instruments:tsi:tsi
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| instruments:tsi:tsi [2020/02/06 08:19] – [Specifications] jan | instruments:tsi:tsi [2024/07/02 14:38] (current) – [Principle] jan | ||
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| Channels are in the visible range with average wavelengths of ~650nm (red), ~510nm (green), ~465nm (blue), have a broad spectral sensitivity and do overlap. Peak sensitivity wavelengths are at 560nm (red), 530nm (green) and 430nm (blue) (at least these are the peak sensitivities of our visual system which a camera tries to mimic). But unfortunately the system is not calibrated: the camera adapts its exposure to received light (i.e. sensitivity changes in time). White balance is set to a constant value to ensure that sensitivity of the channels relative to each other is constant. Every 15minutes is varied exposure (collecting time of the sensor) and gain (amplifier within the sensor) which might be used to derive an absolute calibration. | Channels are in the visible range with average wavelengths of ~650nm (red), ~510nm (green), ~465nm (blue), have a broad spectral sensitivity and do overlap. Peak sensitivity wavelengths are at 560nm (red), 530nm (green) and 430nm (blue) (at least these are the peak sensitivities of our visual system which a camera tries to mimic). But unfortunately the system is not calibrated: the camera adapts its exposure to received light (i.e. sensitivity changes in time). White balance is set to a constant value to ensure that sensitivity of the channels relative to each other is constant. Every 15minutes is varied exposure (collecting time of the sensor) and gain (amplifier within the sensor) which might be used to derive an absolute calibration. | ||
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| + | The camera follows the equisolid model, that means that every pixel receives radiation from solid angles of the same size. That means radius $R$ in the image relative to radius of the horizon $R_0$ follows roughly the sine of the half zenith angle $\theta$, i.e. $ R = R_0 \cdot \sin(\theta/ | ||
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| The camera replaced a [[instruments: | The camera replaced a [[instruments: | ||
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| * If you are interested in receiving data please contact the instrument mentor [[http:// | * If you are interested in receiving data please contact the instrument mentor [[http:// | ||
| - | * recent plots can be found in the [[http://gop.meteo.uni-koeln.de/ | + | * recent plots can be found in the [[http://atmos.meteo.uni-koeln.de/ |
| - | [[http://gop.meteo.uni-koeln.de/ | + | [[http://atmos.meteo.uni-koeln.de/ |
| - | [[http://gop.meteo.uni-koeln.de/ | + | [[http://atmos.meteo.uni-koeln.de/ |
| Click on figure for further plots. | Click on figure for further plots. | ||
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| | Wavelengths / nm | ~560, ~540, ~420 | freq. of peak sensitivities of human eye (=> | | Wavelengths / nm | ~560, ~540, ~420 | freq. of peak sensitivities of human eye (=> | ||
| | Repetition Rate / s | 20 | Adjustable | | Repetition Rate / s | 20 | Adjustable | ||
| - | | resolution / deg | 0.15 | Resolutiuon | + | | resolution / deg | 0.15 | Resolution |
| - | | Field-of-View / deg | 90 | cloud classification | + | | Field-of-View / deg | 90 | cloud classification |
| | image size / pixel | 800x600 (=0.46MPx) | | image size / pixel | 800x600 (=0.46MPx) | ||
| | image size / pixel | 316 (=0.30MPx) | radius to horizon | | image size / pixel | 316 (=0.30MPx) | radius to horizon | ||
| - | | Sensitivity / (mV Lux$^{-1}$s$^{-1}$)) | 1300 | According to Datasheet of sensor. \\ We have no access to the voltage. | + | | Sensitivity / (mV Lux<sup>-1</ |
| | dyn.range / dB | 69 | | | dyn.range / dB | 69 | | ||
| | max S/N / dB | 37 | | | max S/N / dB | 37 | | ||
instruments/tsi/tsi.1580977194.txt.gz · Last modified: by jan