Resolution of human eye

Optical Resolution
An imaging system maybe an individual component including the lens, recording and display components. Each of these components results in the optical resolution of a system, as well as the environment.

Resolution of Human Eye
The resolution of an image is the smallest detail of the image.The resolution is determined using :-
 * Wavelength method: resolution = wavelength of the signal used
 * Pulse length method: resolution = half pulse length = pulse duration x speed of pulse/2

The human eye is a limiting factor of many systems, when the aim of the system is to present data for the humans for processing. The best visual acuity of the human eye is at its optical center which is called the fovea, which is less than 1 arc minute per line pair, reducing rapidly away from the fovea. The human brain requires more than just a line pair to understand what the eye is imaging. Visual acuity is defined as 1/a, where a is response in x/arc-minute, where x is the line pair. So when we define x to be a line pair, the 1/a value is 1.7 under good lighting conditions.The acuity of 1.7 when light level is greater than 0.1 Lambert. A Lambert is a unit of luminance to 1/pi candela per square centimeter. The eye moves rapidly in a small angular amounts and continually update the image in one's brain to paint the detail. We also have two eyes and our brain to combine the signals to increase the resolution, we also move our eyes around the scene to gather more information. Because of these factors, a higher resolution image than possible with the number of photo receptors in the retina. If we consider a view in front of you that is 90 degrees by 90 degrees, like looking through an open window at a scene. The number of pixels would be :- 90 degrees * 60 arc-minutes/degree * 1/0.3 * 90 * 60 * 1/0.3 = 324,000,000 pixels (324 megapixels). At any one moment, you actually do not receive that many pixels, but your eye moves around the scene to see all the detail you want. But the human eye really sees a larger field of view, close to 180 degrees. Let's be conservative and use 120 degrees for the field of view. Then we would see 120 * 120 * 60 * 60 / (0.3 * 0.3) = 576 megapixels. The full angle of human vision would require even more megapixels. This kind of image detail requires A large format camera to record.