beautypg.com

Histogram corrections – Konica Minolta DiMAGE Scan Dual III AF-2840 User Manual

Page 76

background image

76

Histogram corrections

Input shadow slider

Input gamma slider

Input highlight slider

Input shadow text box

Input gamma text box

Output shadow slider

Output highlight slider

Output shadow text box

Output highlight text box

The color histograms can be displayed with the channel list box or with keyboard shortcuts. While
holding the control key (Windows) or command key (Macintosh), press 0 (zero) to display the
RGB channel, press 1 to display the red channel, 2 to display the green channel, 3 to display the
blue channel.

The histogram can be used to maximize the distribution of the pixels in the image. The highlight
level, shadow level, and gamma can be set manually with the sliders or text boxes.

The input gamma slider defines the mid-tones of the image. Dragging the input gamma slider to
the right will darken the image, and dragging it to the left will brighten it. Similar to the tone-curve
correction described on page 74, the input gamma slider allows the brightness of the image to be
adjusted without loosing image information.

The input highlight slider sets the white level. As the slider is moved to the left, an apparent
increase in contrast can be seen in the displayed image. All pixels to the right of the slider are set
to 255 and any image detail they may contain will be lost. This can be an important tool for
improving copy images of text on a white background. Uneven illumination, or faded or stained
paper can be distracting when copying text or line art. By adjusting the white level, the imperfec-
tions of the white background can be eliminated leaving only the darker text visible.

D

IMAGE SCAN DUAL III UTILITY

IMAGE PROCESSING

Input highlight text box