PSYB51H3 Chapter Notes -Herman Snellen, Visual Acuity, Spatial Frequency
21 Sep 2015
School
Department
Course
Professor
Document Summary
Chapter 3: spatial vision from spots to stripes. Acuity: the smallest detail that can be resolved at 100% contrast. Visual angle: the angle subtended by an object at the retina. If the photoreceptors are spaced such that the whitest and blackest parts of the grating fall on separate cones, we should be able to make out the grating. But if the entire cycle falls on a single cone, we will see nothing but a grey field. Herman snellen defined visual acuity as the following: (distance at which a person can just identify the letters) (distance at which a person with normal vision can just identify the letters) Minimum visual acuity: minimum visual acuity refers to the smallest object that one can detect. Minimum visual acuity is the ability to discern small changes in contrast, rather than spatial limit. Minimum resolvable acuity: minimum resolvable acuity refers to the smallest angular separation between neighboring objects that one can resolve.
