The number of photons collected by a pixel, and therefore the pixel value, is a measure of the flux, and thus of the brightness of the light source.
一个像素所收集到的光量子数，也就是像素值，是测量的光通量的方式，即反映了光源的亮度。
2
Photometers are specifically designed to measure emitted, reflected or transmitted light in photometric terms of luminous flux, luminance, illuminance or luminous intensity.
光度计是专门用于测量发射，反射或透射光的光通量，亮度，照度或发光强度等。
3
The measurement of the luminous fluxof UHP (Ultra High Power) light source is described in this paper.