Comment »
Due to time constraint, we will have to say farewell to the topic of autoregressive(AR) model and move to a new chapter today. However, there are still many interesting stuff related to AR you can dig into:
1) Usefulness of AR. As I mentioned in the class, AR model is more successful on speech than image [...]
Posted in ee565 on September 14, 2009 | Leave a Comment »
I was kept busy during the office hours today and glad to see many of you have put significant effort into the first computer assignment. Well, like I said in one of my emails, this assignment might appear easy from a coding (programming) perspective; but there are a lot more that you can learn than [...]
