diff options
author | Nick White <git@njw.name> | 2019-05-13 17:31:26 +0100 |
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committer | Nick White <git@njw.name> | 2019-05-13 17:31:26 +0100 |
commit | a931288d3e813d069a2b6b010e5af4d73d308cf2 (patch) | |
tree | 390efabf90d484568e5ed12bd4ed0603e40dfd48 /cleanup/wipesides.go | |
parent | 1ac5035ef55d2f97d1b98a309d83a09a84395e07 (diff) |
Rename cleanup package to preproc, and add basic cmd version
Diffstat (limited to 'cleanup/wipesides.go')
-rw-r--r-- | cleanup/wipesides.go | 122 |
1 files changed, 0 insertions, 122 deletions
diff --git a/cleanup/wipesides.go b/cleanup/wipesides.go deleted file mode 100644 index ce3b374..0000000 --- a/cleanup/wipesides.go +++ /dev/null @@ -1,122 +0,0 @@ -package cleanup - -// TODO: add minimum size variable (default ~30%?) -// TODO: have the integral image specific stuff done by interface functions - -import ( - "image" - "image/color" -) - -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(area)/float64(sum) - 1 - return proportion <= thresh -} - -// 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 -} - -// 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. -func Findedges(integral [][]uint64, wsize int, thresh float64) (int, int) { - maxx := len(integral[0]) - 1 - var lowedge, highedge int = 0, maxx - - for x := maxx / 2; x < maxx-wsize; x++ { - if checkwindow(integral, x, wsize, thresh) { - highedge = findbestedge(integral, x, wsize) - break - } - } - - for x := maxx / 2; x > 0; x-- { - if checkwindow(integral, x, wsize, thresh) { - lowedge = findbestedge(integral, x, wsize) - break - } - } - - return lowedge, highedge -} - -// Wipesides fills the sections of image not within the boundaries -// of lowedge and highedge with white -func Wipesides(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 -} |