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authorNick White <git@njw.name>2019-04-18 13:24:02 +0100
committerNick White <git@njw.name>2019-04-18 13:24:02 +0100
commit4eb86764539a99b0d7c843d4aa81bfb2955db13c (patch)
tree1af1349c34de6b31829867baf18e31fa218cd191 /cleanup
parent75173a030b1f3eb8a1e161ffd1732daa40a5e178 (diff)
Add basic cleanup tool; working, but more refinements planned.
This uses integral image calculations, so they have been exported in the binarization package
Diffstat (limited to 'cleanup')
-rw-r--r--cleanup/main.go129
1 files changed, 129 insertions, 0 deletions
diff --git a/cleanup/main.go b/cleanup/main.go
new file mode 100644
index 0000000..05ff5f2
--- /dev/null
+++ b/cleanup/main.go
@@ -0,0 +1,129 @@
+package main
+
+import (
+ "flag"
+ "fmt"
+ "image"
+ "image/color"
+ "image/draw"
+ _ "image/jpeg"
+ "image/png"
+ "log"
+ "os"
+
+ "rescribe.xyz/go.git/binarize"
+)
+
+type windowslice struct {
+ topleft uint64
+ topright uint64
+ bottomleft uint64
+ bottomright uint64
+}
+
+func getwindowslice(i [][]uint64, x int, size int) windowslice {
+ maxy := len(i)-1
+ maxx := x+size
+ if maxx > len(i[0])-1 {
+ maxx = len(i[0])-1
+ }
+
+ return windowslice { i[0][x], i[0][maxx], i[maxy][x], i[maxy][maxx] }
+}
+
+// checkwindow checks the window from x to see whether more than
+// thresh proportion of the pixels are white, if so it returns true.
+func checkwindow(integral [][]uint64, x int, size int, thresh float64) bool {
+ height := len(integral)
+ window := getwindowslice(integral, x, size)
+ // divide by 255 as each on pixel has the value of 255
+ sum := (window.bottomright + window.topleft - window.topright - window.bottomleft) / 255
+ area := size * height
+ proportion := float64(float64(area) / float64(sum)) - 1
+ return proportion <= thresh
+}
+
+// cleanimg fills the sections of image not within the boundaries
+// of lowedge and highedge with white
+func cleanimg(img *image.Gray, lowedge int, highedge int) *image.Gray {
+ b := img.Bounds()
+ new := image.NewGray(b)
+
+ // set left edge white
+ for x := b.Min.X; x < lowedge; x++ {
+ for y := b.Min.Y; y < b.Max.Y; y++ {
+ new.SetGray(x, y, color.Gray{255})
+ }
+ }
+ // copy middle
+ for x := lowedge; x < highedge; x++ {
+ for y := b.Min.Y; y < b.Max.Y; y++ {
+ new.SetGray(x, y, img.GrayAt(x, y))
+ }
+ }
+ // set right edge white
+ for x := highedge; x < b.Max.X; x++ {
+ for y := b.Min.Y; y < b.Max.Y; y++ {
+ new.SetGray(x, y, color.Gray{255})
+ }
+ }
+
+ return new
+}
+
+func main() {
+ flag.Usage = func() {
+ fmt.Fprintf(os.Stderr, "Usage: cleanup [-t thresh] [-w winsize] inimg outimg\n")
+ flag.PrintDefaults()
+ }
+ wsize := flag.Int("w", 5, "Window size for mask finding algorithm.")
+ thresh := flag.Float64("t", 0.05, "Threshold for the proportion of black pixels below which a window is determined to be the edge.")
+ 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)
+
+ integral := binarize.Integralimg(gray)
+ maxx := len(integral[0])-1
+ var lowedge, highedge int = 0, maxx
+ // find right edge
+ for x := maxx / 2; x < maxx - *wsize; x++ {
+ if checkwindow(integral, x, *wsize, *thresh) {
+ highedge = x
+ break
+ }
+ }
+ // find left edge
+ for x := maxx / 2; x > 0; x-- {
+ if checkwindow(integral, x, *wsize, *thresh) {
+ lowedge = x
+ break
+ }
+ }
+
+ clean := cleanimg(gray, lowedge, highedge)
+
+ 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, clean)
+ if err != nil {
+ log.Fatalf("Could not encode image: %v\n", err)
+ }
+}