In-flight monitoring of the dead and bad pixel map

On this page:

Introduction


Each optical channel of the OMI instrument is equipped with a CCD of the frame transfer type. After exposure the measurement in the image section is rapidly transferred to the storage section. The storage section is then read out while the new exposure takes place in the image section. The performance of each individual pixel of both sections is monitored over the mission. This information is used to derive the Bad and Dead Pixel Map (BDPM), which is onwards used in the generation of level 1B and level 2 data. The BDPM used by the GDPS is updated by the TDOPF, using TMCF trending information. The graphs on this page show the evolution of all individual flags that are part of the BDPM. Input data consists of dark current, LED, WLS and RTS measurements; these are all unbinned. The DBPM in the level 1B data is created using a selecion of flags presented here, which are rebinned to the desired level 1B binning factor.

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Pixels Statistics


Evolution of total number of flagged pixels


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Evolution of total number of bad pixels


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Evolution of total number of dead pixels


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Evolution of total number of missing pixels


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Bad Pixels According to Type


Evolution of bad CTE pixels


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Evolution of bad dark current pixels


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Evolution of bad dark current noise pixels


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Evolution of bad LED pixels


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Evolution of bad LED noise pixels


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Evolution of bad RTS pixels


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Evolution of bad WLS pixels


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Evolution of bad WLS noise pixels


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Dead Pixels According to Type


Evolution of dead CTE pixels


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Evolution of dead dark current pixels


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Evolution of dead dark current noise pixels


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Evolution of dead LED pixels


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Evolution of dead LED noise pixels


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Evolution of dead RTS pixels


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Evolution of dead WLS pixels


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Evolution of dead WLS noise pixels


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Missing Pixels According to Type


Evolution of missing dark current pixels


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Evolution of missing LED pixels


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Evolution of missing WLS pixels


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Conclusion


The graphs indicate that approximately 0.6 % of the individual pixels are dead after 30.000 orbits. Both the UV and VIS channel show approximately the same behavior, but in some case distinct differences can be seen between the image and storage section.

For more information contact Quintus Kleipool or Marcel Dobber

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