Fig. 1. The structure of low-light imaging system

Fig. 2. The structure of low-light CMOS image sensor

Fig. 3. The diagram of sensor initialization and power-on sequence

Fig. 4. The flow chart of system online upgrade system

Fig. 5. The curves of GAMMA correction versus different parameters

Fig. 6. The images of low-light with illuminance of 0.1 lux(a) and 0.000 01 lux (b)

Fig. 7. Filter window

Fig. 8. Low-light images without processing and processed by 3×3,5×5,7×7 filter window

Fig. 9. The curves of correspondence between gray value before and after correction and gray correction value

Fig. 10. Low-light images of traditional median filter processing (a) and improved median filter processing (b)

Fig. 11. Low-light image test system

Fig. 12. Low-light camera placed on an optical rotating base

Fig. 13. Images collected by low-light night vision cameras under different illuminances with improved median filtering

Fig. 14. The relationship between resolution and environment illuminances

Fig. 15. Program A (a) with cable pull and program B with cable elimination (b)