The absolute sensitivity of digital colour cameras

Sigernes, F.; Dyrland, M. E.; Peters, Nial; Lorentzen, D. A.; Svenøe, T.; Heia, Karsten; Chernouss, S. A.; Deehr, C. S.; Kosch, M. J.

doi:10.1364/oe.17.020211

Cited by 41 publications

(33 citation statements)

References 3 publications

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“…This requires a more complex calibration procedure than used in this study, but is certainly feasible for experienced personnel with a wellequipped darkroom (e.g., Sigernes et al, 2009). Ongoing monitoring of photometric stability could be carried out using stellar sources, and periodic tests carried out with a field calibration source.…”

Section: Discussionmentioning

confidence: 99%

“…This means that, in contrast to Sigernes et al (2008Sigernes et al ( , 2009, our results cannot be used for absolute sensitivity (i.e., counts/Rayleigh) comparisons between different cameras. They do, however, provide simultaneous self-consistent results for all color channels on each CCD.…”

Section: Color Camerasmentioning

confidence: 95%

“…Partamies et al (2007) present a comparison of wide-band color mosaic imager and narrowband photometer observations, Sigernes et al (2008Sigernes et al ( , 2009 provide absolute spectral calibration of several different DSLR (digital single-lens reflex) cameras, and Partamies et al (2012) apply tomography to color mosaic images.…”

Section: Introductionmentioning

confidence: 99%

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Auroral spectral estimation with wide-band color mosaic CCDs

Jackel

Unick

Syrjäsuo

et al. 2014

Geosci. Instrum. Method. Data Syst.

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Abstract. Optical aurora can be structured over a wide range of spatial and temporal scales with spectral features that depend on the energy of precipitating particles. Scientific studies typically combine data from multiple instruments that are individually optimized for spatial, spectral, or temporal resolution. One recent addition combines all-sky optics with color mosaic CCD (charge-coupled device) detectors that use a matrix of different wide-band micro-filters to produce an image with several (often three) color channels. These devices provide sequences of two dimensional multispectral luminosity with simultaneous exposure of all color channels allowing interchannel comparison even during periods with rapidly varying aurora. At present color auroral image data are primarily used for qualitative analysis. In this study a quantitative approach based on Backus-Gilbert linear inversion was used to better understand the effective spectral resolution of existing and proposed instruments.Two spectrally calibrated commercial detectors (Sony ICX285AQ and ICX429AKL) with very different color mosaics (RGB (red, green, blue) vs. CYGM (cyan, yellow, green, magenta)) were found to have very similar spectral resolution: three channels with FWHM (full-width halfmaximum) ≈ 100 nm; a NIR (near infrared) blocking filter is important for stabilizing inversion of both three-channel configurations. Operating the ICX429AKL in a noninterlaced mode would improve spectral resolution and provide an additional near infrared channel. Transformations from arbitrary device channels to RGB are easily obtained through inversion. Simultaneous imaging of multiple auroral emissions may be achieved using a single-color camera with a triplepass filter. Combinations of multiple cameras with simple filters should provide ∼ 50 nm resolution across most of the visible spectrum. Performance of other instrument designs could be explored and compared using the same quantitative framework.

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Section: Discussionmentioning

confidence: 99%

Section: Color Camerasmentioning

confidence: 95%

See 1 more Smart Citation

Auroral spectral estimation with wide-band color mosaic CCDs

Jackel

Unick

Syrjäsuo

et al. 2014

Geosci. Instrum. Method. Data Syst.

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“…The peak values for the red, green, and blue channels, respectively, are situated at 590, 540 and 470 nm. Surprisingly, the experiment conducted by Sigerness et al [ 8 ] with a similar camera exhibited a different behavior where the blue channel would be predominant over the green and red ones, but these authors used different camera settings and especially a higher 1600 ISO sensitivity as well as 4 s of exposure time. The use of a different measurement unit also makes it difficult to compare the absolute sensitivity values.…”

Section: Raw Spectral Responsementioning

confidence: 97%

Color sensitivity of the multi-exposure HDR imaging process

Lenseigne¹,

Jacobs²,

Withouck

et al. 2013

Advanced Optical Technologies

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Multi-exposure high dynamic range(HDR) imaging builds HDR radiance maps by stitching together different views of a same scene with varying exposures. Practically, this process involves converting raw sensor data into low dynamic range (LDR) images, estimate the camera response curves, and use them in order to recover the irradiance for every pixel. During the export, applying white balance settings and image stitching, which both have an influence on the color balance in the final image. In this paper, we use a calibrated quasi-monochromatic light source, an integrating sphere, and a spectrograph in order to evaluate and compare the average spectral response of the image sensor. We finally draw some conclusion about the color consistency of HDR imaging and the additional steps necessary to use multi-exposure HDR imaging as a tool to measure the physical quantities such as radiance and luminance.

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“…Dicha eficiencia depende de la sensibilidad del ISO utilizado durante la adquisición de los videos. Las medidas realizadas por Sigernes (2009) confirman que para un ISO de 1600, la intensidad resultante es igual a 500 R/Å para una longitud de onda λ = 4000Å, en donde R es la reflectancia direccional espectral, una medida del flujo monocromático registrado por el detector en el experimento realizado por el autor. Para el mismo ISO pero en λ = 5800Å, el flujo aumenta a 3300 R/Å y finalmente en λ = 7000Å el flujo es 1500 R/Å.…”

Section: Idunclassified

Análisis comparativo de seis lugares de interés para la ubicación de instrumentación astronómica en Colombia

Pinzón

González

Ramírez

2016

Rev. Acad. Colomb. Cienc. Ex. Fis. Nat.

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ResumenEn este trabajo se presentan los resultados de una campaña observacional de tres años durante la cual se realizaron medidas de la calidad del cielo in-situ en seis sitios de interés astronómico en los departamentos de Santander, Boyacá, Tolima, Huila, Cesár y La Guajira. Se realizaron excursiones esporádicas y de corta duración a estos seis lugares con el fin de realizar mediciones de temperatura y humedad a lo largo de la noche, del nivel de turbulencia en la vecindad del telescopio ó Seeing, del brillo del cielo y de la extinción atmosférica. La metodología utilizada en las medidas del Seeing se validó a través del uso de imágenes satelitales simultáneas a nuestras visitas, obtenidas de la base de datos del satelite geoestacionario GOES 13. El Seeing es altamente variable a lo largo de la noche en todos los sitios, con valores entre 1" y 4". Las difíciles condiciones climatológicas en especial la elevada humedad registrada durante la campaña, impidieron obtener una estadística mínima de datos fotométricos por lo que el análisis comparativo de los lugares visitados está basado en las medidas de Seeing. Una prueba de Kolmogorov-Smirnov confirma que los valores más bajos se registraron en los lugares de mayor altura en el Oriente colombiano, en particular en el sitio La Bricha, una vereda del municipio de Macaravita en Santander en donde la variabilidad registrada fué la menor con un rms = 0,59′′. Este hecho sumado a la humedad inferior a 85% incluso durante la madrugada y el bajo nivel observado en el brillo de cielo sugieren que de los lugares visitados durante la campaña, La Bricha puede considerarse como un sitio apropiado para la ubicación de instrumentación astronómica en el rango óptico. No obstante, se recomienda realizar un monitoreo a largo plazo con el fin de caracterizar completamente el lugar. Palabras clave: turbulencia atmosférica, búsqueda de sitio en Colombia, GOES 13. Comparative analysis of six interesting sites for astronomical instrumentation in Colombia AbstractIn this work we present the results obtained from an observational campaign aimed to conduct measurements in-situ of the quality of the sky at six sites with astronomical interest in Santander, Boyacá, Tolima, Huila, Cesár and La Guajira. Short and sporadic expeditions were done to those places with the main goal to conduct measurements of temperature, humidity during the night, the level of turbulence in the vicinity of the telescope, the Seeing, the sky brightness and the atmospheric extinction. The adopted methodology for the Seeing measurements was validated with satellite data simultaneous to our visits, obtained from the data archive of the geostationary satellite GOES 13. All sites present Seeing highly variable along the night with values between 1′′ and 4′′. The bad weather and specially, the high humidity registered during the campaign limited the quality of photometric data and subsequently, the comparative analysis of the visited sites is based on the Seeing measurements. An statistical KolmogorovSmirnov test confir...

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The absolute sensitivity of digital colour cameras

Cited by 41 publications

References 3 publications

Auroral spectral estimation with wide-band color mosaic CCDs

Auroral spectral estimation with wide-band color mosaic CCDs

Color sensitivity of the multi-exposure HDR imaging process

Análisis comparativo de seis lugares de interés para la ubicación de instrumentación astronómica en Colombia

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