Abstract:
The invention concerns a method and an apparatus for measuring and computing the Amplitude Point Spread Function (APSF). The invention may be advantageously used in the field of Digital Holographic Microscopy (DHM).
Abstract:
The invention concerns a method of and an apparatus for the measurement of the Amplitude Point Spread Function (APSF), of an Optical Imaging System (OIS), wherein the APSF is defined as the complex field distribution of the beam delivered by the OIS and originating from a point source. The apparatus comprising a) an illumination source; b) a point object, PO1 irradiated by said illumination source; c) an object beam coming from said point object, collected by the Optical imaging System and transmitted! to a Wavefront Sensing Device, WSD; and, d) a computer with processing means adapted to acquire the data from said WSD and adapted to compute the Amplitude Point Spread Function and derived parameters associated with the OIS. In a generic embodiment, the WSD is realized by means of a Mach-Zehnder interferometer providing a digital hologram to the processing means. The invention may be advantageously used in the field of Digital Holographic Microscopy (DHM).
Abstract:
A new way of mixing instrumental and digital means is described for the general field of wave front sensing. The present invention describes the use, the definition and the utility of digital operators, called digital wave front operators (DWFO) or digital lenses (DL) , specifically designed for the digital processing of wave fronts defined in amplitude and phase. DMFO are of particular interest for correcting undesired wave front deformations induced by instrumental defects or experimental errors . DWFO may be defined using a mathematical model, e.g. a polynomial function, which involves coefficients. The present invention describes automated and semi-automated procedures for calibrating or adjusting the values of these coefficients. These procedures are based on the fitting of mathematical models on reference data extracted from specific regions of a wave front called reference areas, which are characterized by the fact that specimen contributions are a priori known in reference areas.