# CCD Corrections¶

The following documentation has been extracted automatically from the comments found in the source code. Discard Parameters. object variable.

class Parameters_module.Parameters

The input variables are read from the input file. The input file is written with python syntax. The Input file is interpreted as python after a preprocessing The preprocessing was introduced at the time of HST-> PYHST transition to maintaing compatibility with:

• NO/YES meaning 0/1

• items containing FILE in their name can be initialized without using the “” which are otherwise necessary for strings

The input file has to set (some of) the following variables. To setup easily an input file you are suggested to start from one of the examples given in the doc.

CCD_FILTER = ''
This variable is a string containing the name of the method. The available options are:
• “CCD_Filter” : a median filter is applied on the 3X3 neighbour of every pixel. If the pixel value ( the higher the more photons) exceed the median value more then the “threshold” parameter then the pixel value is replaced by the median value.

CCD_FILTER_PARA = {}
This parameter is a python dictionary containing all the necessary parameters :
• for option “CCD_Filter”, only threshold is necessary. The dictionary will then be of the form : {“threshold”: 0.040000 }

DO_CCD_FILTER = 0

Setting this parameter to 1 activates a filtering on each projection. The treatement is applied after : -background subtraction -division by the flat-field -double FF correction … if these options are activated.