find barcode using opencv

app/modules/cv-wrapper.js

@@ -0,0 +1,80 @@
+import cv from 'cv'; 
+
+export default class CvWrapper {
+  findBarcode(el) { 
+    this.initVariables(el);
+
+    cv.cvtColor(this.src, this.src, cv.COLOR_RGBA2GRAY, 0);
+
+    cv.Sobel(this.src, this.gradX, cv.CV_32F, 1, 0, -1)
+    cv.Sobel(this.src, this.gradY, cv.CV_32F, 0, 1, -1)
+    cv.subtract(this.gradX, this.gradY, this.src);
+    cv.convertScaleAbs(this.src, this.src);
+   
+    cv.blur(this.src, this.src, this.ksize);
+    cv.threshold(this.src, this.src, 210, 255, cv.THRESH_BINARY);
+    
+    this.M = cv.getStructuringElement(cv.MORPH_RECT, this.ksize2);
+    cv.morphologyEx(this.src, this.src, cv.MORPH_CLOSE, this.M)
+
+    cv.erode(this.src, this.src, this.M2, this.anchor, 7);
+    cv.dilate(this.src, this.src, this.M2, this.anchor, 2);
+
+    cv.findContours(this.src, this.contours, this.hierarchy, cv.RETR_EXTERNAL, cv.CHAIN_APPROX_SIMPLE);
+    let biggest = 0;
+    let index;
+    for (let i = 0; i < this.contours.size(); i++) {
+      let cnt = this.contours.get(i);
+      let area = cv.contourArea(cnt, false);
+      if (area > biggest) {
+        biggest = area;
+        this.contour = cnt;
+        index = i
+      }
+    }
+
+    let rect = cv.boundingRect(this.contour);
+    let rectangleColor = new cv.Scalar(255, 255, 255);
+    let point1 = new cv.Point(rect.x, rect.y);
+    let point2 = new cv.Point(rect.x + rect.width, rect.y + rect.height);
+
+    this.dst = this.dst.roi(rect);
+
+    cv.rectangle(this.preview, point1, point2, rectangleColor, 2, cv.LINE_AA, 0);
+    
+    cv.imshow('canvasOutput', this.dst);
+    cv.imshow('canvasPreview', this.preview);
+
+    this.cleanUpVariable();
+  }
+
+  initVariables(el) {
+    this.src = cv.imread(el);
+    this.preview = this.src.clone();
+    this.dst = this.src.clone();
+    this.dsize = new cv.Size(300, 300);
+    this.gradX = new cv.Mat();
+    this.gradY = new cv.Mat();
+    this.M = new cv.Mat();
+    this.ksize = new cv.Size(3, 3);
+    this.ksize2 = new cv.Size(21, 7);
+    this.contours = new cv.MatVector();
+    this.contour = new cv.Mat();
+    this.hierarchy = new cv.Mat();
+    this.M2 = cv.Mat.ones(5, 5, cv.CV_32F);
+    this.anchor = new cv.Point(-1, -1);
+  }
+
+  cleanUpVariable() {
+    this.src.delete(); 
+    this.dst.delete(); 
+    this.gradX.delete(); 
+    this.gradY.delete();
+    this.M.delete(); 
+    this.M2.delete(); 
+    this.contours.delete(); 
+    this.hierarchy.delete();
+    this.contour.delete(); 
+    this.preview.delete(); 
+  }
+}