Categories
Coding

Issues to POST streamed data to a webservice

Recently I had quite some issues with sending data via POST to a webservice from an Android app.

Categories
Thesis

FPU Boost

I'm kind of thrilled right now.

I just updated JavaCV to the latest version (2011-07-05) which includes OpenCV 2.3.0 and some precompiled code for Android devices with an FPU (armeabi-v7a). Just by replacing JavaCV I gained an enormously computation boost. Well, of course I knew that an FPU is better for heavy number crunching than a CPU. Nevertheless I'm surprised that this makes such a big difference even in the tiny smartphone (HTC Desire HD).

My current implementation detects Shi-Thomasi corners and then tries to track them in following video frames. Where yesterday (without "FPU-code") my detector needed around 3 to 4 seconds to detect about 50 corners (even though it didn't much matter if I detected 50 or let's say 250) now it needs about 170 milliseconds and very often even less. My tracker needed about 1000 milliseconds to find known corners in new frames -- now 20 milliseconds. The detector is about 18 times faster.

I know, I know ... this is kind of supposed to be like that 😉 . But I'm just surprised to see this working. As result from that I will just target on devices with an FPU. I'm not quite sure yet if a certain Android version requires an FPU, so could just say e.g. from 2.3.0 and up my program will work or if I need to actually check this during runtime.

Categories
Thesis

javacv

JavaCV is a wrapper for a couple of libraries, including OpenCV. They also provide a pre-compiled OpenCV for Android. Looks promising. Will take a look at it. Wonder if this slows down the application somehow, because they are some more method calls because of the wrapper stuff I guess. But if it speeds up the development process I could live with that for now.

Categories
Thesis

jopensurf - Java implementation of opensurf

jopensurf - Java implementation of opensurf - Google Project Hosting.