1B50 – Cognitive Vision

Daniel J Hulme

Outline

• Cognitive Vision– Why do we want Computers to See?– Why can’t Computers See?– Introducing Percepts and Concepts

• Visual System– The Eye and Brain– Early Visual Processes– Edge Detection

• Percepts and Concepts– Late Visual Processes– Concepts

What is Cognitive Science?

• Cognitive science is usually defined as the scientific study either of mind or of intelligence

• Intelligence is the mental capacity to reason, plan, solve problems, think abstractly, comprehend ideas and language, and learn

Brains

• Early creatures had very simple wiring

• Then came more complicated wiring

cnidariansBraitenberg's Vehicles

Cambrian ExplosionFemale Copilia

Compound-eye Trilobite

So what?

• Why do we want computers that can see?

• It seems that the evolution of the eye was a catalyst for the rapid development of the brain.

• Practical applications

• Philosophical implications

Why can’t computers see?

• The humble Bumblebee• 850,000 vs 100 billion neurons • 3D navigation, colour vision,

memory, communication, learning capacity, etc

• The brain of a bumblebee is a massively parallel processor with computation and storage capacities far superior to the most powerful supercomputer ever designed

Bumblebee

Why can’t computers see? (2)

• Ambiguity: perceiving one form from a potentially infinite amount of possible forms

• “We shall discuss violence on TV.”VP

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Gestalt

Semantics of Perception

• We don’t actually see what is ‘out there’!

• Distal – the 3D thing ‘out there’

• Proximal – 2D pattern of stimulus on retina

Semantics of Perception (2)

• We are bombarded by stimulus

• Passive and selective filtering

• Create a ‘useful’ perception– Early visual processes to extract features– Use experience to construct the scene

• Ontogenetic and Phylogenetic

– Use concepts to rationalise and decision make

Dimples

Maths

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Questions