15、OpenCV Python 轮廓发现

__author__ = "WSX"
import cv2 as cv
import numpy as np
# 基于拓扑结构来发现和绘制（边缘提取）
# cv.findContours() 发现轮廓
# cv.drawContours()  绘制轮廓
# 使用梯度 ，不需要阈值了就

def edge_demo(image):
    blurred = cv.GaussianBlur(image, (3, 3), 0)
    gray = cv.cvtColor(blurred, cv.COLOR_BGR2GRAY)
    # X Gradient
    xgrad = cv.Sobel(gray, cv.CV_16SC1, 1, 0)
    # Y Gradient
    ygrad = cv.Sobel(gray, cv.CV_16SC1, 0, 1)
    #edge
    #edge_output = cv.Canny(xgrad, ygrad, 50, 150)
    edge_output = cv.Canny(gray, 30, 100)
    cv.imshow("Canny Edge", edge_output)
    return edge_output


def contours_demo(image):
    """dst = cv.GaussianBlur(image, (3, 3), 0)
    gray = cv.cvtColor(dst, cv.COLOR_BGR2GRAY)
    ret, binary = cv.threshold(gray, 0, 255, cv.THRESH_BINARY | cv.THRESH_OTSU)
    cv.imshow("binary image", binary)"""
    binary = edge_demo(image)

    cloneImage, contours, heriachy = cv.findContours(binary, cv.RETR_EXTERNAL, cv.CHAIN_APPROX_SIMPLE)
    # cv.RETR_EXTERNAL最大轮廓  CHAIN_APPROX_SIMPLE简单的
    #contours 放轮廓          heriachy层次信息
    for i, contour in enumerate(contours):
        cv.drawContours(image, contours, i, (0, 0, 255), 2)
        #绘制(0, 0, 255)颜色   2 为宽度       若为-1 则填充轮廓
        approxCurve = cv.approxPolyDP(contour, 4, True)
        if approxCurve.shape[0] > 6:
            cv.drawContours(image, contours, i, (0, 255, 255), 2)
        if approxCurve.shape[0] == 4:
            cv.drawContours(image, contours, i, (255, 255, 0), 2)
        print(approxCurve.shape[0])
        print(i)
    cv.imshow("detect contours", image)

def main():
    img = cv.imread("1.JPG")
    cv.namedWindow("Show", cv.WINDOW_AUTOSIZE)
    cv.imshow("Show", img)

    contours_demo(img)
    cv.waitKey(0)
    cv.destroyAllWindows()

main()