如何在 pyplot 中绘制坐标列表？

Question

我提取了图像的边缘，以便将它们用作坐标来生成具有图像边缘的图形。但是当尝试使用 plot 或 scatter 方法时，每个函数分别不显示任何内容和错误。

import cv2 as cv
import numpy as np
from matplotlib import pyplot as grafico

def bwareaopen(img, min_size, connectivity=8):
    """Remove small objects from binary image (partial approximation of 
    bwareaopen in Matlab for 2D images).

    Args:
        img: a binary image (dtype=uint8) to remove small objects from
        min_size: the maximum size of small objects to be removed
        connectivity: Pixel connectivity; either 4 (connected via edges) or 8 (connected via edges and corners).

    Returns:
        the binary image with small objects removed
    """

    # Find all connected components (called here "labels")
    num_labels, labels, stats, centroids = cv.connectedComponentsWithStats(
        img, connectivity=connectivity)
    
    # check size of all connected components (area in pixels)
    for i in range(num_labels):
        label_size = stats[i, cv.CC_STAT_AREA]
        
        # remove connected components smaller than min_size
        if label_size < min_size:
            img[labels == i] = 0
            
    return img


# abre a img com opencv
path_img = 'input.jpeg'
img = cv.imread(path_img)

# converte imagem p/ tons de cinza
gray = cv.cvtColor(img, cv.COLOR_BGR2GRAY)

# calculo de de thresholding com otsu
ret, level = cv.threshold(gray, 0, 255, cv.THRESH_BINARY | cv.THRESH_OTSU);

# converte imagem p/ preto e branco
_, bw_img = cv.threshold(gray, 127, 255, cv.THRESH_BINARY)
bw_img - bwareaopen(bw_img, 50)

# detector de bordas
bw_img_edges = cv.Canny(bw_img, 400, 800)
#cv.imwrite('edge.jpeg', bw_img_edges)

# checando o resultado do Canny
cv.imshow("Edges", bw_img_edges)
cv.waitKey(0)

# detecta as dimensoes da imagem em uma variavel
bw_img_shape = bw_img_edges.shape

# detecta onde ha bordas na imagem e captura sua posicao
# lista onde as coordenadas ficarao salvas
coordenadas = []
# dimensoes da imagem em variaveis
height, width = img.shape[:2]

for i in range(1, height):
    for j in range(1, width):
       if(bw_img_edges[i,j]==255):
          coordenadas.append([i,j])

# coloca as coordenadas no pyplot(grafico)
####grafico.plot(coordenadas)####

如何在图表上绘制列表“coordenadas”中的坐标？

Answer 1

你得到的错误会更容易。这可以解决问题：

coords = np.array(coordenadas)
plt.scatter(coords[:,0], coords[:,1])

如何在 pyplot 中绘制坐标列表？

How can I plot a list of coordinates in pyplot?

python

graphics

opencv

matplotlib

computer-vision