Merge pull request #339 from jspdown/master

Add GetStructuringElement, kernel argument for Erode and Dilate

examples/remove-lines.js

@@ -0,0 +1,30 @@
+var cv = require('../lib/opencv');
+
+// Load the image
+cv.readImage('./files/note.png', function(err, im) {
+  if (err) {
+    throw err;
+  }
+  if (im.width() < 1 || im.height() < 1) {
+    throw new Error('Image has no size');
+  }
+
+  im.cvtColor('CV_BGR2GRAY');
+  var bw = im.adaptiveThreshold(255, 0, 0, 15, 2);
+  bw.bitwiseNot(bw);
+
+  var vertical = bw.clone();
+
+  var verticalsize = vertical.size()[0] / 30;
+  var verticalStructure = cv.imgproc.getStructuringElement(1, [1, verticalsize]);
+
+  // Apply morphology operations
+  vertical.erode(1, verticalStructure);
+  vertical.dilate(1, verticalStructure);
+
+  vertical.bitwiseNot(vertical);
+  vertical.gaussianBlur([3, 3]);
+
+  // Save output image
+  vertical.save('./tmp/note.png');
+});

src/ImgProc.cc

@@ -9,6 +9,7 @@ void ImgProc::Init(Local<Object> target) {
   Nan::SetMethod(obj, "undistort", Undistort);
   Nan::SetMethod(obj, "initUndistortRectifyMap", InitUndistortRectifyMap);
   Nan::SetMethod(obj, "remap", Remap);
+  Nan::SetMethod(obj, "getStructuringElement", GetStructuringElement);
 
   target->Set(Nan::New("imgproc").ToLocalChecked(), obj);
 }
@@ -157,3 +158,45 @@ NAN_METHOD(ImgProc::Remap) {
     return;
   }
 }
+
+// cv::getStructuringElement
+NAN_METHOD(ImgProc::GetStructuringElement) {
+  Nan::EscapableHandleScope scope;
+
+  try {
+    // Get the arguments
+
+    if (info.Length() != 2) {
+      Nan::ThrowTypeError("Invalid number of arguments");
+    }
+
+    // Arg 0 is the element shape
+    if (!info[0]->IsNumber()) {
+      JSTHROW_TYPE("'shape' argument must be a number");
+    }
+    int shape = info[0]->NumberValue();
+
+    // Arg 1 is the size of the structuring element
+    cv::Size ksize;
+    if (!info[1]->IsArray()) {
+      JSTHROW_TYPE("'ksize' argument must be a 2 double array");
+    }
+    Local<Object> v8sz = info[1]->ToObject();
+    ksize = cv::Size(v8sz->Get(0)->IntegerValue(), v8sz->Get(1)->IntegerValue());
+
+    // GetStructuringElement
+    cv::Mat mat = cv::getStructuringElement(shape, ksize);
+
+    // Wrap the output image
+    Local<Object> outMatrixWrap = Nan::New(Matrix::constructor)->GetFunction()->NewInstance();
+    Matrix *outMatrix = ObjectWrap::Unwrap<Matrix>(outMatrixWrap);
+    outMatrix->mat = mat;
+
+    // Return the image
+    info.GetReturnValue().Set(outMatrixWrap);
+  } catch (cv::Exception &e) {
+    const char *err_msg = e.what();
+    JSTHROW(err_msg);
+    return;
+  }
+}

src/ImgProc.h

@@ -12,6 +12,7 @@ class ImgProc: public Nan::ObjectWrap {
   static NAN_METHOD(Undistort);
   static NAN_METHOD(InitUndistortRectifyMap);
   static NAN_METHOD(Remap);
+  static NAN_METHOD(GetStructuringElement);
 };
 
 #endif

src/Matrix.cc

@@ -1341,7 +1341,13 @@ NAN_METHOD(Matrix::Dilate) {
   Matrix *self = Nan::ObjectWrap::Unwrap<Matrix>(info.This());
   int niters = info[0]->NumberValue();
 
-  cv::dilate(self->mat, self->mat, cv::Mat(), cv::Point(-1, -1), niters);
+  cv::Mat kernel = cv::Mat();
+  if (info.Length() == 2) {
+    Matrix *kernelMatrix = Nan::ObjectWrap::Unwrap<Matrix>(info[1]->ToObject());
+    kernel = kernelMatrix->mat;
+  }
+
+  cv::dilate(self->mat, self->mat, kernel, cv::Point(-1, -1), niters);
 
   info.GetReturnValue().Set(Nan::Null());
 }
@@ -1352,7 +1358,12 @@ NAN_METHOD(Matrix::Erode) {
   Matrix *self = Nan::ObjectWrap::Unwrap<Matrix>(info.This());
   int niters = info[0]->NumberValue();
 
-  cv::erode(self->mat, self->mat, cv::Mat(), cv::Point(-1, -1), niters);
+  cv::Mat kernel = cv::Mat();
+  if (info.Length() == 2) {
+    Matrix *kernelMatrix = Nan::ObjectWrap::Unwrap<Matrix>(info[1]->ToObject());
+    kernel = kernelMatrix->mat;
+  }
+  cv::erode(self->mat, self->mat, kernel, cv::Point(-1, -1), niters);
 
   info.GetReturnValue().Set(Nan::Null());
 }