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。
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First, after the foreground is retrieved, the luminance test is used to reduce part the object region that has higher pixel's intensity in the foreground than the corresponding background.