图片亮度操作

import numpy as np

import cv2

peng = cv2.imread("images/4star.jpg")

cv2.imshow("peng",peng)

#创建一个增强矩阵

M = np.ones(peng.shape,dtype="uint8") * 75

added = cv2.add(peng, M) #相加生产新的图

cv2.imshow("Added",added)

subtracted = cv2.subtract(peng,M) #相减

cv2.imshow("subtracted",subtracted)

cv2.waitKey()

cv2.destroyAllWindows()

亮度操作效果

图片裁剪

import cv2

import numpy as np

imagePeng = cv2.imread("images/4star.jpg")

height, width = imagePeng.shape[:2]

#设置我们要裁剪的宽高

start_row,start_col = int(height * 0.45),int(width * 0.45) #起点

end_row,end_col = int(height * 0.75), int(width * 0.75) # 终点

#用前面的起点跟终点来裁剪我们的图片

croppedPeng = imagePeng[start_row:end_row, start_col:end_col]

# cv2.imshow("Original Image",imagePeng)

# cv2.waitKey(0)

cv2.imshow("Crop Image",croppedPeng)

cv2.waitKey(0)

cv2.destroyAllWindows()

裁剪之后的图片

图片旋转，图片旋转有两种方式:

方式1：

import cv2

import numpy as np

image = cv2.imread("images/4star.jpg")

height, width = image.shape[:2]

# 旋转矩阵

rotation_matrix = cv2.getRotationMatrix2D((width/2,height/2),40,1)

# 旋转之后的画面

rotation_image = cv2.warpAffine(image,rotation_matrix,(width,height))

cv2.imshow("Rotation",rotation_image)

cv2.waitKey()

cv2.destroyAllWindows()

旋转40度，图片尺寸没变

方式二，这种方式图片尺寸不变，单图片的尺寸会裁剪，这中方式只能每次旋转90度

import cv2

import numpy as np

image = cv2.imread('images/4star.jpg')

rotated_image = cv2.transpose(image)

cv2.imshow("rotated_image",rotated_image)

cv2.waitKey()

cv2.destroyAllWindows()

图像金字塔，放到缩小

import cv2

import numpy as np

image = cv2.imread("images/4star.jpg")

# 把图片縮小 3/4.

image_scaled = cv2.resize(image,None,fx=0.75, fy=0.75)

cv2.imshow("scaling - Linear", image_scaled)

cv2.waitKey()

# 把图片放大兩倍

image_scaled2 = cv2.resize(image,None,fx=2, fy=2)

cv2.imshow("scaling - no - Cubic", image_scaled2)

cv2.waitKey()

# 把图片放大道指定的大小

image_scaled3 = cv2.resize(image,(900,400),interpolation = cv2.INTER_AREA)

cv2.imshow("scaling - AREA", image_scaled3)

cv2.waitKey()

图片金字塔

使用提供的方法

import cv2

image = cv2.imread("images/4star.jpg")

smller = cv2.pyrDown(image)

larger = cv2.pyrUp(image)

cv2.imshow("Original",image)

cv2.imshow("Smaller",smller)

cv2.imshow("larger",larger)

cv2.waitKey()

cv2.destroyAllWindows()

图片平移，实现代码在下面

import cv2

import numpy as np

image = cv2.imread('images/4star.jpg')

# 取出寬高

height, width = image.shape[:2]

# 設置平移之後的寬高

quarter_height, quarter_width = height/4 , width/4

#      / 1,0,tx/

# T = / 0,1,ty/

# T 平移時候的矩陣

T = np.float32([[1,0,quarter_width],[0,1,quarter_height]])

image_translation = cv2.warpAffine(image, T, (width,height))

cv2.imshow("Translation",image_translation)

cv2.waitKey()

cv2.destroyAllWindows()

OpenCV 画图

画正方形 色值是0  黑心

import cv2

import numpy as np

# 创建一个正方形的图像

image = np.zeros((512,1612,3),np.uint8)

# 创建一个黑白的正方形

image_bw = np.zeros((512,1612),np.uint8)

cv2.imshow("Black Rectangle (color)",image)

cv2.imshow("Black Rectangle (B&W)",image_bw)

cv2.waitKey(0)

cv2.destroyAllWindows()

在这个图像上再画线，再上点颜色

#在上面代码上画先

image = np.zeros((512,512,3),np.uint8)

cv2.line(image,(0,0),(511,511),(255,127,0),5)#参数，起点、终点，颜色、粗细

cv2.imshow("Line",image)

cv2.waitKey(0)

cv2.destroyAllWindows()

在这个图像上再画线

在图像上画矩形，注意线条的大小为-1时，为实心矩形

import cv2

import numpy as np

image = np.zeros((512,512,3),np.uint8)

cv2.rectangle(image,(100,100),(300,250),(127,50,127),5)

# cv2.rectangle(image,(100,100),(300,250),(127,50,127),-1) 实心矩形

cv2.imshow("Rectangle",image)

cv2.waitKey(0)

cv2.destroyAllWindows()

矩形绘图

画圆，-1也是实心圆

import cv2

import numpy as np

image = np.zeros((512,512,3),np.uint8)

cv2.circle(image,(350,350),100,(15,75,50),-1)

cv2.imshow("circle",image)

cv2.waitKey(0)

cv2.destroyAllWindows()

多边形

import cv2

import numpy as np

image = np.zeros((512,512,3),np.uint8)

#给出多边形每个顶点的座标

pts = np.array([[10,50],[400,50],[90,200],[50,500]],np.int32)

pts = pts.reshape((-1,1,2)) # 形狀出來了

cv2.polylines(image,[pts],True,(0,0,255),5)

cv2.imshow("Polygon",image)

cv2.waitKey(0)

cv2.destroyAllWindows()

加文字

import cv2

import numpy as np

image = np.zeros((512,512,3),np.uint8)

cv2.putText(image,"Hello peng",(75,200),cv2.FONT_HERSHEY_COMPLEX,2,(100,170,0),3)

## cv2.putText(在什么上面写字,"文字的内容",(文字的起始座标),字体,字体大小,(颜色),粗细)

cv2.imshow("Text",image)

cv2.waitKey(0)

cv2.destroyAllWindows()

opencv 画文字