Smoothing the intensities Intensity Smoothing More Smoothing
Intensity Derivative Smoothed Intensity First Derivative Second Derivative
The Derivative of a Convolution
Analyzing a 2D image Image after smoothing and second derivative Image Black = Negative White = Positive Zero-Crossings
Smoothing a 2D Image To smooth an image, I(x,y), we can convolve with a 2D Gaussian:
Differentiation in 2D To differentiate the smoothed 2D image, we will use the Laplacian operator: We can again combine the smoothing and derivative operations: (displayed with sign reversed)
Detecting intensity changes at multiple scales
Computing the contrast of intensity changes
The Eye
The Neuron Major parts of a neuron: Cell body Axon Terminal Synaptic cleft Dendrites
Projection from the Retina
Retinal Ganglion Cells Retinal Ganglion cells have receptive fields that exhibit a center-surround structure.