diff options
author | Nick White <git@njw.name> | 2019-10-08 15:49:52 +0100 |
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committer | Nick White <git@njw.name> | 2019-10-08 15:49:52 +0100 |
commit | 69aae6b93dcadd9e4895f86fe661ee80e79dcf9e (patch) | |
tree | bfc42b832a6d6e3051631eb6cf530e1400b2c080 /preproc/sauvola.go | |
parent | d43c11bf653bfe3c1ad1ed277f1ec08bf155cf98 (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.go | 76 |
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 -} |