The Plustek 8100 is a relatively cheap but good quality film scanner. It produces much nicer scans than most flatbed-type scanners, but it can only capture small format film. In this page I show how to modify a Plustek 8100 to scan medium format (120 film) by stitching together multiple …
A Class of Multivariate Functions that Behave Like Single-Letter Random Variables
Vector-encoders of a certain pretty restricted class happen to carry the same information content as univariate encoders. This turns out to be relevant to an aspect of time-expanded information bottlenecks.
Claim
Take X _ 1,\dots, X _ n iid over finite alphabet …
Extracting Relevant Information over Many Trials
The information bottleneck scenario goes like this:
We are interested in a quantity Y but only observe X which we must process down to a rate R \in (0, H(X)). To this end, what random variables (U,Q) minimize H …
Hypersphere Cap Volumes in Matlab
The volume of a height-h cap of a ball of radius r in dimension n can be derived:
\begin{equation} \operatorname{vol}(\operatorname{cap}) = \frac{1}{2} \cdot \frac{\pi^{n/2}}{\Gamma\left(1+n/2\right)} \cdot r^n \cdot I_{(2rh-h^2)/r …On Suboptimality of the Berger-Tung Bounds
The Berger-Tung inner and outer bounds give a approximation to the rate-distortion region in lossy distributed source coding. The regions are not tight in general. Their tightness is discussed throughout Chapter 12 of Network Information Theory by El Gamal and Kim (in particular Section 12.5), but even so I …