func processImage(input *cv.IplImage) (*cv.IplImage, []Rect) {
storage := cv.NewMemStorage(0)
defer storage.Release()
hsv := cv.NewImage(input.Size(), 8, 3)
defer hsv.Release()
sat := cv.NewImage(input.Size(), 8, 1)
defer sat.Release()
val := cv.NewImage(input.Size(), 8, 1)
defer val.Release()
threshSat := cv.NewImage(input.Size(), 8, 1)
defer threshSat.Release()
threshVal := cv.NewImage(input.Size(), 8, 1)
defer threshVal.Release()
thresh := cv.NewImage(input.Size(), 8, 1)
cv.CvtColor(input, hsv, cv.BGR2HSV)
cv.Split(hsv, nil, sat, nil, nil)
cv.Split(hsv, nil, nil, val, nil)
cv.Threshold(sat, threshSat, 70, 255, cv.THRESH_BINARY)
//cv.ShowImage(satWindowName, threshSat)
cv.Threshold(val, threshVal, 70, 255, cv.THRESH_BINARY_INV)
//cv.ShowImage(valWindowName, threshVal)
cv.And(threshVal, threshSat, thresh, nil)
cv.Dilate(thresh, thresh, nil, 1)
cv.Erode(thresh, thresh, nil, 1)
rects := make([]Rect, 0)
threshClone := thresh.Clone()
defer threshClone.Release()
contour, _ := cv.FindContours(threshClone, storage, cv.RETR_LIST, cv.CHAIN_APPROX_SIMPLE, cv.Point{})
for ; !contour.IsZero(); contour = contour.Next() {
result := cv.ApproxPoly(contour, storage, cv.POLY_APPROX_DP, cv.ContourPerimeter(contour)*0.02, 0)
if result.Len() != 4 || cv.ContourArea(result, cv.WHOLE_SEQ, false) < 1000 || !cv.CheckContourConvexity(result) {
continue
}
var r Rect
for i := 0; i < 4; i++ {
r[i] = result.PointAt(i)
}
rects = append(rects, r)
}
return thresh, rects
}
func drawRectangles(img *cv.IplImage, rects [][4]cv.Point) {
cpy := img.Clone()
defer cpy.Release()
for _, r := range rects {
points := r[:]
cv.PolyLine(cpy, [][]cv.Point{points}, true, cv.Scalar{0.0, 255.0, 0.0, 0.0}, 3, cv.AA, 0)
}
cv.ShowImage(windowName, cpy)
}
func findRectangles(img *cv.IplImage) [][4]cv.Point {
storage := cv.NewMemStorage(0)
defer storage.Release()
sz := cv.Size{img.Width &^ 1, img.Height &^ 1}
timg := img.Clone()
defer timg.Release()
gray := cv.NewImage(sz, 8, 1)
defer gray.Release()
pyr := cv.NewImage(cv.Size{sz.Width / 2, sz.Height / 2}, 8, 3)
defer pyr.Release()
rects := make([][4]cv.Point, 0)
timg.SetROI(cv.Rect{0, 0, sz.Width, sz.Height})
cv.PyrDown(timg, pyr, cv.GAUSSIAN_5x5)
cv.PyrUp(timg, pyr, cv.GAUSSIAN_5x5)
tgray := cv.NewImage(sz, 8, 1)
defer tgray.Release()
for channel := 1; channel <= 3; channel++ {
timg.SetCOI(channel)
cv.Copy(timg, tgray, nil)
cv.Threshold(tgray, gray, lowThreshold, highThreshold, cv.THRESH_BINARY)
cv.Dilate(gray, gray, nil, 10)
cv.Erode(gray, gray, nil, 8)
contour, _ := cv.FindContours(gray, storage, cv.RETR_LIST, cv.CHAIN_APPROX_SIMPLE, cv.Point{0, 0})
for ; !contour.IsZero(); contour = contour.Next() {
result := cv.ApproxPoly(contour, storage, cv.POLY_APPROX_DP, cv.ContourPerimeter(contour)*0.02, 0)
if result.Len() != 4 || cv.ContourArea(result, cv.WHOLE_SEQ, false) < 1000 || !cv.CheckContourConvexity(result) {
continue
}
var r [4]cv.Point
for i := 0; i < 4; i++ {
r[i] = result.PointAt(i)
}
s := 0.0
// TODO: Check this boundary
for i := 2; i < 5; i++ {
t := math.Abs(angle(result.PointAt(i%4), result.PointAt((i-2)%4), result.PointAt((i-1)%4)))
if t > s {
s = t
}
}
// originally 0.3 for strict 90 degrees, may need to increase slightly
if s < 0.4 {
points := r
sort.Sort(ByY(points[:]))
distance := (points[2].Y+points[3].Y)/2 - (points[0].Y+points[1].Y)/2
fmt.Println("average height: ", distance)
rects = append(rects, r)
}
}
}
return rects
}