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| -rw-r--r-- | integralimg/integralimg.go | 173 |
1 files changed, 0 insertions, 173 deletions
diff --git a/integralimg/integralimg.go b/integralimg/integralimg.go deleted file mode 100644 index 5cfbaf3..0000000 --- a/integralimg/integralimg.go +++ /dev/null @@ -1,173 +0,0 @@ -// Copyright 2019 Nick White. -// Use of this source code is governed by the GPLv3 -// license that can be found in the LICENSE file. - -package integralimg - -import ( - "image" - "math" -) - -// I is the Integral Image -type I [][]uint64 - -// Sq contains an Integral Image and its Square -type WithSq struct { - Img I - Sq I -} - -// Window is a part of an Integral Image -type Window struct { - topleft uint64 - topright uint64 - bottomleft uint64 - bottomright uint64 - width int - height int -} - -// ToIntegralImg creates an integral image -func ToIntegralImg(img *image.Gray) I { - var integral I - var oldy, oldx, oldxy uint64 - b := img.Bounds() - for y := b.Min.Y; y < b.Max.Y; y++ { - newrow := []uint64{} - for x := b.Min.X; x < b.Max.X; x++ { - oldx, oldy, oldxy = 0, 0, 0 - if x > 0 { - oldx = newrow[x-1] - } - if y > 0 { - oldy = integral[y-1][x] - } - if x > 0 && y > 0 { - oldxy = integral[y-1][x-1] - } - pixel := uint64(img.GrayAt(x, y).Y) - i := pixel + oldx + oldy - oldxy - newrow = append(newrow, i) - } - integral = append(integral, newrow) - } - return integral -} - -// ToSqIntegralImg creates an integral image of the square of all -// pixel values -func ToSqIntegralImg(img *image.Gray) I { - var integral I - var oldy, oldx, oldxy uint64 - b := img.Bounds() - for y := b.Min.Y; y < b.Max.Y; y++ { - newrow := []uint64{} - for x := b.Min.X; x < b.Max.X; x++ { - oldx, oldy, oldxy = 0, 0, 0 - if x > 0 { - oldx = newrow[x-1] - } - if y > 0 { - oldy = integral[y-1][x] - } - if x > 0 && y > 0 { - oldxy = integral[y-1][x-1] - } - pixel := uint64(img.GrayAt(x, y).Y) - i := pixel * pixel + oldx + oldy - oldxy - newrow = append(newrow, i) - } - integral = append(integral, newrow) - } - return integral -} - -// ToAllIntegralImg creates a WithSq containing a regular and -// squared Integral Image -func ToAllIntegralImg(img *image.Gray) WithSq { - var s WithSq - s.Img = ToIntegralImg(img) - s.Sq = ToSqIntegralImg(img) - return s -} - - -// 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 { - step := size / 2 - - minx, miny := 0, 0 - maxy := len(i)-1 - maxx := len(i[0])-1 - - if y > (step+1) { - miny = y - step - 1 - } - if x > (step+1) { - minx = x - step - 1 - } - - if maxy > (y + step) { - maxy = y + step - } - if maxx > (x + step) { - maxx = x + step - } - - 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 -} - -// Size returns the total size of a Window -func (w Window) Size() int { - return w.width * w.height -} - -// Mean returns the average value of pixels in a Window -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 { - return i.GetWindow(x, y, size).Mean() -} - -// MeanStdDevWindow calculates the mean and standard deviation of -// a section on an Integral Image -func (i WithSq) MeanStdDevWindow(x, y, size int) (float64, float64) { - imean := i.Img.GetWindow(x, y, size).Mean() - smean := i.Sq.GetWindow(x, y, size).Mean() - - variance := smean - (imean * imean) - - return imean, math.Sqrt(variance) -} |