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authorNick White <git@njw.name>2019-07-25 17:53:26 +0100
committerNick White <git@njw.name>2019-07-25 17:53:26 +0100
commitab773582e72bf01e1cad71431d2ddea5f216cc07 (patch)
tree849b43a0855f81b813a3fd396e5c5edc2a8ba71f /preproc
parent56687b56558ced34b35955163bd5dd3697d578e8 (diff)
Add first draft of pipelinepreprocess - completely untested, will contain bugs
Diffstat (limited to 'preproc')
-rw-r--r--preproc/preprocmulti.go93
1 files changed, 93 insertions, 0 deletions
diff --git a/preproc/preprocmulti.go b/preproc/preprocmulti.go
new file mode 100644
index 0000000..cd7ad34
--- /dev/null
+++ b/preproc/preprocmulti.go
@@ -0,0 +1,93 @@
+package preproc
+
+// TODO: come up with a way to set a good ksize automatically
+
+import (
+ "fmt"
+ "image"
+ "image/draw"
+ _ "image/jpeg"
+ "image/png"
+ "os"
+ "strings"
+
+ "rescribe.xyz/go.git/integralimg"
+)
+
+// TODO: do more testing to see how good this assumption is
+func autowsize(bounds image.Rectangle) int {
+ return bounds.Dx() / 60
+}
+
+// PreProcMulti binarizes and preprocesses an image with multiple binarisation levels.
+// inPath: Path of input image.
+// ksizes: Slice of k values to pass to Sauvola algorithm
+// binType: Type of binarization threshold. binary or zeroinv are currently implemented.
+// binWsize: Window size for sauvola binarization algorithm. Set automatically based on resolution if 0.
+// wipe: Whether to wipe (clear sides) the image
+// wipeWsize: Window size for wiping algorithm
+// wipeMinWidthPerc: Minimum percentage of the image width for the content width calculation to be considered valid
+// Note: copied from cmd/preprocmulti/main.go, should think about the best way
+// to organise this code later.
+// TODO: return errors that encapsulate the err describing where it was encountered
+func PreProcMulti(inPath string, ksizes []float64, binType string, binWsize int, wipe bool, wipeWsize int, wipeMinWidthPerc int) ([]string, error) {
+ // Make outBase inPath up to final .
+ s := strings.Split(inPath, ".")
+ outBase := strings.Join(s[:len(s)-1], "")
+
+ var donePaths []string
+
+ f, err := os.Open(inPath)
+ if err != nil {
+ return donePaths, err
+ }
+ defer f.Close()
+ img, _, err := image.Decode(f)
+ if err != nil {
+ return donePaths, err
+ }
+ b := img.Bounds()
+ gray := image.NewGray(image.Rect(0, 0, b.Dx(), b.Dy()))
+ draw.Draw(gray, b, img, b.Min, draw.Src)
+
+ if binWsize == 0 {
+ binWsize = autowsize(b)
+ }
+
+ if binWsize%2 == 0 {
+ binWsize++
+ }
+
+ var clean, threshimg image.Image
+ integrals := integralimg.ToAllIntegralImg(gray)
+
+ for _, k := range ksizes {
+ threshimg = PreCalcedSauvola(integrals, gray, k, binWsize)
+
+ if binType == "zeroinv" {
+ threshimg, err = BinToZeroInv(threshimg.(*image.Gray), img.(*image.RGBA))
+ if err != nil {
+ return donePaths, err
+ }
+ }
+
+ if wipe {
+ clean = Wipe(threshimg.(*image.Gray), wipeWsize, k * 0.02, wipeMinWidthPerc)
+ } else {
+ clean = threshimg
+ }
+
+ savefn := fmt.Sprintf("%s_bin%0.1f.png", outBase, k)
+ f, err = os.Create(savefn)
+ if err != nil {
+ return donePaths, err
+ }
+ defer f.Close()
+ err = png.Encode(f, clean)
+ if err != nil {
+ return donePaths, err
+ }
+ donePaths = append(donePaths, savefn)
+ }
+ return donePaths, nil
+}