luminance

Examples of luminance in the following topics:

• Perceiving Motion

  • Motion is perceived when two different retinal pathways, which rely on specific features and luminance, converge together.
  • First-order motion perception occurs through specialized neurons located in the retina, which track motion through luminance.
  • The motion-sensing neurons detect a change in luminance at one point on the retina and correlate it with a change in luminance at a neighboring point on the retina after a short delay.
  • The phi phenomenon is an illusion involving a regular sequence of luminous impulses.
  • Due to first-order motion perception, the luminous impulses are seen as a continual movement.

• Color Vision

  • The intensity, or luminance Y, can be found from the following equation:
  • The sensitivity to luminance drops off at low spatial frequencies, showing that we are not very good at estimating absolute luminance levels as long as they do not change with time - the luminance sensitivity to temporal fluctuations (flicker) does not fall off at low spatial frequencies.
  • The maximum chrominance sensitivity is much lower than the maximum luminance sensitivity with blue-yellow (U) sensitivity being about half of red-green (V) sensitivity and about 16 of the maximum luminance sensitivity.
  • The chrominance sensitivities fall off above 1 cycle / degree, requiring a much lower spatial bandwidth than luminance.
  • This graph shows the sensitivity of the eye to luminance (Y) and chrominance (U, V) components of images.

• Other Forms of Energy

  • Thermal, chemical, electric, radiant, nuclear, magnetic, elastic, sound, mechanical, luminous, and mass are forms that energy can exist in.
  • Luminous Energy: This is energy that can be seen because it is visible light.
  • An example of luminous energy is light from a flashlight.
  • For example, luminous energy is radiant energy.

• Light

  • Wave amplitude is perceived as luminous intensity or brightness.
  • The standard unit of intensity of light is the candela, which is approximately the luminous intensity of one common candle.

• Testes Ducts

  • The ciliated cells serve to stir the luminal fluids, and this may function to help ensure homogeneous absorption of water from the fluid produced by the testis.
  • This results in an increase in the concentration of luminal sperm.

• Standard Units (SI Units)

  • It should be apparent that the move into modern times has greatly refined the conditions of measurement for each basic unit in the SI system, making the measurement of, for example, the luminous intensity of a light source a standard measurement in every laboratory in the world.
  • Now, with the prevalence of incandescent and fluorescent light sources, the candela is defined as the luminous intensity in a given direction of a source that emits monochromatic radiation of frequency $540 \cdot 10^{12}$ Hertz and that has a radiant intensity in that direction of 1/683 watts per steradian.

• Spherical and Plane Waves

  • In 1678, he proposed that every point that a luminous disturbance touches becomes itself a source of a spherical wave; the sum of these secondary waves determines the form of the wave at any subsequent time.

• Dimensional Analysis

• Problems

  • An optically thin cloud surrounding a luminous object is estimate to be 1 pc in radius and to consist of ionized plasma.Assume that electron scattering is the only important extinction mechanism and that the luminous object emits unpolarized radiation.

• Tubular Reabsorption

  • These processes involve the substance passing though the luminal barrier and the basolateral membrane, two plasma membranes of the kidney epithelial cells, and into the peri-tubular capillaries on the other side.