Category Archives: tech

Rate-Distortion Graph

I’ve invested a bit of time in getting some nice rate-distortion graphs out of my wavelet image compression library. Now that it’s embedded, the process is fairly easy: Compress once into a single file and then decompress only enough bits … Continue reading

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Patenting CPU instruction sets and $150 PCs

Via a blurb on ArsTechnica about a Chinese $150 PC, I’ve stumbled upon the Story of Lexra, a now out-of-business semiconductor IP provider. A few things in that article struck me as interesting, namely You cannot patent an instruction set. … Continue reading

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Size-optimising Code

I try to keep my image compression code fairly simple; it doesn’t do the best lossy compression, it doesn’t to the best lossless compression, but it does both fairly well, fairly fast, and without introducing much code bloat. As a … Continue reading

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Wavelet 3.2

As I’ve taken a two-day vacation pre-easter, I’ve gotten some more work done on my Wavelet Image Compression Library (and not played games as some of my colleagues were led to believe ). Before this version all the subbands of … Continue reading

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Cocoa and Objective C

I am currently writing a graphical user interface (GUI) for my Wavelet Image Compression Library that will allow for selecting and inspecting compression settings. As my “main computer” for the past year has pretty much been an Apple Mac mini … Continue reading

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Wavelet 3.1

Another week, another release of my Wavelet image compression. I figured out how to do complete embedding, which justifies another release. This means you can compress an image once, and then get different rates by simply truncating that file! The … Continue reading

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Wavelet 3.0

I’ve been steadily working on my wavelet image compression for the past few weeks, and in the process have improved it in many ways. These are largely not technical improvements, but rather a huge code refactoring, the creation of decent … Continue reading

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Hilbert Curve

I’ve been reading a bit about the spacefilling curves for my wavelet image compression (take a look here and here). There is a very nice way to convert from the Hilbert derived key to (multi-dimensional coordinates) described by John J. … Continue reading

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Revision Control Systems

I’ve been looking for something (other than regular backups) to keep a history of my personal development projects. Once upon a time, I used Perforce (the free 2 client license), but I’ve never really gotten on with it that well; … Continue reading

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Automated Downloading

On Patrick‘s insistent encouragement, I’ve finished my “downloading system”. I use it to easily and quickly queue files on a remote machine for downloading (or starting (Bit-)torrent downloads). It consists of two scripts, one written in PHP and running on … Continue reading

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Compute your own PS3 Cell Yield!

Here is a little Python script, that I wrote to compute yields for the PS3′s Cell chip on a 300mm wafer with different defect rates, depending on the number of SPEs required to be intact…

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Apple’s “Mighty Mouse”

There is a lot of confusion about Apple’s new Mighty Mouse (which IMO is a crap name). As I’ve got mine today, I thought I’d dispel some of it: It still has a physical micro-switch that is activated when applying … Continue reading

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