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-rw-r--r--preproc/cmd/binarize/main.go78
1 files changed, 78 insertions, 0 deletions
diff --git a/preproc/cmd/binarize/main.go b/preproc/cmd/binarize/main.go
new file mode 100644
index 0000000..c274f9c
--- /dev/null
+++ b/preproc/cmd/binarize/main.go
@@ -0,0 +1,78 @@
+package main
+
+import (
+ "flag"
+ "fmt"
+ "image"
+ "image/draw"
+ _ "image/jpeg"
+ "image/png"
+ "log"
+ "os"
+
+ "rescribe.xyz/go.git/preproc"
+)
+
+// TODO: do more testing to see how good this assumption is
+func autowsize(bounds image.Rectangle) int {
+ return bounds.Dx() / 60
+}
+
+func main() {
+ flag.Usage = func() {
+ fmt.Fprintf(os.Stderr, "Usage: binarize [-k num] [-t type] [-w num] inimg outimg\n")
+ flag.PrintDefaults()
+ }
+ wsize := flag.Int("w", 0, "Window size for sauvola algorithm. Set automatically based on resolution if not set.")
+ ksize := flag.Float64("k", 0.5, "K for sauvola algorithm. This controls the overall threshold level. Set it lower for very light text (try 0.1 or 0.2).")
+ btype := flag.String("t", "binary", "Type of threshold. binary or zeroinv are currently implemented.")
+ flag.Parse()
+ if flag.NArg() < 2 {
+ flag.Usage()
+ os.Exit(1)
+ }
+
+ f, err := os.Open(flag.Arg(0))
+ defer f.Close()
+ if err != nil {
+ log.Fatalf("Could not open file %s: %v\n", flag.Arg(0), err)
+ }
+ img, _, err := image.Decode(f)
+ if err != nil {
+ log.Fatalf("Could not decode image: %v\n", 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 *wsize == 0 {
+ *wsize = autowsize(b)
+ log.Printf("Set window size to %d\n", *wsize)
+ }
+
+ if *wsize % 2 == 0 {
+ *wsize++
+ }
+
+ // TODO: come up with a way to set a good ksize automatically
+
+ var thresh image.Image
+ thresh = preproc.IntegralSauvola(gray, *ksize, *wsize)
+
+ if *btype == "zeroinv" {
+ thresh, err = preproc.BinToZeroInv(thresh.(*image.Gray), img.(*image.RGBA))
+ if err != nil {
+ log.Fatal(err)
+ }
+ }
+
+ f, err = os.Create(flag.Arg(1))
+ if err != nil {
+ log.Fatalf("Could not create file %s: %v\n", flag.Arg(1), err)
+ }
+ defer f.Close()
+ err = png.Encode(f, thresh)
+ if err != nil {
+ log.Fatalf("Could not encode image: %v\n", err)
+ }
+}