diff options
| -rw-r--r-- | binarize/main.go | 35 |
1 files changed, 23 insertions, 12 deletions
diff --git a/binarize/main.go b/binarize/main.go index aa8d4ee..ec99c09 100644 --- a/binarize/main.go +++ b/binarize/main.go @@ -14,23 +14,24 @@ import ( "os" ) +// 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 [-w num] [-k num] inimg outimg\n") flag.PrintDefaults() } - wsize := flag.Int("w", 31, "Window size for sauvola algorithm (needs to be odd)") - ksize := flag.Float64("k", 0.5, "K for sauvola algorithm") + 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).") flag.Parse() if flag.NArg() < 2 { flag.Usage() os.Exit(1) } - if *wsize % 2 == 0 { - *wsize++ - } - f, err := os.Open(flag.Arg(0)) defer f.Close() if err != nil { @@ -42,18 +43,28 @@ func main() { } b := img.Bounds() gray := image.NewGray(image.Rect(0, 0, b.Dx(), b.Dy())) - draw.Draw(gray, b, img, b.Min, draw.Src) + 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 - // TODO: estimate an appropriate window size based on resolution thresh := IntegralSauvola(gray, *ksize, *wsize) f, err = os.Create(flag.Arg(1)) - if err != nil { + 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 { + if err != nil { log.Fatalf("Could not encode image: %v\n", err) - } + } } |