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) } }