3 auto contrast, 4 histogram equalization, Auto contrast – Levenhuk C800 NG Digital Camera, USB 2.0 User Manual

Page 71: Histogram equalization

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63

Auto Level

gives good results when an image with an average distribution of pixel

values needs a simple contrast adjustment or when an image has an overall color
cast. However, adjusting the

Curves

manually is more precise.

See

Auto Contrast

for another auto adjust command.

11.2.3

Auto Contrast

The

Auto Contrast

command automatically adjusts the overall contrast and mixture

of colors in an RGB image. Since it does not adjust channels individually,

Auto

Contrast

does not introduce or remove color casts. It maps the lightest and darkest

pixels in the image to white and black, which makes highlights appear lighter and
shadows appear darker.

When identifying the lightest and darkest pixels on an image,

Auto Contrast

clips the

white and black pixels by

0.5%

--that is, it ignores the first

0.5%

of either extreme.

Choose

Options>Auto Correction•••

menu to modify this default setting. This

ensures that white and black values are representative without being determined by
extreme pixel values. The

Auto Correction•••

dialog is shown below:

Auto Contrast

can improve the appearance of many photographic or continuous-tone

images. It does not improve flat-color images.

See

Auto Level

for another auto operation.

11.2.4

Histogram Equalization

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