Advanced Topics

Fixed Pattern Noise (FPN) Correction

Fixed Pattern Noise Correction intends to eliminate fixed pattern noise from an image. The user may correct

their images either post capture or automatically during the image acquisition process. For more information

on this system please click here.

Flat Field Correction (FFC)

Flat Field Correction intends to eliminate pixel to pixel brightness variation in an image. The user may correct

their images either post capture or automatically during image acquisition. For more information on this system

please click here.

Master Dark Frame Library

A master dark frame library is a collection of dark frames that can be used to correct for fixed pattern noise

generated by the camera. Fixed pattern noise is affected by the temperature of the sensor, the exposure time of

images, and the gain settings of images. The master dark frame library is a compilation of dark frames

captured at varying gains, exposure times, and temperatures, which can then be used for later images taken at

the same or similar conditions.

It is good practice to save any dark frames taken, and label them in the file name. This will accrue a library of

usable dark frames which can then be used for images taken under similar conditions.

Master Flat Frame Library

A master flat frame library is a collection of flat frames that can be used to correct pixel to pixel brightness

variation in an image. Flat frame correction is dependent on the mean pixel brightness of an image, and thus a

master flat frame library contains images that have many mean brightness values. Additionally, an images gain

as well as any hardware that influences the light captured by the sensor will change the pixel to pixel brightness

values and thus need to be accounted for in the flat frame library. Thus, flat frames correction will need to be

used with a flat frame of the same gain, hardware, and mean pixel value.

It is good practice to save any flat frames taken with the gain, mean pixel value, and any hardware that may be

subject to variation (Ex: filter wheel position, aperture, lens type). This will allow the user to compile a collection

of flat frames that can be used in future instances.

Note: Due to the nature of flat frames, small changes in hardware or settings can influence the effectiveness of

the capture. In cases where very precise correcting is required, the flat frame library will need to be remade

regularly to account for changes that cannot be predicted (Ex: dust, lens position, focal point, and ware and tear

of optical parts between use).