Figure P52

that 0m2 = 1.5° and the minimum useful intensity contrast is Cie = 0.01. Plot the minimum 8x vs. A to give Cie = 0.01. Consider A from 0.15° to 15°. (Note: When A is large, only a small 8x is required; as A decreases, Sx becomes larger until finally 8x = A/2 to get Cie = 0.01.)

5.3. A certain photoreceptor subject to general illumination has an output depolarization, vm, which is log-linear over the range, {I1, I2}. See Figure P5.3. In this range, vm can be modeled by vm = A ln(I/B), A > 0

Assume I .lies in the range, {I1, I2}. Consider a small increase in intensity, AI, above I.

a. Find an algebraic expression for the contrast in vm, defined as Cvm = Avm/ Vm Note that the approximation, ln(1 + x) Y x, x < 1, can be used.

b. Find an expression for Cvm/Q in the range {I1, I2}. _Is it possible for Cvm/Cj to be > 1? What are the conditions? (Q = AI/I).

5.4. An array of three one-dimensional photoreceptors are connected as shown in Figure P5.4: The visual object is an infinite, {0, Io}, spatial square wave with period, A. The receptor center axes are spaced ±b around the x = 0 axis. Each receptor has a Gaussian DSF with half-angle, 0m/2. Thus,

Was this article helpful?

0 0
Peripheral Neuropathy Natural Treatment Options

Peripheral Neuropathy Natural Treatment Options

This guide will help millions of people understand this condition so that they can take control of their lives and make informed decisions. The ebook covers information on a vast number of different types of neuropathy. In addition, it will be a useful resource for their families, caregivers, and health care providers.

Get My Free Ebook


Post a comment