Introduction

To understand this case study, prerequisites in geometrical optics and photometric are needed.

____________________________________________________________________

This case study tackles the choice of an image sensor to image a patch of agarose gel with immobilized luminescent bacteria. The patches are small squares with a surface of . The type of sensor used will be CCD, with an objective whose focal length is f' = 18 mm, whose transmission is Topt = 0.9 and whose apertures are N = {2.8 ;4 ;5.6 ;8 ;11.3 ;16 ;22.6 ;32}.

The bacteria's luminescence is wide band around  = 500, but the wavelength peak will be taken into account for these measurements. The luminance was measured by spectrophotometry to be L0 = 1x10-4 W.sr-1.m-2.

There are three sensors to chose from. Their technical data, coming from the manufacturing data, are indicated in table 1.