Week 8: 16/11/2012

This week in the lecture we discussed light and how it moves in the air.

What is light?

Light is a form of energy detected by the human eye, unlike sound, it does not require a medium to propagate. It can travel from the Sun through the vacuum of outer space to reach Earth.

Light is a transverse wave. [Traverse Wave - is like a rippling pond in which the water molecules move away from the disturbance.]

We also discussed light waves and the rage visible to humans. Below is a slide explaining this.

Below is the electromagnetic Spectrum:

We also discussed the velocity of light and how it changes when it passes through air or glass. In air light travels about one million times faster that the speed of sound(33 m/s).

We also briefly discussed the frequency and wavelength of a lightwave but we have already discussed this in week 2.

Also we talked about the visible light spectrum and how light bends when passed  through a prism, this is due to the density bending them.

We also discussed it affects on the environment such as reflection. I will be review these more at a later date.

In the Lab we took an image of a church tower and edited it using Photoshop.

We applied a default filter to the image and it cause it to get lighter and have white pixel areas on it.
We then applied preset masks and they did the following:

High Pass - made the image become grayer.
Maximum - made the image go lighter and blurry.
Minimum - made the image go darker and blurry.

I then created a custom filter that had all zeros except the center value, which was one, this cause nothing to happen to the image. This happens because when the filter is added to the pixel it doesn't change the value enough for us to notice a change.

I then created create a new filter with a two by two matrix of one’s at its center, this made the picture do so much bright the picture is nearly all white.

I then create a new filter with a two by two matrix with +one’s on one diagonal and –one’s on the other, this made the picture go almost entirely black, only some faint white outlines are left.