Fig. 1. Structure of the CMOS image sensor

Fig. 2. Image collected by the sensor under uniform illumination

Fig. 3. Gray curve of the image. (a) Gray mean value curve of the column; (b) gray curve of the pixels in the column

Fig. 4. Response curve of the image block

Fig. 5. Flow chart of our method

Fig. 6. Principle of the image acquisition system

Fig. 7. Image corrected by our method. (a) Original image; (b) corrected image

Fig. 8. Statistic result of the column gray variance. (a) Before correction; (b) after correction

Fig. 9. Correction results of different window widths. (a) Original image; (b) W=2; (c) W=4; (d) W=8; (e) W=16; (f) W=32

Fig. 10. Correction results of the Fig. 9(a) by different methods. (a) TPC method; (b) LSFOFC method; (c) our method

Fig. 11. PRNU of the image corrected by different methods