Home About Us Laboratory Services Forensic Science Communications Back Issues January 2009 research Figure 7: Correlation of noise from c1 with 11...

Figure 7: Correlation of noise from c1 with 11 reference patterns

Figure 7: Correlation of noise from c1 with 11 reference patterns

orrelation of noise from c1 with 11 reference patterns

This figure depicts the correlation of pattern noise in images from camera c1 with 11 reference patterns. The correlation values with camera c1’s reference pattern are depicted using small blue hexagonal symbols. Correlations, rho, are displayed on the y-axis, while the index of the image being correlated is displayed on the x-axis. The pattern is depicted as a smattering of the symbols, which range from .10 on the y-axis and 1 on the x-axis to .025 on the y-axis and approximately 325 on the x-axis. The correlations with camera c1’s reference pattern are centered on approximately 0.1 for the first 200 images (1 through 200 on the x-axis) because these images were also used to generate the reference pattern. The remaining images, 201 through 325, have slightly lower correlations centered on approximately 0.075. But even these correlation values are still significantly greater than the correlation values with other camera reference patterns. The average classification accuracy is 99 percent. The images having the smallest correlation with camera c1’s reference pattern (such as approximately 110 on the x-axis) are those of the night sky or similarly dark scenes. Camera c1 is a Canon PowerShot SD200.