X1011690301-00028-07421</DOCNO> Psychology 221A: Sensory and Physiological Psychology Week 2: Light and Eye OUTLINE: Light Optics and Lenses The Eye: Gross Morphology and Function The Lens and Accommodation Retina: Photoreceptors (cones, rods, fovea, phototransduction) Photoreceptor Signals Spectral Tuning of Photoreceptors (more in Week 6) IF THERE'S TIME: More on Optics: SF, Contrast, MTF (more in week 4) Nyquist, cone mosaic, aliasing LIGHT VISIBLE OBJECTS: - self-luminous (the sun) - reflect light ELECTROMAGNETIC ENERGY SPECTRUM - 400 nm - 700 nm = Visible Light Particle / Wave Theory of Light (combined): Photons (or quanta ) are particles of energy emitted from atoms, that travel through space as a wave l = nanometers/cycle, - photons (light) travel in a straight line - l = c/ n , l = wavelength (nm/cycle) n = frequency (cycles/sec) c = speed of travel of the wave (nm/sec) - speed of light is a function of the medium (186,000 miles/sec in a vacuum) - Energy (of a photon) = h n -> " radiant energy" physical measure of light = radiance psychophysical measure of light = luminance OPTICS (study because it s related to the EYE): - Reflection : Mirror -> angle of incidence = angle of reflection - Refraction : light can be bent when passing from one medium to another e.g., water, glass (thick/thin), prism (chromatic aberration) e.g., Lens : produces an image of an object at some distance away from the object (convex or concave) OPTICS OF A LENS -
(Photoreceptor Signals Spectral; Tuning more; T:in Week 6) (light; can be; bent; T:when passing from one medium to another) (it; related; to the EYE) (SF; Contrast; ) (energy; emitted; from atoms) (l = wavelength (nm/cycle) n = frequency; is; a function of the medium (186,000 miles/sec in a vacuum)
Photoreceptor Signals Spectral light it SF energy l = wavelength (nm/cycle) n = frequency
Tuning more can be related Contrast emitted is
T:in Week 6
bent T:when passing from one medium to another
to the EYE
from atoms
a function of the medium (186,000 miles/sec in a vacuum