12.5.5 Histogram-Based Background
Correction
Another simple histogram-based approach is used for background estimation in
biological images of sparse objects, where the majority of the pixels are back-
ground pixels. This method is based on the assumption that the distribution of
the dominant noise source in the image is unbiased and unimodal (which holds
for Poisson noise) [24]. The background is estimated by fitting a parabola
through the maximum values in the histogram. The corrected image is computed
by subtracting the estimated background image from the recorded image.
12.5.6 Other Approaches for
Background Correction
Several other approaches for shading correction have been published. For
example, the variation of illumination intensity can be