GetNoise

Description :

This function allows to analyze a set of images based on a window statistic to perform noise tests. It returns rms noise expressed in ADUs
This function needs a window definition, an array of images.
It returns two images : a median stack image and an image showing defective pixels below/above +/- 5 sigmas with red or green crosses
It shows two plots, one is statistic row collapse, the other is statistic collumn collapse.

It also display noise results as following :
Noise : 4.516 ┬▒ 0.04179 ADU
Amount of pixels at +(green) -(red) 5 sigmas : 11
Threshold (ADU) : 14.21

Please have a look HERE to get important information about CCD testing functions.

Minimum version : 1.61

Syntax :

GETNOISE ImagesArray AmtImage X1 Y1 X2 Y2

Variables :

Parameters Inputs / Outputs Type Description
ImagesArray Input Array of images An array of images handles (that points the the pixel datas) that needs to be previously loaded.
AmtImage Input Integer Amount of images to analyze
X1 Input Integer Left bottom X image coordinates where the statistic will be computed
Y1 Input Integer Left bottom Y image coordinates where the statistic will be computed
X2 Input Integer Top right X image coordinates where the statistic will be computed
Y2 Input Integer Top right Y image coordinates where the statistic will be computed

See also :
GETCONVERFACTOR

Example :

Path$="C:\Prism\Images de test\ccd_test\noise\"

// Loads n1.cpa ... images

AmtImage=5

for i=1 AmtImage

str i i$
a$="n"+i$+".cpa"
a$=path$+a$
print a$
open ImagesArray[i-1] a$

next i

X1=200
Y1=200
X2=500
Y2=500

GETNOISE ImagesArray AmtImage X1 Y1 X2 Y2

for i=1 AmtImage

close ImagesArray[i-1]

next i