Characterization of VNIR Hyperspectral Sensors with Monolithically Integrated Optical Filters

Agrawal, Prashant; Tack, Klaas; Geelen, Bert; Masschelein, Bart; Moran, Pablo Mateo Aranda; Lambrechts, Andy; Jayapala, Murali

doi:10.2352/issn.2470-1173.2016.12.imse-280

Cited by 15 publications

(7 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The experimental setup consists of a monochromator coupled to a collimating lens which illuminates the sensor. The setup and its operation is described in [32]. Several components of the setup were updated but the operational principle remains unchanged.…”

Section: Supplementary Materialsmentioning

confidence: 99%

Pixel-integrated thin-film filter simulation and scaling trade-offs

Goossens

2021

Preprint

View full text Add to dashboard Cite

Thin-film optical filters can nowadays be integrated onto pixels of commercial image sensors used for spectral imaging. A drawback of having more filters on an image sensor is a loss in spatial resolution which could be regained by using smaller pixels. However, this work shows that miniaturization causes a reduction in transmittance and requires a trade-off between pixel size and filter bandwidth. This is caused by diffraction and the reduced number of reflections in the filter. Analytical wave and ray optics models are developed and used for fast transmittance prediction and this is validated using a commercial spectral sensor and numerical simulations. The identified trade-off is an intrinsic limitation of pixel-integrated thin-film filter technology and the developed models will be useful tools for exploring new hardware and computational solutions.

show abstract

Section: Supplementary Materialsmentioning

confidence: 99%

Pixel-integrated thin-film filter simulation and scaling trade-offs

Goossens

2021

Preprint

View full text Add to dashboard Cite

show abstract

“…Figure 3. Chief Ray Angle (CRA) and cone of incidence angle as a function of pixel position ( -diameter of lens; -focal length) [3] In addition to the change in the peak wavelength, a decrease in the transmission of the filters for radiation arriving at a larger angle can also be expected. This is because the radiation is emitted laterally to the edge of the filter when the incidence is not perpendicular [1] .…”

Section: = ⋅ Cosmentioning

confidence: 99%

“…In [3] and [5] the angle dependence of the multispectral resolving filter-on-chip camera is pointed out and this is documented by diagrams showing the different filter transmission curves at different aperture numbers. However, the test setups used to determine these curves are not discussed in detail.…”

Section: State Of the Artmentioning

confidence: 99%

See 1 more Smart Citation

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

Dittrich

Bichra

Pfützenreuter

et al. 2019

Photonics and Education in Measurement Science 2019

View full text Add to dashboard Cite

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.

show abstract

“…As hyperspectral snapshot cameras generate data points p k (see Eq. (1)) within a single acquisition, they allow the detection of dynamic scenes [20][21][22]. In order to use them to measure the 3D shape of even unstructured or untextured surfaces with high accuracy and robustness, we employ the method of active close-range stereophotogrammetry [23][24][25][26][27].…”

Section: Introductionmentioning

confidence: 99%

5D hyperspectral imaging: fast and accurate measurement of surface shape and spectral characteristics using structured light

Heist¹,

Zhang²,

Reichwald³

et al. 2018

Opt. Express

View full text Add to dashboard Cite

Measuring the shape (coordinates x, y, z ) and spectral characteristics (wavelength-dependent reflectance R (λi)) of macroscopic objects as a function of time (t) is of great interest in areas such as medical imaging, precision agriculture, or optical sorting. Here, we present an approach that allows to determine all these quantities with high resolution and accuracy, enabling measurement in five dimensions. We call this approach 5D hyperspectral imaging. We describe the design and implementation of a 5D sensor operating in the visible to near-infrared spectral range, which provides excellent spatial and spectral resolution, great depth accuracy, and high frame rates. The results of various experiments strongly indicate the great benefit of the new technology.

show abstract

Characterization of VNIR Hyperspectral Sensors with Monolithically Integrated Optical Filters

Cited by 15 publications

References 0 publications

Pixel-integrated thin-film filter simulation and scaling trade-offs

Pixel-integrated thin-film filter simulation and scaling trade-offs

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

5D hyperspectral imaging: fast and accurate measurement of surface shape and spectral characteristics using structured light

Contact Info

Product

Resources

About