Fig. 4.

Example images of individual thin-smear blood cells under different forms of illumination. Top two rows are negative examples of cells that do not include a malaria parasite, bottom two rows are positive examples that contain the parasite. Example illuminations include from (a) just the center LED, (b) uniform light from all LEDs, (c) all LEDs with uniformly random brightnesses, (d) a phase contrast-type (PC) arrangement, (e) an off-axis LED, (f) a phase contrast (PC) ring, (g) optimized pattern with red illumination, (h) optimized multispectral pattern, and (i) the same as in (h) but showing response to each individual LED color in pseudo-color, to highlight color illumination’s effect at different locations across the sample.