Fig. 1. Ringing effect

Fig. 2. Schematic diagram of bilateral filter

Fig. 3. Schematic of gray scale chart

Fig. 4. Pixel distribution in low illumination images

Fig. 5. The construction of image pyramid

Fig. 6. Schematic of low illumination denoising

Fig. 7. Car image with noise

Fig. 8. Car image denoised with Daubechies wavelet

Fig. 9. Car image denoised with the proposed method

Fig. 10. SNR value before denoising

Fig. 11. SNR value after denoising