diff options
Diffstat (limited to 'integralimg')
| -rw-r--r-- | integralimg/integralimg.go | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/integralimg/integralimg.go b/integralimg/integralimg.go index 31f3e53..406ed61 100644 --- a/integralimg/integralimg.go +++ b/integralimg/integralimg.go @@ -89,7 +89,7 @@ func ToAllIntegralImg(img *image.Gray) WithSq { } -// GetWindow gets the values of the corners of a part of an +// GetWindow gets the values of the corners of a square part of an // Integral Image, plus the dimensions of the part, which can // be used to quickly calculate the mean of the area func (i I) GetWindow(x, y, size int) Window { @@ -116,6 +116,18 @@ func (i I) GetWindow(x, y, size int) Window { return Window { i[miny][minx], i[miny][maxx], i[maxy][minx], i[maxy][maxx], maxx-minx, maxy-miny} } +// GetVerticalWindow gets the values of the corners of a vertical +// slice of an Integral Image, starting at x +func (i I) GetVerticalWindow(x, width int) Window { + maxy := len(i) - 1 + maxx := x + width + if maxx > len(i[0])-1 { + maxx = len(i[0]) - 1 + } + + return Window { i[0][x], i[0][maxx], i[maxy][x], i[maxy][maxx], width, maxy } +} + // Sum returns the sum of all pixels in a Window func (w Window) Sum() uint64 { return w.bottomright + w.topleft - w.topright - w.bottomleft @@ -131,6 +143,14 @@ func (w Window) Mean() float64 { return float64(w.Sum()) / float64(w.Size()) } +// 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 +} + // MeanWindow calculates the mean value of a section of an Integral // Image func (i I) MeanWindow(x, y, size int) float64 { |