Fig. 4.

a) Image captured with the endomicroscopic probe of a uniform chrome grid with a period of 32 μm placed in front of a homogeneously fluorescent target illuminated in epi-direction. A highly resolving image quality is obtained. Slight pincushion distortion effects are visible and progressively increase towards the edge of the field of view. b) Radial intensity profile obtained within the red rectangle in (a) indicates precise edge response functions as a function of the radial distance from the optical axis. c) The first derivative of the edge response function (b) shows the line spread function. Its full-width-at-half-maximum is a measure for the resolution of the device. Averaged FWHM of 0.74±0.08 μm has been obtained.