Fig. 4.

Lesion contrast results for the low contrast lesion specimen subgroup whose members were all difficult to visualize in RGB color photographs taken with a standard digital camera. This group included adenomas ($n=6$) and adenocarcinomas ($n=4$). (Reflectance images were available only for the final five adenomas and three adenocarcinomas.) This plot specifies the mean Weber contrasts and standard deviations for each image type. Because $I_N>I_L$ in these images, lesion and normal intensities were interchanged in Eq. (1). Image F440 displays greatest contrast, and the increase is statistically significant ($T$-test, $p<0.05$) compared to all of the other image types.