It generates halftone image using any of three different methods proposed by Frankie Sierra.
y = sierra(x)
y = sierra(x,opt)
A matrix representing a gray scale image whose halftone image will be generated.
A number 1, 2 or 3 to select option for any of three methods proposed by Sierra.
A binary matrix representing the halftone image of the input gray scale image.
It computes the haftone image of a gray scale image by using any of the three methods proposed by Frankie Sierra. It takes two input arguments. The first input is the matrix representing a gray scale image. The second input is one of the numbers 1,2 or 3. By default, the second argument opt is taken as 1 correspoding to Sierra's hlftoning using Filter-lite. If opt=2, then haltoning is done using Sierra's 3x5 filter and if opt=3,hlftoning is done using Sierra's 5x5 filter.