User Guide

User Guide Neat Image
Copyright © 1999-2003 by ABSoft. All rights reserved.
19 20-Nov-03
5.1.2. Fine-tuning the rough device noise profile
For more accurate noise reduction, it is helpful to measure the dependence between the level of noise
and the local brightness in different image areas. This dependence should be taken into account if noise
appreciably depends on brightness (for example, if noise is strong in dark areas and weak in light areas).
The Fine-Tuning Analyzer measures this dependence. The measurements results are displayed by the
noise profile equalizer. Noise profile equalizer has nine sliders that represent the range of image
brightness from darkest to lightest for each sensor (R, G, B) of the image acquisition device.
The values of the equalizer sliders correspond to the estimated noise levels in different brightness
ranges relative to the rough noise profile. Positive values of sliders reflect higher estimated noise levels
and make Neat Image consider more image elements to be noise; negative values reflect lower
estimated noise levels and fewer image elements are considered noise in the corresponding brightness
ranges.
The Fine-Tuning Analyzer can be used in manual and automatic way. Below, the automatic method is
described first. Then the manual method is explained in details to provide understanding of the whole
process and result.
To automatically fine-tune the rough device noise profile
1) Enable Fine-Tuning Analyzer
⇒ Enable the Fine-Tuning Analyzer by checking the
checkbox
in the Fine-Tuning Analyzer box.
2) Apply Auto Fine-Tuning Analyzer
⇒ Click
(the Auto Fine-Tuning
Analyzer button) or select the Profile | Auto Fine-Tune
menu item.
The whole image will be automatically analyzed by Neat
Image and some of the equalizer sliders will receive the
‘measured’ status (see page 21). The values of other
sliders will be then automatically interpolated by the
Auto Complete function and will receive the ‘manual’
status.
You may want to inspect the equalizer values after
applying auto fine-tuning. In most cases, there is no need
to do manual slider adjustments afterwards. If you feel
this is necessary, please follow the guidelines given in the
manual fine-tuning subsection below.
To manually fine-tune the rough device noise profile
1) Find and select a 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 size of an image area can be from 30x30 to 300x300 pixels. The selection frame will change its
thickness according to the selection size. When you are selecting an image area, the selection status
on the bottom of the Fine-Tuning Analyzer box is dynamically indicating which frequency
1
components are contained in the selected area and would
be analyzed: ‘high’, ‘high+mid’, ‘high+mid+low’,
‘high+mid+low+very low freqs’.
1
See “what is frequency”, page 45.
See examples of uniform
image areas, page 31.