It won't hurt SNR and will help you to get rid of cold/defect/hot pixels before the actual integration starts.įor instance, I used to calibrate data of my Nikon D5100 BCF mod in the following way: The Bad Pixel Map should be used always for both lights and flat frames, if you have one. I would only advise to not use a MasterDark if you don't have significant fixed patterns in the dark current of your sensor, or if you can dither the fixed patterns away, usually, you would need strong dithering (more than 20 pixels) then. No not really, the Bad Pixel Map can be used with or without a Master Dark. Once APP is finished with creating the Bad Pixel Map, it will be saved to your current Working Directory: On the other hand, when you create a Master Dark or Master Flat, an outlier rejection filter can be used to create a better Master Dark or Master Flat.įor your convenience, when you create the Bad Pixel Map, APP will ignore the ourlier rejection filter options that are selected. The reason being: when you create a Bad Pixel Map, you shouldn't use any outlier rejection filter at all while integrating the flats and darks to be able to better detect these spurious pixels. When it's finished no Master Dark or Master Flat is being saved to your disc, only a Bad Pixel Map. Now click on calibrate to create the Bad Pixel Map.ĪPP will integrate your darks and flats and will perform analysis on the integrations to subtract the hot and cold pixels of your camera's sensor. Usually a value of 2-3 kappa works perfectly to remove almost all hot pixels or hot columns if you have these on your sensor. With noise the gaussian MRS (Multi Resolution Scale) noise estimate of the integrated master darks created from the darks. "COLD" when ADU value of pixel (greater than) localMedian + ( hot pixels kappa* noise) The cold pixel % is a percentage of the median value of the integrated master flat that will be constructed from your flats. Then select "create bad pixel map" and set 2 parameters for hot and cold detection in your flats and darks. Load the 5 darks and 5 flats and go to 2) CALIBRATE, scroll down to Bad Pixel Map, see screenshot: I am using 5 darks and 5 flats in this example from his Nikon D750. ( I have been using one successfully for more than 3 years now for a Nikon D5100 BCF mod, firmware hacked with the nikonhacker true dark current patch). The Bad Pixel Map is a Master Calibration frame that you only need to create once per year or a couple of years. These will be detected using dark frames.įor the detection of the cold pixels, only a couple of flats are needed to extract them robustly and add them to the bad pixel map.įor the detection of the hot pixels, you need to supply at least 20 darks and more is always better in this case.
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