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Master theses

Current and past ideas and concepts for Master Theses.

Image restoration in a grating-based spectrometer


Photonic sensors, such as optical spectrometers, that convert physical quantities into readable signals, are becoming more widespread used in metrology and security applications. However, there is also an increased need of using spectroscopy in the process industry, food processing for yield improvement and environmental control. Increasing health awareness of citizens in Europe has led to an expanding demand for sensorial information. What is missing are novel and cost-effective methods to sense the desired analytes with high sensitivity, high reliability and sufficiently compact and portable devices, so that spectroscopic measurements can be carried out virtually everywhere. Thus, in our project, we develop a miniaturized high-performance optical spectrometer system, broadly applicable in various application domains.

The performance of any optical system suffers from a number of aberrations which can cause the image formed by the system to be blurred or distorted. It may be possible to minimize some of these aberrations by carefully designing a system, although the condition for minimizing one aberration may be different from minimizing others. Typically, this process is done by optimizing the shape of elements using optical system design software that very often results in complex polynomial or freeform surfaces.

However, it was shown [1][2] that rather than proposing new designs based on complicated optics, almost all aberrations can be partially or fully corrected by digital image processing. In this way, the requirements for the performance of the optical system can be softened and complexity be shifted towards computational algorithms.

Kind of work

In this master thesis, we aim to develop a method for aberration restoration in a grating- based spectrometer design. Such an optical spectrometer is an imaging system that maps a plurality of monochromatic images of the entrance slit onto the detector plane. In order to reach the goal, a potential master student will investigate deconvolution algorithms for optical aberrations correction, choose one/several of them and apply those to the images obtained with the demonstrator available at B-PHOT. The work may require an analysis of the optical system to get a better insight for choosing the right computational method.

Specific objectives
• Study state-of-the art on image restoration algorithms and literature overview
• Analyze the configuration of the grating-based spectrometer
• Exploring and benchmarking quantitatively the outcome of algorithms
• Propose and apply the restoration method using an existing lab-demonstrator

Framework of the Thesis

xCLASS Marie Curie ITN (

Number of Students


Expected Student Profile

Engineering, Mathematics of Physics student with a keen interest on improving his/her knowledge in computational imaging (optics and image processing).


Prof. Dr. Ir. Peter Schelkens

+32 (0)2 629 1681

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