OpenCV：如何将旋转角度显示为图像上的文本？

编程问答 2022-08-12

问题描述

我的目标是创建一个在每个边界内包含旋转角度作为文本的图像。图像应包括彩色边界（我已确定）和每个边界内的角度值（我没有确定）。

PYTHON代码

import matplotlib.pyplot as plt
import cv2
import numpy as np
import csv


mask = cv2.imread('patch_mask.png')
mask = cv2.resize(mask,(400,400))
mask_gray = cv2.cvtColor(mask,cv2.COLOR_BGR2GRAY)
ret2,th2 = cv2.threshold(mask_gray,255,cv2.THRESH_BINARY + cv2.THRESH_OTSU)  # Otsu's 
method
image = cv2.imread('patch_image.png')
image_gray = cv2.cvtColor(image,cv2.COLOR_BGR2GRAY)
image_enhanced = cv2.equalizeHist(image_gray)

# process image
boundary_output = "/Desktop/mat2py/mask_boundary.png"
ellipse_output = "/Desktop/mat2py/ellipse.png"
colormap_output = "/Desktop/mat2py/colormap.png"
# im = cv2.imread("patch_mask.png")
imgray = cv2.cvtColor(mask,cv2.COLOR_BGR2GRAY)
ret,thresh = cv2.threshold(imgray,127,0)

# find contours in the binary image
contours,hierarchy = cv2.findContours(thresh,cv2.RETR_EXTERNAL,cv2.CHAIN_APPROX_NONE)
tmp = np.zeros_like(mask)
tmp2 = np.zeros_like(mask)
boundary = cv2.drawContours(tmp,contours,-1,(255,255),1)

# calculate moments and extract cell shape info
moment_dict = {}
for index,cnt in enumerate(contours):
    moment_dict[index] = cv2.moments(cnt)

# creating a csv file named coordinates
with open('/Desktop/mat2py/coordinates.csv','w',newline='') as newFile:
    newFileWriter = csv.writer(newFile)
    newFileWriter.writerow(
        ["Center_x","Center_y","(Center_x,Center_y)","(Major Axis,Minor Axis)","Rotation Angle"])

obj_properties = {}
for index,obj_moments in moment_dict.items():
    cx,cy = obj_moments['m10'] / obj_moments['m00'],obj_moments['m01'] / obj_moments['m00']
    ellipse = (x,y),(MA,ma),angle = cv2.fitEllipse(contours[index])
    props = {'Center_x': cx,'Center_y': cy,'Major Axis': MA,'Minor Axis': ma,'Rotated Angle': angle}
    ellipse_image = cv2.ellipse(imgray,ellipse,255))
    obj_properties[index] = props
    newFileWriter.writerow([cx,cy,(x,angle])

all_the_angle = [v['Rotated Angle'] for k,v in obj_properties.items()]
min_angle = 0
max_angle = 180
range_angle = max_angle - min_angle

# color mapping of Rotated Angle scalars to BGR values
cmap = plt.cm.get_cmap('jet')
for index,prop in obj_properties.items():
    v = (prop['Rotated Angle'] - min_angle) / range_angle
    r,g,b,a = [int(x) for x in cmap(v,bytes=True)]
    color_input = (b,r)
    colormap_image = cv2.drawContours(image,index,color_input,2)

plt.imshow(colormap_image,cmap=cmap)
cbar = plt.colorbar()
cbar.ax.set_yticklabels([])  # vertically oriented colorbar
cbar.set_label('Angle (Degree)')
plt.show()

# save the boundary,and colormap image
plt.imsave(boundary_output,boundary,cmap="gray")
cv2.imwrite(ellipse_output,ellipse_image)
colormap_image = plt.savefig(colormap_output)
# cv2.imwrite(colormap_output,colormap_image)
print("Saved contours,boundaries,ellipse and colormap as images and csv")

这些是我使用的图像。 patch_image patch_mask

我明白了。 patch_colormap

如何显示每个轮廓的旋转角度？例如，在每个边界内，我要添加其旋转角度的文本。

赞： edited_patch_colormap

解决方法

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matplotlibopencvopencv-pythonpythonpython-3.x