Sous-Étape A. Rough analysis

Rough analysis requires only one uniform featureless image area. You have to manually find and analyze it:

1. Find a uniform featureless image area

• Scroll, pan, zoom the image in the viewer in the Device Noise Profile tab to find a uniform image area.
  
  The area should be at least 60x60 pixels large. That is the minimum size; the recommended size is 100x100 pixels or more.
  
  See examples of uniform image areas.
  
  If you cannot find a uniform area in the input image, consider using an alternative regular image or use the Calibration Target as explained in Étape I. Case of building a profile using the Calibration Target.
  
  Use (the Show negative button) on the toolbar to temporarily turn the image into its negative. This can make finding the noise and noise-only areas easier in some cases.
  

2. Select found uniform image area

• Use the mouse to select a uniform image area: press the left button, drag the mouse and then release the button.
  
  The selection should be at least 60x60 pixels large; the recommended size is 100x100 pixels or more. The selection frame will change its thickness according to the selection size. When you are selecting an area, the selection status in the Rough Noise Analyzer box is dynamically indicating whether the chosen area is large enough for analysis.
  
  

  Warning

  The selection status displays "signal clipping!" when the image in some of the channels (R,G,B) is close to the dynamic range limit in the selected area. A device noise profile built using the selected area could be inaccurate. Please try to avoid this for best results.

3. Analyze selected image area with Rough Noise Analyzer

• Click    (the Rough Noise Analyzer button) in the Rough Noise Analyzer box or select the Profile | Build Rough Profile Using Selected Area menu item.
  
  Neat Image will measure the noise characteristics of the image acquisition device by analyzing the selected uniform image area. You only have to make this analysis once to create a rough noise profile.

Sous-Étape A :: Sous-Étape B