opencv - 如何从 opencv js 中的 findContours() 访问数据

Question

按照这个 JS 教程https://docs.opencv.org/master/d5/daa/tutorial_js_contours_begin.html

// where data is a Uint8 image array
const cv_formatted_mat = new cv.matFromArray(height, width,
  cv.CV_8UC1, data);

cv.findContours(  cv_formatted_mat, contours, hierarchy, ...)

console.log(hierarchy.size())
// returns a number eg 12

console.log(hierarchy[0])  
// undefined
// expected some value since .size() returns a number

具有值 (MatVector) 并显示大小 (12) 但选择元素未定义的层次结构示例

console.log("hierarchy", hierarchy, hierarchy[0], hierarchy.size())
console.log("contours", contours, contours[0], contours.size())

我们如何访问层次结构？

Answer 1

有一种.get()方法。

let contour = contours.get(0)
console.log("contour", contour)
let Moments = cv.moments(contour, false)
console.log(Moments)

来自https://docs.opencv.org/3.4/dc/dcf/tutorial_js_contour_features.html