本文在边缘检测的基础上继续，即将上文边缘检测的结果（矩阵）输入，然后进一步发现轮廓并绘制
这里先将opencv库的加载设置为类的静态代码块，在相关方法代码体里面不再声明
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| static {
try {
NativeLoader.loadLibrary(Core.NATIVE_LIBRARY_NAME);
} catch (IOException e) {
e.printStackTrace();
}
}
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下面是轮廓绘制的相关方法
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static List<MatOfPoint> find_contours(Mat image, boolean onBlank) {
Mat imageBW = new Mat();
Imgproc.cvtColor(image, imageBW, Imgproc.COLOR_BGR2GRAY);
Imgproc.Canny(imageBW,imageBW,100.0,300.0,3, true);
List<MatOfPoint> contours = new ArrayList<MatOfPoint>();
Imgproc.findContours(imageBW, contours, new Mat(), Imgproc.RETR_EXTERNAL, Imgproc.CHAIN_APPROX_NONE);
return contours;
}
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| static Scalar BLACK = new Scalar(0,0,0) ;
static Mat draw_contours(Mat originalMat, List<MatOfPoint> contours, int thickness) {
Mat target =
new Mat(originalMat.height(), originalMat.width(), CvType.CV_8UC3, WHITE);
for (int i = 0; i < contours.size(); i++)
Imgproc.drawContours(target, contours, i, BLACK, thickness);
return target;
}
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public static void main(String[] args) {
Mat kittens = imread("images/three_black_kittens.jpg");
List<MatOfPoint> contours = find_contours(kittens, true);
Mat target = draw_contours(kittens, contours, 7);
imwrite("output/kittens-contours-7.png", target);
Mat masked = mask_on_bg(target, "images/light-blue-gradient.jpg");
imwrite("output/kittens-masked.png", masked);
target = draw_contours(kittens, contours, 3);
imwrite("output/kittens-contours-3.png", target);
}
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原图
处理后
下面是使用掩模的输出
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| static Mat mask_on_bg(Mat mask, String backgroundFilePath) {
Mat target = new Mat(mask.height(),mask.width(),CvType.CV_8UC3,WHITE);
Mat bg = imread(backgroundFilePath);
Imgproc.resize(bg, bg, target.size());
bg.copyTo(target, mask);
return target;
}
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