Fig. 1. Flow chart of spectral imaging based on pixel by pixel multiple-gain

Fig. 2. Probability curve of low gain readout of pixels affected by noise

Fig. 3. SNR curve of each spectrum segment

Fig. 4. Simulation image of pixel by pixel muli-gain spectral imaging

Fig. 5. Imaging simulation with 1~3σ random noise

Fig. 6. Lake texture features after adding 3σ random noise