00:03
So we're given a three by three plus sign picture where each block on that three by three grid is a color.
00:15
White is zero, light gray is one, dark gray is two, and black is three.
00:20
Those are maybe you might say the intensity or something.
00:22
And our first task is to make a matrix that represents those colors for that plus sign picture.
00:29
So in the upper left hand corner we have light gray, so that's a one.
00:33
Right next to it we have black, so that's a three.
00:37
And next to that, we have another light gray.
00:39
That's the one.
00:40
In the second row, it's all black, so we're going to have three, three, and three.
00:46
And then in the bottom row, we have, again, light gray, then black, and light gray.
00:52
So there's our matrix representing that plus sign.
00:56
Now our next task is to take that and using matrix addition, create a, a, a contrast changed matrix.
01:08
So our new contrast is going to have black become gray.
01:12
So everywhere we have a three, we want it to become, let's see, i think we want it dark gray.
01:21
We have black to become dark gray.
01:22
So the threes have to become twos.
01:25
And we want light gray to become white.
01:27
So we want the ones to become zero.
01:29
So in this case, basically, we want each pixel to be one color lighter.
01:34
So if we add a matrix of all negative ones, we will end up with everything shifted.
01:43
So we'll have this big three by three matrix of negative ones, and then we can add them together to get our resultant contrast adjusted matrix.
01:54
So one minus one is zero.
01:57
Three minus one is two...