français [modifier]
English
Deutsch
Français
Italiano
日本語
Español
Português
Russian
Chinese (Simp.)
Tchèque
Polonais (seulement boutique)
|
2.3.7 Why was the Histogram developed?
|
||||
|
A histogram is a graphical display of the frequency distribution, for example, of gray scales or color values, or even brightness values. The more bright pixels (or bright red/green/blue colors) that are present in an image, the higher the amplitude of the display; the more levels, the wider the histogram will be. The SilverFast 16-bit histogram doubles the dynamics that can be perceived, making correct evaluation of the images possible.
How Does the SilverFast Histogram Work? With the 16-bit histogram, every gray or color value that appears in the image is shown with its frequency (amplitude of the individual point). This creates a "mountain range" of the gray values present. Pure black corresponds to the value 0 and pure white to the value 65536. Depending on the screen resolution, up to 1600 tonal values can be differentiated and used to control the optimum result. The 16 bit densitometer is a supporting tool, which can measure each image point (for each color) with up to 65536 tonal values. This permits the dynamics, also called the contrast range, of the original to be evaluated. Gaps in the histogram indicate gray scale losses in the input device or processing. Highlights and shadows, as well as midtones, can be set in an optimum manner. 
|
||||
