Week 5 Flashcards
Marr's 3 Levels, Vision
What is vision for?
To perceive information about things and organisms around us to do what we need
How doe your brain infer color?
It considers the object color in context to the illuminant colors to infer
Why can’t we understood how vision works by just studying the biology?
Cog sci situates the biological information by applying it to broader workings of the human system and world
What’s Marr’s 3 levels of analysis?
The computational level, algorithmic/representational level, and implementational level
What is the computational level?
The goal of the system
What is the algorithmic/representational level?
The representation of the input, representation of the output, and computational steps used in between
What is the implementational level?
What physical systems and components are involved in the execution of the computation?
What is the computational task of vision?
Taking the 2D visual input we receiving and perceiving the 3D nature of the world
What is the computational process of vision?
Input: light stimulating photoreceptors
Computation: constructing workable representation of what’s in the world
Output: identify an object and interact with it
How do computers create vision/outlines versus humans?
Computers use a grid on 0s and 1s to identify lightness and darkness, humans have 126 million photoreceptors to create light patterns
How does vision work for humans in Marr’s 3 levels?
- Identify an object 2. Compute edges 3. Brain cells are connected in a way that carries out algorithm
What do photoreceptors represent?
Light intensity
What does the retinal ganglion cell do?
Encodes contrast (similar to binary, on or off system)
What do retinal cells do?
Perform the computations
What is a cell’s receptive field?
Describes what retinal simulation makes it fire
