Ximagic GrayDither
Home
Contact
Denoiser
    Download
    Usage
    Tutorial
    Examples
    Changelog
    License
Quantizer
    Download
    Usage
    Examples
    Changelog
    License
GrayDither
    Download
    Usage
    Examples
    Changelog
    License

Usage


screenshot

The plugin accept RGB color and grayscale images.

The RGB color images are converted automatically to grayscale using Y of YCbCr colorspace

Output gray levels The grayscale image can be converted to n-level grayscale, the 2 level grayscale is a B/W bitmap
Ordered dithering is the first step. It is not quantization error dependent as is the error dithering step. It can be used with or without further quantization.
  • Levels x Channel: The ordered quantization filter reduces levels of color of each channel. Each value can be from 2 to 256. When 256 is selected, the result is the same image
  • Ordered
    • Pattern: Select one from the values. There are diffusion and halftone patterns.
  • Ordered user defined
    • Pattern: Select one of the values.
    • Load Button to load an user threshold pattern from a file. The file must have the format explained in the user Threshold pattern (below).
    • Delete Button to delete the selected user threshold pattern
  • Calculated
    • Shape Circle
    • W Horizontal distance between center of shapes
    • H Vertical distance between center of shapes
  • Random
Error Dithering is the third step and it can be selected only if Quantization is selected. There are two main methods, arrays and space filling curve
  • % Error propagation Value of error diffused default 100%.
  • Array
    • Methods
      • Floyd-Steinberg
      • Ulichney
      • Fan
      • Jarvis
      • Stucki
      • Sierra3
      • Sierra2
      • Sierra42A
    • Serpentine scan Select serpentine scan of image.
  • Space filling curve
    • Methods
      • Riemersma
    • Queue size Number of pixels remembered
Postprocessing DBS (Direct binary search) This is a experimental feature and applicable only on bilevel images. After a transformation, the algorithm compares the initial image with the transformed one and try to adjust the final one, analyzing each pixel and its surroundings.

user_threshold

User Threshold pattern

User Threshold patterns can be loaded from files with the appropriate format or from images.
After a pattern is loaded it remain stored until the user deletes it.
The maximum pattern size is 262144 (width*height)

To load from a file
  • The file format should be:

    [width] [height]
    [matrix row 1 values separated by blanks]
    [matrix row 2 values separated by blanks]
    ...
    [matrix row n values separated by blanks]
    An example file
  • Method
    • Start Ximagic Quantizer and push the load button in the user threshold line
    • In the load dialog fill the pattern name, select "from file", fill the file name and push the ok button
To load from an image
  • The 1st channel of the current transformed image in the plugin will be imported as a threshold matrix
    Image of the pattern Diffusion 8x8
    Image of the pattern Halftone orthogonal 8x8
  • Method:
    • Open the threshold image in the editor.
    • Start Ximagic Quantizer.
    • Push the Load button in the user threshold line
    • In the load dialog, fill the pattern name, select from image, and push ok button.
    • When the image is loaded, a message box with the width and height of the pattern will appear.
    • The plugin will end. The image selected in the editor is the threshold and the plugin should end to allow the user to select another image.