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
}
