Table of Contents
Advertisement
Histogram
The histogram is a great tool that helps you to improve the overall exposure of the image.
Y
The Y or luminosity histogram is a graph that describes the human-eye perceived brightness
distribution within an image.
To produce the luminosity histogram, first break an image into individual pixels, then each pixel is
converted so that it becomes a luminosity based on a weighted average of the three colors at that
pixel. The green, red, and blue channels account for 59%, 30% and 11% of the perceived luminosity
respectively. This is because human eye is more sensitive to green light than it is to blue or red light.
Finally the luminosity histogram is produced by counting how many pixels are at each brightness
level as shown in the diagram below.
25
Advertisement
Table of Contents
