a stage, adapted for holding the sample to be tested;

a light source module, configured to output a detection light to the sample to be tested on the stage and reflect a reflected light, wherein the detection light comprises a spectrum of a first light and a spectrum of a second light, the first light and the second light have two different peak wavelengths, the spectrum of the first light is adapted for detecting one of the two detection features, the spectrum of the second light is adapted for detecting other one of the two detection features, a luminous intensity of the first light and a luminous intensity of the second light are independently controlled, the reflected light comprises an image frame, and the image frame displays the two detection features; and

an image sensor, disposed on a path of the reflected light and adapted for receiving the image frame.