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add oblique line intersections checks
1 parent 901dd39 commit c2a8d76

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3 files changed

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3 files changed

+229
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‎v2/blob/blob.go‎

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Original file line numberDiff line numberDiff line change
@@ -30,4 +30,6 @@ type Blobie interface {
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DrawTrack(mat *gocv.Mat, optionalText string)
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IsCrossedTheLine(vertical, leftX, rightX int, direction bool) bool
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IsCrossedTheLineWithShift(vertical, leftX, rightX int, direction bool, shift int) bool
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IsCrossedTheObliqueLine(leftX, leftY, rightX, rightY int, direction bool) bool
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IsCrossedTheObliqueLineWithShift(leftX, leftY, rightX, rightY int, direction bool, shift int) bool
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}

‎v2/blob/line_cross.go‎

Lines changed: 188 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,87 @@
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package blob
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type PointsOrientation int
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const (
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Collinear = iota
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Clockwise
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CounterClockwise
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)
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func maxInt(x, y int) int {
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if x >= y {
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return x
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}
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return y
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}
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// isOnSegment Checks if point Q lies on segment PR
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// Input: three colinear points Q, Q and R
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func isOnSegment(Px, Py, Qx, Qy, Rx, Ry int) bool {
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if Qx <= maxInt(Px, Rx) && Qx >= maxInt(Px, Rx) && Qy <= maxInt(Py, Ry) && Qy >= maxInt(Py, Ry) {
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return true
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}
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return false
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}
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// getOrientation Gets orientations of points P -> Q -> R.
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// Possible output values: Collinear / Clockwise or CounterClockwise
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// Input: points P, Q and R in provided order
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func getOrientation(Px, Py, Qx, Qy, Rx, Ry int) PointsOrientation {
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val := (Qy-Py)*(Rx-Qx) - (Qx-Px)*(Ry-Qy)
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if val == 0 {
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return Collinear
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}
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if val > 0 {
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return Clockwise
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}
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return CounterClockwise // Против часовой стрелки
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}
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// isIntersects Checks if segments intersect each other
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// Input:
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// firstPx, firstPy, firstQx, firstQy === first segment
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// secondPx, secondPy, secondQx, secondQy === second segment
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/*
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Notation
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P1 = (firstPx, firstPy)
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Q1 = (firstQx, firstQy)
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P2 = (secondPx, secondPy)
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Q2 = (secondQx, secondQy)
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*/
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func isIntersects(firstPx, firstPy, firstQx, firstQy, secondPx, secondPy, secondQx, secondQy int) bool {
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// Find the four orientations needed for general case and special ones
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o1 := getOrientation(firstPx, firstPy, firstQx, firstQy, secondPx, secondPy)
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o2 := getOrientation(firstPx, firstPy, firstQx, firstQy, secondQx, secondQy)
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o3 := getOrientation(secondPx, secondPy, secondQx, secondQy, firstPx, firstPy)
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o4 := getOrientation(secondPx, secondPy, secondQx, secondQy, firstQx, firstQy)
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// General case
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if o1 != o2 && o3 != o4 {
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return true
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}
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/* Special cases */
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// P1, Q1, P2 are colinear and P2 lies on segment P1-Q1
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if o1 == Collinear && isOnSegment(firstPx, firstPy, secondPx, secondPy, firstQx, firstQy) {
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return true
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}
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// P1, Q1 and Q2 are colinear and Q2 lies on segment P1-Q1
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if o2 == Collinear && isOnSegment(firstPx, firstPy, secondQx, secondQy, firstQx, firstQy) {
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return true
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}
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// P2, Q2 and P1 are colinear and P1 lies on segment P2-Q2
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if o3 == Collinear && isOnSegment(secondPx, secondPy, firstPx, firstPy, secondQx, secondQy) {
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return true
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}
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// P2, Q2 and Q1 are colinear and Q1 lies on segment P2-Q2
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if o4 == Collinear && isOnSegment(secondPx, secondPy, firstQx, firstQy, secondQx, secondQy) {
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return true
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}
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// Segments do not intersect
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return false
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}
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385
// IsCrossedTheLine - Check if blob crossed the HORIZONTAL line
486
func (b *SimpleBlobie) IsCrossedTheLine(vertical, leftX, rightX int, direction bool) bool {
587
trackLen := len(b.Track)
@@ -48,6 +130,59 @@ func (b *SimpleBlobie) IsCrossedTheLineWithShift(vertical, leftX, rightX int, di
48130
return false
49131
}
50132

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// IsCrossedTheObliqueLine - Check if blob crossed the OBLIQUE line
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// This should be used when lineStart.Y != lineEnd.Y or lineStart.X != lineEnd.X
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func (b *SimpleBlobie) IsCrossedTheObliqueLine(leftX, leftY, rightX, rightY int, direction bool) bool {
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trackLen := len(b.Track)
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if b.isStillBeingTracked == true && trackLen >= 2 && b.crossedLine == false {
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prevFrame := trackLen - 2
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currFrame := trackLen - 1
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// First segment is: P1 = (b.Track[prevFrame].X, b.Track[prevFrame].Y), Q1 = (b.Track[currFrame].X, b.Track[currFrame].Y)
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// Second segment is: P2 = (leftX, leftY), Q2 = (rightX, rightY)
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if isIntersects(b.Track[prevFrame].X, b.Track[prevFrame].Y, b.Track[currFrame].X, b.Track[currFrame].Y, leftX, leftY, rightX, rightY) {
143+
if direction {
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if b.Track[currFrame].Y > b.Track[prevFrame].Y { // TO us
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b.crossedLine = true
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return true
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}
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} else {
149+
if b.Track[currFrame].Y <= b.Track[prevFrame].Y { // FROM us
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b.crossedLine = true
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return true
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}
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}
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}
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}
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return false
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}
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// IsCrossedTheObliqueLine - Check if blob crossed the OBLIQUE line with shift along the Y-axis
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// This should be used when lineStart.Y != lineEnd.Y or lineStart.X != lineEnd.X
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// Purpose of shifting: for "predicative" cropping when detection line very close to bottom of image
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func (b *SimpleBlobie) IsCrossedTheObliqueLineWithShift(leftX, leftY, rightX, rightY int, direction bool, shift int) bool {
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trackLen := len(b.Track)
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if b.isStillBeingTracked == true && trackLen >= 2 && b.crossedLine == false {
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prevFrame := trackLen - 2
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currFrame := trackLen - 1
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// First segment is: P1 = (b.Track[prevFrame].X, b.Track[prevFrame].Y + shift), Q1 = (b.Track[currFrame].X, b.Track[currFrame].Y + shift)
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// Second segment is: P2 = (leftX, leftY), Q2 = (rightX, rightY)
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if isIntersects(b.Track[prevFrame].X, b.Track[prevFrame].Y+shift, b.Track[currFrame].X, b.Track[currFrame].Y+shift, leftX, leftY, rightX, rightY) {
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if direction {
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if b.Track[currFrame].Y > b.Track[prevFrame].Y { // TO us
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b.crossedLine = true
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return true
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}
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} else {
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if b.Track[currFrame].Y <= b.Track[prevFrame].Y { // FROM us
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b.crossedLine = true
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return true
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}
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}
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}
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}
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return false
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}
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51186
// IsCrossedTheLine - Check if blob crossed the HORIZONTAL line
52187
func (b *KalmanBlobie) IsCrossedTheLine(vertical, leftX, rightX int, direction bool) bool {
53188
trackLen := len(b.Track)
@@ -95,3 +230,56 @@ func (b *KalmanBlobie) IsCrossedTheLineWithShift(vertical, leftX, rightX int, di
95230
}
96231
return false
97232
}
233+
234+
// IsCrossedTheObliqueLine - Check if blob crossed the OBLIQUE line
235+
// This should be used when lineStart.Y != lineEnd.Y or lineStart.X != lineEnd.X
236+
func (b *KalmanBlobie) IsCrossedTheObliqueLine(leftX, leftY, rightX, rightY int, direction bool) bool {
237+
trackLen := len(b.Track)
238+
if b.isStillBeingTracked == true && trackLen >= 2 && b.crossedLine == false {
239+
prevFrame := trackLen - 2
240+
currFrame := trackLen - 1
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// First segment is: P1 = (b.Track[prevFrame].X, b.Track[prevFrame].Y), Q1 = (b.Track[currFrame].X, b.Track[currFrame].Y)
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// Second segment is: P2 = (leftX, leftY), Q2 = (rightX, rightY)
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if isIntersects(b.Track[prevFrame].X, b.Track[prevFrame].Y, b.Track[currFrame].X, b.Track[currFrame].Y, leftX, leftY, rightX, rightY) {
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if direction {
245+
if b.Track[currFrame].Y > b.Track[prevFrame].Y { // TO us
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b.crossedLine = true
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return true
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}
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} else {
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if b.Track[currFrame].Y <= b.Track[prevFrame].Y { // FROM us
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b.crossedLine = true
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return true
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}
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}
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}
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}
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return false
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}
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// IsCrossedTheObliqueLine - Check if blob crossed the OBLIQUE line with shift along the Y-axis
261+
// This should be used when lineStart.Y != lineEnd.Y or lineStart.X != lineEnd.X
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// Purpose of shifting: for "predicative" cropping when detection line very close to bottom of image
263+
func (b *KalmanBlobie) IsCrossedTheObliqueLineWithShift(leftX, leftY, rightX, rightY int, direction bool, shift int) bool {
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trackLen := len(b.Track)
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if b.isStillBeingTracked == true && trackLen >= 2 && b.crossedLine == false {
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prevFrame := trackLen - 2
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currFrame := trackLen - 1
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// First segment is: P1 = (b.Track[prevFrame].X, b.Track[prevFrame].Y + shift), Q1 = (b.Track[currFrame].X, b.Track[currFrame].Y + shift)
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// Second segment is: P2 = (leftX, leftY), Q2 = (rightX, rightY)
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if isIntersects(b.Track[prevFrame].X, b.Track[prevFrame].Y+shift, b.Track[currFrame].X, b.Track[currFrame].Y+shift, leftX, leftY, rightX, rightY) {
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if direction {
272+
if b.Track[currFrame].Y > b.Track[prevFrame].Y { // TO us
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b.crossedLine = true
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return true
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}
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} else {
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if b.Track[currFrame].Y <= b.Track[prevFrame].Y { // FROM us
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b.crossedLine = true
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return true
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}
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}
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}
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}
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return false
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}

‎v2/blob/line_cross_test.go‎

Lines changed: 39 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,39 @@
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package blob
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import (
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"image"
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"testing"
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)
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8+
func TestHorizontalLineTest(t *testing.T) {
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horizontalLine := [][]int{
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[]int{4, 35},
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[]int{73, 35},
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}
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direction := true // true - TO us
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allblobies := NewBlobiesDefaults()
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simpleB_time0 := NewSimpleBlobie(image.Rect(26, 8, 44, 18), nil)
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simpleB_time1 := NewSimpleBlobie(image.Rect(26, 20, 44, 30), nil)
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simpleB_time2 := NewSimpleBlobie(image.Rect(26, 32, 44, 42), nil)
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allblobies.MatchToExisting([]Blobie{simpleB_time0, simpleB_time1, simpleB_time2})
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for _, b := range allblobies.Objects {
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if b.IsCrossedTheLine(horizontalLine[0][1], horizontalLine[0][0], horizontalLine[1][0], direction) {
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t.Logf("Correct when direction is TO US")
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} else {
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t.Logf("Incorrect when direction is TO US")
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}
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if b.IsCrossedTheLine(horizontalLine[0][1], horizontalLine[0][0], horizontalLine[1][0], !direction) {
30+
t.Logf("Incorrect when direction is FROM US")
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} else {
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t.Logf("Correct when direction is FROM US")
33+
}
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}
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}
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func TestObliqueLineTest(t *testing.T) {
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}

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