HARFA: SCREENSHOTS AND TUTORIALS: NOISE SUBSTRACTION   Corrections Noise Substraction The images prepared by a CCD cam are influenced by the time-dependant thermal noise of the CCD cam (fig. 1). Fig. 1: The Pure Noise Image of a CCD (noise pronounced) To obtain noise corrected pictures, it's neccessary to perform Noise Substraction. We need Pure Noise Image. It is the image scanned by the closed (darken) optical system of CCD. The noise image have to be of the same size as the corrected image. Next, we have to load the Image To Be Corrected and the Pure Noise Image to HarFA (using Change button). Then HarFA user should press the Perform button, and the Noise Subtraction will be performed. Previous Next