OpenCV 在 Java 中按区域对轮廓进行排序 [英] OpenCV Sorting Contours by Area in Java

问题描述

这是我第一次使用 OpenCV，我无法找出按区域对轮廓进行排序的方法.我正在寻找两个最大的区域.目前我有:

This is my first time working with OpenCV, I am having trouble figuring out a method to sort the contours by area. I am looking for the two largest areas. Currently I have:

 List<MatOfPoint> contours = new ArrayList<MatOfPoint>();
 Imgproc.findContours(MatOut, contours, new Mat(), Imgproc.RETR_LIST, Imgproc.CHAIN_APPROX_SIMPLE);

推荐答案

For Java 8+

For Java 8+

//finding max area
Optional<MatOfPoint> largest = contours.stream().max(new Comparator<MatOfPoint>() {
        public int compare(MatOfPoint c1, MatOfPoint c2) {          
            return (int) (Imgproc.contourArea(c1)- Imgproc.contourArea(c2));
        }
    });
// sorting 
contours.sort(new Comparator<MatOfPoint>() {
        public int compare(MatOfPoint c1, MatOfPoint c2) {          
            return (int) (Imgproc.contourArea(c1)- Imgproc.contourArea(c2));
        }
    });

对于 Java 7，使用 Collections.sort 和相同的比较器并获取第一个元素.

For Java 7 use Collections.sort with same comparator and get the first element.

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