Delta

I used to be involved in designing cameras. When you transmit video to a digital TV or over the internet, you don't transmit every frame in full. Instead, you transmit occasional frames in full, then send the differences, or deltas. This works because most of the time in TV/video conferences the background stays the same and just the people move, so transmitting the deltas takes much less bandwidth. Also the eye is much more sensitive to movement than detail or colour.

What am I whittering on about? When looking for a blip, I am surrounded by many of the same things day in, day out. I don't think I've ever noticed this doorway before, but because it was different today it caught my eye - so today I I guess I blipped the delta. The thing that had changed since I last went past.

A mattress in a doorway as someone moves house. I guess things are changing for the owner too...