diff options
| -rw-r--r-- | integralimg.go | 18 |
1 files changed, 10 insertions, 8 deletions
diff --git a/integralimg.go b/integralimg.go index afdbebe..0ad734b 100644 --- a/integralimg.go +++ b/integralimg.go @@ -130,8 +130,8 @@ func (i Image) GetWindow(x, y, size int) Window { step := size / 2 minx, miny := 0, 0 - maxy := len(i)-1 - maxx := len(i[0])-1 + maxy := i.Bounds().Dy() - 1 + maxx := i.Bounds().Dx() - 1 if y > (step+1) { miny = y - step - 1 @@ -157,10 +157,11 @@ func (i SqImage) GetWindow(x, y, size int) Window { // GetVerticalWindow gets the values of the corners of a vertical // slice of an Integral Image, starting at x func (i Image) GetVerticalWindow(x, width int) Window { - maxy := len(i) - 1 + maxy := i.Bounds().Dy() - 1 + xbound := i.Bounds().Dx() - 1 maxx := x + width - if maxx > len(i[0])-1 { - maxx = len(i[0]) - 1 + if maxx > xbound { + maxx = xbound } return Window { i[0][x], i[0][maxx], i[maxy][x], i[maxy][maxx], width, maxy } @@ -188,9 +189,10 @@ func (w Window) Mean() float64 { // Proportion returns the proportion of pixels which are on func (w Window) Proportion() float64 { area := w.width * w.height - // divide by 255 as each on pixel has the value of 255 - sum := float64(w.Sum()) / 255 - return float64(area) / sum - 1 + // 1 << 16 - 1 as we're using Gray16, so for a binarised + // image then 1 << 16 - 1 = on + sum := float64(w.Sum()) / float64(1 << 16 - 1) + return float64(area) / float64(sum) - 1 } // MeanStdDevWindow calculates the mean and standard deviation of |