Added functions:

- FindContours
- DrawContours
- Set
- EqualizeHist

and associated constants

opencv/cv.go

@@ -23,7 +23,11 @@ const (
 	CV_BGR2BGRA  = C.CV_BGR2BGRA
 	CV_RGBA2BGRA = C.CV_RGBA2BGRA
 
+	CV_BLUR_NO_SCALE = C.CV_BLUR_NO_SCALE
 	CV_BLUR          = C.CV_BLUR
+	CV_GAUSSIAN      = C.CV_GAUSSIAN
+	CV_MEDIAN        = C.CV_MEDIAN
+	CV_BILATERAL     = C.CV_BILATERAL
 
 	CV_8U  = C.CV_8U
 	CV_8S  = C.CV_8S

opencv/cxcore.go

@@ -113,6 +113,11 @@ func (img *IplImage) GetROI() Rect {
 	return Rect(r)
 }
 
+/* Equalizes the histogram of a grayscale image */
+func (img *IplImage) EqualizeHist(dest *IplImage) {
+	C.cvEqualizeHist(unsafe.Pointer(img), unsafe.Pointer(dest))
+}
+
 /*
 Reshape changes shape of the image without copying data. A value of `0` means
 that channels or rows remain unchanged.
@@ -142,6 +147,11 @@ func (img *IplImage) Get3D(x, y, z int) Scalar {
 	return Scalar(ret)
 }
 
+/* Sets every element of an array to a given value. */
+func (img *IplImage) Set(value Scalar) {
+	C.cvSet(unsafe.Pointer(img), (C.CvScalar)(value), nil)
+}
+
 /* Set1D sets a particular element in the image */
 func (img *IplImage) Set1D(x int, value Scalar) {
 	C.cvSet1D(unsafe.Pointer(img), C.int(x), (C.CvScalar)(value))
@@ -531,6 +541,13 @@ func Not(src, dst *IplImage) {
 /****************************************************************************************\
 *                              Dynamic data structures                        *
 \****************************************************************************************/
+func (seq *Seq) Release() {
+	C.cvReleaseMemStorage(&seq.storage)
+}
+
+func (seq *Seq) Total() int {
+	return (int)(seq.total)
+}
 
 /****************************************************************************************\
 *                                     Drawing                                 *

opencv/imgproc.go

@@ -54,10 +54,12 @@ func Crop(src *IplImage, x, y, width, height int) *IplImage {
 }
 
 func CreateContourType() *ContourType {
-	return &ContourType{CV_RETR_EXTERNAL, CV_CHAIN_APPROX_SIMPLE, Point{0, 0}}
+	return &ContourType{mode: CV_RETR_EXTERNAL, method: CV_CHAIN_APPROX_SIMPLE, offset: Point{0, 0}}
 }
 
-func (this *ContourType) FindContours(image *IplImage) []*Contour {
+/* Returns a Seq of countours in an image, detected according to the parameters in ContourType.
+   Caller must Release() the Seq returned */
+func (this *ContourType) FindContours(image *IplImage) *Seq {
 	storage := C.cvCreateMemStorage(0)
 	header_size := (C.size_t)(unsafe.Sizeof(C.CvContour{}))
 	var seq *C.CvSeq
@@ -70,14 +72,18 @@ func (this *ContourType) FindContours(image *IplImage) []*Contour {
 		this.method,
 		C.cvPoint(C.int(this.offset.X), C.int(this.offset.Y)))
 
-	var contours []*Contour
-	for i := 0; i < (int)(seq.total); i++ {
-		contour := (*Contour)((*_Ctype_CvContour)(unsafe.Pointer(C.cvGetSeqElem(seq, C.int(i)))))
-		contours = append(contours, contour)
-	}
-
-	storage_c := (*C.CvMemStorage)(storage)
-	C.cvReleaseMemStorage(&storage_c)
-
-	return contours
+	return (*Seq)(seq)
+}
+
+//cvDrawContours(CvArr* img, CvSeq* contour, CvScalar externalColor, CvScalar holeColor, int maxLevel, int thickness=1, int lineType=8
+func DrawContours(image *IplImage, contours *Seq, externalColor, holeColor Scalar, maxLevel, thickness, lineType int, offset Point) {
+	C.cvDrawContours(
+		unsafe.Pointer(image),
+		(*C.CvSeq)(contours),
+		(C.CvScalar)(externalColor),
+		(C.CvScalar)(holeColor),
+		C.int(maxLevel),
+		C.int(thickness),
+		C.int(lineType),
+		C.cvPoint(C.int(offset.X), C.int(offset.Y)))
 }

opencv/imgproc_test.go

@@ -1,10 +1,11 @@
 package opencv
 
 import (
-	"log"
 	"path"
 	"runtime"
+	"os"
 	"testing"
+	"syscall"
 )
 
 func TestResize(t *testing.T) {
@@ -59,7 +60,7 @@ func TestCrop(t *testing.T) {
 
 func TestFindContours(t *testing.T) {
 	_, currentfile, _, _ := runtime.Caller(0)
-	filename := path.Join(path.Dir(currentfile), "../images/shapes.png")
+	filename := path.Join(path.Dir(currentfile), "../images/pic5.png")
 
 	image := LoadImage(filename)
 	if image == nil {
@@ -67,13 +68,47 @@ func TestFindContours(t *testing.T) {
 	}
 	defer image.Release()
 
-	grayscale_image := CreateImage(image.Width(), image.Height(), IPL_DEPTH_8U, 1)
-	CvtColor(image, grayscale_image, CV_BGR2GRAY)
-	defer grayscale_image.Release()
+	grayscale := CreateImage(image.Width(), image.Height(), IPL_DEPTH_8U, 1)
+	CvtColor(image, grayscale, CV_BGR2GRAY)
+	defer grayscale.Release()
 
-	cType := CreateContourType()
-	contours := cType.FindContours(grayscale_image)
-	for i, c := range contours {
-		log.Printf("Contour[%v] = %v", i, c)
+
+	edges := CreateImage(grayscale.Width(), grayscale.Height(), grayscale.Depth(), grayscale.Channels())
+	defer edges.Release()
+	Canny(grayscale, edges, 50, 200, 3)
+
+	contourType := CreateContourType()
+	seq := contourType.FindContours(edges)
+	defer seq.Release()
+
+	contours := CreateImage(grayscale.Width(), grayscale.Height(), grayscale.Depth(), grayscale.Channels())
+	white := NewScalar(255, 255, 255, 0)
+	contours.Set(white)
+
+	black := NewScalar(0, 0, 0, 0)
+	red := NewScalar(0, 255, 0, 0)
+
+	for ; seq != nil; seq = (*Seq)(seq.h_next) {
+		DrawContours(contours, seq, red, black, 0, 2, 8, Point{0, 0})
 	}
+
+	filename = path.Join(path.Dir(currentfile), "../images/pic5_contours.png")
+	// Uncomment this code to create the test image "../images/shapes_contours.png"
+	// It is part of the repo, and what this test compares against
+	//
+	//SaveImage(filename), contours, 0)
+
+	tempfilename := path.Join(os.TempDir(), "pic5_contours.png")
+	defer syscall.Unlink(tempfilename)
+	SaveImage(tempfilename, contours, 0)
+
+	// Compare actual image with expected image
+	same, err := BinaryCompare(filename, tempfilename)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !same {
+		t.Error("Expected contour file != actual contour file")
+	}
+
 }