So let's talk a bit about how images are formed.
So we're going to look at the most basic example of an image formation onto a piece of film.
So imagine you're outside in a park and you're holding a strip of film while facing a tree so light
reflects off the tree at different points and bounces off a tree onto your piece of film.
So as you can see in this example what happens here is at the top of the tree and the middle of the
tree are going to reflect at similar points along the farm.
That's not good.
That will actually focus that will basically result in an unfocused image or blurred image here.
So as we can see that's not how our eyes or cameras work.
This is a best example of how our eyes and cameras work.
We essentially use a barrier to block off most points of light while leaving a small gap here and that
gap has called aperture.
And this allows us some points of light to be reflected onto the form.
So this gives you a much more focused image and that's actually the basis of a pinhole camera.
So it is a problem with a simple pinhole camera model in that the aperture is always fixed.
So that means that a constant amount of light is always entering this will which can be sometimes overpowering
for the film.
Meaning that everything is going to look white.
And secondly we can focus using this fix up issue to focus the image even better although it's never
going to be as bad as the previous image.
We still need to move the film back and forth.
And that's not really a good system.
So how do we fix this.
Well by using a lens and an adaptive lens which is what most modern cameras and our eyes use it allows
us to control the aperture size and in photography aperture size is referred to as f stops and cameras
and lowa is better and also allows us to get some nice depth of field which is also called booka in
photography.
Just so you know book Booker is a highly desirable trait in photography.
It allows us to have very blurred backgrounds while we focus on a growing image resulting in a pretty
nice effect.
Secondly with using a lens you actually can control the lens wit which allows us to instead of moving
the film back and forth.
We actually use a lens to focus directly on this point here.
This results in a very nice nicely controlled system so fiercely before discussing how computers two
images.
I think it's good to discuss how humans see images and it is one thing you shouldn't know humans are
exceptionally good at Image Processing starting with our eyes they're remarkably good at focusing quickly
seeing in varying light conditions and picking up sharp details and then in terms of to putting what
we see humans are exceptional at this as we can quickly understand the context of different images and
quickly identify objects faeces you name it we can actually do this far better than any computer vision
technique right now.
And our brain our brains do this by using six layers of visual processing that you can see here.
I won't go into the details of this but it's incredibly complicated.
And if you're curious you can visit the Wikipedia page on our visual system right here.