- [Narrator] Our brains do a lot of thinking and calculating
before information and understanding reaches consciousness.
So much happens before we're consciously aware of it,
it defies the analysis of modern science.
You can recognize faces you've seen before
for only a fraction of a second.
Or, quickly learn to forget to detect harmless smells,
as any owner of a smelly pet will confirm.
Everything we see and hear is pre-interpreted by the brain.
Our hearing detects very subtle variations
in frequency, amplitude, and phase,
and amazingly complex pattern recognition is applied
in a tiny fraction of a second for us to understand,
not just here, what's happening around us.
When we see, the neurons in the back of our eyes
break images down into the separate kinds information,
including color, brightness,
and various kinds of shapes and angles
before the information is sent to the visual cortex.
Of course, if we're looking at video footage,
the light takes a huge journey.
Let's imagine an exterior shot of an object or a person.
The sun produces light, which reaches
the Earth in about eight minutes.
This light bounces off our subject,
and some of it goes through a filter over a camera lens,
through the lens onto a sensor that
counts the number of photons
in different areas of the picture.
This photon count is converted into binary,
and there's more on this in the lesson about binary.
It's often then converted into a color system,
so the information can be stored, usually as a smaller file,
using compression, and again, more on this
in the lesson about video compression.
That file is then later decompressed to be viewed.
The information travels through a graphics processor,
and via the CPU and memory on a computer,
it gets displayed on a screen.
And the light emitted from the screen reaches your eyes,
which perform exactly the same analysis
as they would if they saw the subject in person.
It's quite a journey, but the principals of
light, shadow, form, and composition, are relatively simple.
They haven't changed since the origins of cave painting,
and before, because the way our vision works,
hasn't changed either.