In order to validate and to optimize the imaging capabilities of a micro-lens-array (MLA) based optical detector dedicated for preclinical in-vivo small animal imaging applications a numeric investigation framework is developed. The framework is laid-out to study the following MLA detector parameters: micro-lens diameter (D) and focal length (f), as well as sensor pixel size (A). Two mathematical models are implemented for light modeling: line-based and cone-based ray projections. Since the MLA detector requires mathematical postprocessing, specifically inverse mapping for image formation, the framework is fully integrated into such approach. MLA detector designs have been studied within valid parameter ranges yielding sub-millimeter spatial resolution for in vivo imaging of mice for detector-object-distances (t) up to 50 mm. In summary, there is a non-linear dependency of the detector's spatial resolution, scaling with D and f, for any respective t. On the other hand, detector efficiency is strongly dependent on f. Regardless of mathematical postprocessing the following set of intrinsic detector parameters had been found optimal for the intended application: D = 0.336 mm, f = 4.0 mm, A = 0.048 mm.
When mathematical postprocessing is involved, particularly three-dimensional surface recognition, increasing f (cf. decreasing D) yields solid angles of the incoming rays closer to 90° and, thus, will decrease spatial depth information from the elementary images. Hence, a setup with D not larger than 0.5 mm and f between 2.0 mm and 3.0 mm is recommended.