From bf8614ea51cf9f84018bee5f46667d8d42c94b20 Mon Sep 17 00:00:00 2001
From: Nick White <git@njw.name>
Date: Mon, 13 May 2019 16:54:15 +0100
Subject: Use the simplified findbestedge function, and simplify code
---
cleanup/main.go | 47 ++++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 42 insertions(+), 5 deletions(-)
(limited to 'cleanup')
diff --git a/cleanup/main.go b/cleanup/main.go
index bf94fcf..e0b66ce 100644
--- a/cleanup/main.go
+++ b/cleanup/main.go
@@ -1,5 +1,10 @@
package main
+// TODO: add minimum size variable (default ~30%?)
+// TODO: add tests
+// TODO: make into a small library
+// TODO: have the integral image specific stuff done by interface functions
+
import (
"flag"
"fmt"
@@ -43,9 +48,19 @@ func checkwindow(integral [][]uint64, x int, size int, thresh float64) bool {
return proportion <= thresh
}
-// cleanimg fills the sections of image not within the boundaries
+// returns the proportion of the given window that is black pixels
+func proportion(integral [][]uint64, x int, size int) float64 {
+ 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
+ return float64(area)/float64(sum) - 1
+}
+
+// wipesides 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 {
+func wipesides(img *image.Gray, lowedge int, highedge int) *image.Gray {
b := img.Bounds()
new := image.NewGray(b)
@@ -71,6 +86,28 @@ func cleanimg(img *image.Gray, lowedge int, highedge int) *image.Gray {
return new
}
+// findbestedge goes through every vertical line from x to x+w to
+// find the one with the lowest proportion of black pixels.
+func findbestedge(integral [][]uint64, x int, w int) int {
+ var bestx int
+ var best float64
+
+ if w == 1 {
+ return x
+ }
+
+ right := x + w
+ for ; x < right; x++ {
+ prop := proportion(integral, x, 1)
+ if prop > best {
+ best = prop
+ bestx = x
+ }
+ }
+
+ return bestx
+}
+
// findedges finds the edges of the main content, by moving a window of wsize
// from the middle of the image to the left and right, stopping when it reaches
// a point at which there is a lower proportion of black pixels than thresh.
@@ -80,14 +117,14 @@ func findedges(integral [][]uint64, wsize int, thresh float64) (int, int) {
for x := maxx / 2; x < maxx-wsize; x++ {
if checkwindow(integral, x, wsize, thresh) {
- highedge = x + (wsize / 2)
+ highedge = findbestedge(integral, x, wsize)
break
}
}
for x := maxx / 2; x > 0; x-- {
if checkwindow(integral, x, wsize, thresh) {
- lowedge = x - (wsize / 2)
+ lowedge = findbestedge(integral, x, wsize)
break
}
}
@@ -125,7 +162,7 @@ func main() {
lowedge, highedge := findedges(integral, *wsize, *thresh)
- clean := cleanimg(gray, lowedge, highedge)
+ clean := wipesides(gray, lowedge, highedge)
f, err = os.Create(flag.Arg(1))
if err != nil {
--
cgit v1.2.1-24-ge1ad