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Proceedings Paper • Open Access

Measurement of the modulation transfer function (MTF) of a camera lens
Author(s): Aline Vernier; Baptiste Perrin; Thierry Avignon; Jean Augereau; Lionel Jacubowiez

Paper Abstract

An accurate characterization of optical elements is one of the pivotal skills to be learnt in the context of undergraduate optics lab work or that of continuing education. We will show an experimental apparatus designed to measure the Modulation Transfer Function (MTF) of a camera lens. The educational scope of this apparatus ranges from the study of the aberrations of the lens and its suitability for use with a given sensor, to the design of the test bench itself. A first, purely visual observation allows the trainees to single-out the aberrations exhibited by an objective. The presence of the spherical and chromatic aberrations on the axis of the objective is thus identified, and a first estimate of the cut-off frequency of this objective can be given. There, the importance of the geometrical extent of the source and the impact of the optical elements of the test bench on the measurement can also be assessed. The second part of the experiment makes use of a CMOS camera to measure the Linear Spread Function (LSF) of the camera lens and the MTF is then retrieved by Fourier transform. The experimental setup consists of a fine slit as a source, a collimator, the studied objective exhibiting conspicuous aberrations and a microscope objective to re-image the LSF either for direct observation with an eye-piece or for analysis with the camera. The latter is performed with a home-developed Matlab software.

Paper Details

Date Published: 8 October 2015
PDF: 6 pages
Proc. SPIE 9793, Education and Training in Optics and Photonics: ETOP 2015, 97931I (8 October 2015); doi: 10.1117/12.2223114
Show Author Affiliations
Aline Vernier, Institut d'Optique Graduate School (France)
Baptiste Perrin, Institut d’Optique Graduate School (France)
Thierry Avignon, Institut d’Optique Graduate School (France)
Jean Augereau, Institut d’Optique Graduate School (France)
Lionel Jacubowiez, Institut d'Optique Graduate School (France)

Published in SPIE Proceedings Vol. 9793:
Education and Training in Optics and Photonics: ETOP 2015

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