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authorNick White <git@njw.name>2019-10-08 15:49:52 +0100
committerNick White <git@njw.name>2019-10-08 15:49:52 +0100
commit69aae6b93dcadd9e4895f86fe661ee80e79dcf9e (patch)
treebfc42b832a6d6e3051631eb6cf530e1400b2c080 /preproc/sauvola.go
parentd43c11bf653bfe3c1ad1ed277f1ec08bf155cf98 (diff)
Remove parts that have been moved elsewhere, and rename to rescribe.xyz/utils
bookpipeline is now at rescribe.xyz/bookpipeline preproc is now at rescribe.xyz/preproc integralimg is now at rescribe.xyz/preproc/integralimg
Diffstat (limited to 'preproc/sauvola.go')
-rw-r--r--preproc/sauvola.go76
1 files changed, 0 insertions, 76 deletions
diff --git a/preproc/sauvola.go b/preproc/sauvola.go
deleted file mode 100644
index 046bb7d..0000000
--- a/preproc/sauvola.go
+++ /dev/null
@@ -1,76 +0,0 @@
-package preproc
-
-import (
- "image"
- "image/color"
-
- "rescribe.xyz/go.git/integralimg"
-)
-
-// 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)
-
- integrals := integralimg.ToAllIntegralImg(img)
-
- for y := b.Min.Y; y < b.Max.Y; y++ {
- for x := b.Min.X; x < b.Max.X; x++ {
- m, dev := integrals.MeanStdDevWindow(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
-}
-
-// PreCalcedSauvola Implements Sauvola's algorithm using precalculated Integral Images
-// TODO: have this be the root function that the other two reference
-func PreCalcedSauvola(integrals integralimg.WithSq, 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++ {
- m, dev := integrals.MeanStdDevWindow(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
-}