Home Photos Recent Events Notice Board Articles Our Projects Us

Techy Stuff

This is our Techy page - bits and bobs that I want to tell the world about and maybe interesting to a small minority and probably don't fit in their own place in the website.

It's divided into sections that may link to other pages.

 

Hamster and Drive Cams

 

The hamster and drive cams use a couple of cheap web cams, the best one for the hamster is a night cam bought on ebay for £5.29. It has some lights that come on when the light levels reduce.

These are linked to our media PC which runs a script to filter and upload the images. I tried various web cam applications but not that were free could correctly access multiple cams and be configured to upload the best image taken over a selected period of movement.

So abandoning any possible use of freebee software I wrote my own using Python with its image library and video capture extensions.

 

Any number of cameras can be added and individually configured.

The basic approach is that movement is detected by changes in colour and brightness of adjacently grabbed images. Once movement is detected this starts a movement sequence, the length of which is configurable based on max length and max time with no movement.

The first image of the sequence is used as a reference for choosing the best image within the sequence. Each image being compared with the reference and the most change detected being the one saved. In this way we get the largest object in view rather than the largest change which happens with other systems only comparing adjacent images. Thus this approach always gets, for example the complete car going past the window rather than a part of it.

I will add some pics to illustrate it if anyone is really interested.