How to calculate brightness of an image

1. How is image brightness calculated?
2. How do you measure brightness of color?
3. How do you find the brightness of a grayscale image?

How is image brightness calculated?

call it maxval. Estimate your sharpness/brightness index as - (maxval * average V channel values) / (average of the hist values from 0th channel), as said above. This would give you certain values. low bright images are usually below 30.

How do you measure brightness of color?

A photometer measures the brightness (luminance) of visible light as it is perceived by the human eye. Colorimetry is the science of measuring color (chromaticity) as it is perceived by the human eye. Some instruments, such as a spot meter, can measure both luminance and chromaticity.

How do you find the brightness of a grayscale image?

Here's one method for relative luminance (Y): Y = (0.2126 * R) + (0.7152 * G) + (0.0722 * B) Here's another: Y = (0.299 * R) + (0.587 * G) + (0.114 * B)