Anechoic chambers

Anechoic Chambers are a really weird thing. They're basically a place where as a person you can't hear a thing. They have noise values of -dB (which took me a bit to get my head round but it's like -centigrade it is actually a "positive" number it's just below our scale) so are totally silent to humans, which can apparently drive people completely insane and they start hallucinating. They're also fairly radioactive, basically you don't wanna be in one.

In terms of scientific use they're mostly used for measurements of waves. They don't let any waves out, not just sound waves. It's due to the lack of interference which I can imagine is useful for scientific accuracy. Apparently also useful for testing stuff like antennae or radar, which makes sense too. They come in many shapes and sizes (tiny box to aircraft hanger) and are also meant to be a fire hazard. When it comes to using an anechoic chamber equipment is usually made of wood or plastic and not metal so as to reduce reflection.

In summary an anechoic chamber is a room in which sound is completely absorbed instead of reflected, they come in many sizes and are a huge fire hazard. It's not a place you want to put people but they're great for scientific experiments regarding waves due to the lack of interference.

Image Lab!

Back again, same format. This Lab is about images though which made a pretty cool change. It was quite straight forward though. 

Manipulating Images Using Arithmetic

Image filtering, enhancement and general manipulation using GIMP

1) Download the image file CH_Tor.jpg from Moodle.

Done.

2) Find and run GIMP.

Yay, freeware! 

3) Use File > Open... to load and display CH_Tor.jpg.

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4) Explore some of the filters (and their options) in the Filters menu (particularly the range of Blur and Enhance filters).

This is gaussian blur. It looks like a kinda mild blur I guess? I know Gauss did a lot of work with magnets and such, possibly related? 

Censorship and PC gone mad! 

5) Suggest possible uses for some of these filters for processing digital photographs.

No idea what you could use the former for? Maybe if you wanted to take something out of focus. The latter is used for censorship though, obviously. 

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6) Select Filters > Generic > Convolution Matrix...

7) Click the Reset button to reset the matrix to its default (with only a 1 in the centre cell of the matrix) then click OK. What does this filter do and why?

No idea what it did. Doesn't look like anything noticeable? 

8) Create a new filter with a three by three matrix of 1’s at its centre. Also tick the Normalise box. What does this filter do and why?

It looks kind of.... stretched? Disproportionate certainly. Not sure what's going on honestly. 

9) Create a new filter with a three by three matrix with +1’s on one diagonal and –1’s on the other. Like this:

1 0 -1

0 1 0

-1 0 1

What does this filter do and why?

Now it looks a little bit blurred. I still have no idea what this filter actually does though! It remains a mystery to me. :) 

Fairly straightforward lab though.