Reorganise image manipulation to separate integral image parts

Also unify everything else under preproc/

Note that the UsefulImg interface should be used by the main
functions, to simplify things, but this hasn't been done yet.

1 files changed, 0 insertions, 54 deletions

diff --git a/binarize/sauvola.go b/binarize/sauvola.go
deleted file mode 100644
index 6d9c1af..0000000
--- a/binarize/sauvola.go
+++ /dev/null
@@ -1,54 +0,0 @@
-package binarize
-
-import (
-	"image"
-	"image/color"
-)
-
-// Implements Sauvola's algorithm for text binarization, see paper
-// "Adaptive document image binarization" (2000)
-func Sauvola(img *image.Gray, ksize float64, windowsize int) *image.Gray {
-	b := img.Bounds()
-	new := image.NewGray(b)
-
-	for y := b.Min.Y; y < b.Max.Y; y++ {
-		for x := b.Min.X; x < b.Max.X; x++ {
-			window := surrounding(img, x, y, windowsize)
-			m, dev := meanstddev(window)
-			threshold := m * (1 + ksize * ((dev / 128) - 1))
-			if img.GrayAt(x, y).Y < uint8(threshold) {
-				new.SetGray(x, y, color.Gray{0})
-			} else {
-				new.SetGray(x, y, color.Gray{255})
-			}
-		}
-	}
-
-	return new
-}
-
-// Implements Sauvola's algorithm using Integral Images, see paper
-// "Efficient Implementation of Local Adaptive Thresholding Techniques Using Integral Images"
-// and
-// https://stackoverflow.com/questions/13110733/computing-image-integral
-func IntegralSauvola(img *image.Gray, ksize float64, windowsize int) *image.Gray {
-	b := img.Bounds()
-	new := image.NewGray(b)
-
-	integral := Integralimg(img)
-	integralsq := integralimgsq(img)
-
-	for y := b.Min.Y; y < b.Max.Y; y++ {
-		for x := b.Min.X; x < b.Max.X; x++ {
-			m, dev := integralmeanstddev(integral, integralsq, x, y, windowsize)
-			threshold := m * (1 + ksize * ((dev / 128) - 1))
-			if img.GrayAt(x, y).Y < uint8(threshold) {
-				new.SetGray(x, y, color.Gray{0})
-			} else {
-				new.SetGray(x, y, color.Gray{255})
-			}
-		}
-	}
-
-	return new
-}