Mr. Mohamed Bichra Profile

Mohamed Bichra

PhD Student/Rsrch Assistant

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Publications (6)

Proceedings Article | 17 September 2019 Open Access

Measurement principle and arrangement for the determination of spectral channel-specific angle dependencies for multispectral resolving filter-on-chip CMOS cameras

P.-G. Dittrich, M. Bichra, C. Pfützenreuter, M. Rosenberger, G. Notni

Proceedings Volume 11144, 111440S (2019) https://doi.org/10.1117/12.2527871

KEYWORDS: Optical filters, Sensors, Cameras, Image sensors, CMOS sensors, Quantum efficiency, Photodiodes, Image filtering, Collimation, Calibration

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Filter-On-Chip CMOS sensor equipped cameras are a convenient, reliable and affordable approach for the parallel acquisition of spatial and spectral information. The combination of pixel-arranged spectral filter matrices on CMOS sensors increases their integration density and system complexity by several times compared to standard RGB cameras. Due to their system design, these cameras have an increased spectral crosstalk and specific dependencies from the angle of radiation. The paper will show how to develop and set up a measurement arrangement for the characterization of the channel specific spectral sensitivities under different angles of radiation. These characterizations are necessary to develop a more robust model for the camera pixel-value correction to ensure the comparability and reproducibility of the measured values. Therefore, a measurement setup to investigate the influence of the angle of incident radiation on filter-on-chip CMOS sensors was developed. After initial investigations with a setup in which the camera was simply rotated and investigations with a lens and changed f-number confirmed that the angle influence results in a measurable difference in the sensor response, a new measurement arrangement was developed to investigate this behavior more precisely. The developed measurement arrangement allows multispectral resolving image sensors to be radiated with collimated light at reproducible angles of incidence and with adjustable wavelengths. By comparing the measured values with illuminances measured using a calibrated photodiode in the same setup and with the same parameters, it is possible to evaluate the angle dependence based on quantum efficiency curves according to the EMVA 1288 standard. The investigations carried out, the developed principles and the realized semi-automatic measurement arrangement will be shown and explained to characterize the capabilities of multispectral resolving filter-on-chip CMOS sensor equipped cameras for applications in industry and biomedicine.

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Proceedings Article | 14 May 2019 Paper

Extended characterization of multispectral resolving filter-on-chip snapshot-mosaic CMOS cameras

P.-G. Dittrich, M. Bichra, D. Stiehler, C. Pfützenreuter, L. Radtke, M. Rosenberger, G. Notni

Proceedings Volume 10986, 109860I (2019) https://doi.org/10.1117/12.2518842

KEYWORDS: Cameras, Optical filters, Sensors, Quantum efficiency, CMOS sensors, Photons, Image sensors, RGB color model, CMOS cameras, Manufacturing

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SPIE Journal Paper | 22 August 2017

Experimental investigations on characterization of freeform wavefront using Shack–Hartmann sensor

Dali Burada, Kamal Pant, Mohamed Bichra, Gufran Khan, Stefan Sinzinger, Chandra Shakher

OE, Vol. 56, Issue 08, 084107, (August 2017) https://doi.org/10.1117/12.10.1117/1.OE.56.8.084107

KEYWORDS: Wavefronts, Photovoltaics, Sensors, Aspheric lenses, Diffractive optical elements, Freeform optics, Interferometry, Optical engineering, Metrology, Error analysis

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Proceedings Article | 26 June 2017 Paper

Development of metrology for freeform optics in reflection mode

Dali Burada, Kamal Pant, Vinod Mishra, Mohamed Bichra, Gufran Khan, Stefan Sinzinger, Chandra Shakher

Proceedings Volume 10329, 103291K (2017) https://doi.org/10.1117/12.2270284

KEYWORDS: Metrology, Optics manufacturing, Wavefront sensors, Freeform optics, Sensors, Optical testing, Fabrication, Manufacturing, 3D metrology, Projection systems, Wavefronts, Beam splitters, Reflection, Photovoltaics

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Proceedings Article | 13 May 2013 Paper

Parallelized chromatic confocal sensor systems

Matthias Hillenbrand, Adrian Grewe, Mohamed Bichra, Roman Kleindienst, Lucia Lorenz, Raoul Kirner, Robert Weiß, Stefan Sinzinger

Proceedings Volume 8788, 87880V (2013) https://doi.org/10.1117/12.2020334

KEYWORDS: Sensors, Confocal microscopy, Colorimetry, Detector arrays, Multiplexing, Imaging systems, Spectroscopy, Light sources, Prisms, RGB color model

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Proceedings Article | 18 December 2012 Paper

Chromatic information coding in optical systems for hyperspectral imaging and chromatic confocal sensing

M. Hillenbrand, A. Grewe, M. Bichra, B. Mitschunas, R. Kirner, R. Weiß, S. Sinzinger

Proceedings Volume 8550, 85500D (2012) https://doi.org/10.1117/12.981147

KEYWORDS: Colorimetry, Confocal microscopy, Imaging systems, Sensors, Chromatic aberrations, Hyperspectral imaging, Monochromatic aberrations, Spectral resolution, Point spread functions, Sensing systems

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Showing 5 of 6 publications

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