opencv-图片处理及绘图

原始图片：

彩色图片灰度化

方式1：

import cv2  # 导入cv库
img = cv2.imread('image2.jpg',0)
cv2.imwrite('gray_image.jpg',img)

方式2：

import cv2
img = cv2.imread('image2.jpg',1)
dst = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)# 颜色空间转换 1 data 2 BGR gray
cv2.imshow('dst',dst)

方式3

#方法4 gray = r*0.299+g*0.587+b*0.114
import cv2
import numpy as np
img = cv2.imread('image0.jpg',1)
imgInfo = img.shape
height = imgInfo[0]
width = imgInfo[1]
dst = np.zeros((height,width,3),np.uint8)
for i in range(0,height):
    for j in range(0,width):
        (b,g,r) = img[i,j]
        b = int(b)
        g = int(g)
        r = int(r)
        gray = r*0.299+g*0.587+b*0.114
        dst[i,j] = np.uint8(gray)
cv2.imshow('dst',dst)

马赛克

import cv2 # 导入cv库
import numpy as np
img = cv2.imread('image2.jpg',1) # 读取图片文件， 1：彩色， 0：灰色
#cv2.imshow('src',img)
imgInfo = img.shape  # 获取图片的维度
height = imgInfo[0]
width = imgInfo[1]
for m in range(200,400):
    for n in range(400,500):
        # pixel ->10*10
        if m%10 == 0 and n%10==0:
            for i in range(0,10):
                for j in range(0,10):
                    (b,g,r) = img[m,n]
                    img[i+m,j+n] = (b,g,r)
cv2.imwrite('msk.jpg',img)

边缘检测

方式1：

import cv2
import numpy as np
import random
img = cv2.imread('image2.jpg',1)
imgInfo = img.shape
height = imgInfo[0]
width = imgInfo[1]
#cv2.imshow('src',img)

#canny 1 gray 2 高斯 3 canny
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
imgG = cv2.GaussianBlur(gray,(3,3),0)
dst = cv2.Canny(img,50,50) #图片卷积——》th
#cv2.imshow('dst',dst)
cv2.imwrite('canny.jpg',dst)

方式2：

import cv2
import numpy as np
import random
import math

img = cv2.imread('image2.jpg', 1)
imgInfo = img.shape
height = imgInfo[0]
width = imgInfo[1]
#cv2.imshow('src', img)

# sobel 1 算子模版 2 图片卷积 3 阈值判决
# [1 2 1          [ 1 0 -1
#  0 0 0            2 0 -2
# -1 -2 -1 ]       1 0 -1 ]

# [1 2 3 4] [a b c d] a*1+b*2+c*3+d*4 = dst
# sqrt(a*a+b*b) = f>th
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
dst = np.zeros((height, width, 1), np.uint8)
for i in range(0, height - 2):
    for j in range(0, width - 2):
        gy = gray[i, j] * 1 + gray[i, j + 1] * 2 + gray[i, j + 2] * 1 - gray[i + 2, j] * 1 - gray[i + 2, j + 1] * 2 - \
             gray[i + 2, j + 2] * 1
        gx = gray[i, j] + gray[i + 1, j] * 2 + gray[i + 2, j] - gray[i, j + 2] - gray[i + 1, j + 2] * 2 - gray[
            i + 2, j + 2]
        grad = math.sqrt(gx * gx + gy * gy)
        if grad > 50:
            dst[i, j] = 255
        else:
            dst[i, j] = 0
cv2.imwrite('sobel.jpg',dst)

颜色风格变化

import cv2
import numpy as np
img = cv2.imread('image2.jpg',1)
#cv2.imshow('src',img)
imgInfo = img.shape
height = imgInfo[0]
width = imgInfo[1]
#rgb -》RGB new “蓝色”
# b=b*1.5
# g = g*1.3
dst = np.zeros((height,width,3),np.uint8)
for i in range(0,height):
    for j in range(0,width):
        (b,g,r) = img[i,j]
        b = b*1.5
        g = g*1.3
        if b>255:
            b = 255
        if g>255:
            g = 255
        dst[i,j]=(b,g,r)
#cv2.imshow('dst',dst)
cv2.imwrite('dst2.jpg',dst)

油画特效

import cv2
import numpy as np
img = cv2.imread('image2.jpg',1)
#cv2.imshow('src',img)
imgInfo = img.shape
height = imgInfo[0]
width = imgInfo[1]
gray = cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)
dst = np.zeros((height,width,3),np.uint8)
for i in range(4,height-4):
    for j in range(4,width-4):
        array1 = np.zeros(8,np.uint8)
        for m in range(-4,4):
            for n in range(-4,4):
                p1 = int(gray[i+m,j+n]/32)
                array1[p1] = array1[p1]+1
        currentMax = array1[0]
        l = 0
        for k in range(0,8):
            if currentMax<array1[k]:
                currentMax = array1[k]
                l = k
        # 简化 均值
        for m in range(-4,4):
            for n in range(-4,4):
                if gray[i+m,j+n]>=(l*32) and gray[i+m,j+n]<=((l+1)*32):
                    (b,g,r) = img[i+m,j+n]
        dst[i,j] = (b,g,r)
cv2.imwrite('dst3.jpg',dst)

线段绘制

import cv2
import numpy as np
newImageInfo = (500,500,3)
dst = np.zeros(newImageInfo,np.uint8)
# line
# 绘制线段 1 dst 2 begin 3 end 4 color
cv2.line(dst,(100,100),(400,400),(0,0,255))
# 5 line w
cv2.line(dst,(100,200),(400,200),(0,255,255),20)
# 6 line type
cv2.line(dst,(100,300),(400,300),(0,255,0),20,cv2.LINE_AA)

cv2.imwrite('line.jpg',dst)

绘制矩形、圆形

import cv2
import numpy as np
newImageInfo = (500,500,3)
dst = np.zeros(newImageInfo,np.uint8)
#  1 2 左上角 3 右下角 4 5 fill -1 >0 line w
cv2.rectangle(dst,(50,100),(200,300),(255,0,0),5)
# 2 center 3 r
cv2.circle(dst,(300,100),(50),(0,255,0),2)
# 2 center 3 轴(a,b) 4 angle 5 begin 6 end 7
cv2.ellipse(dst,(256,350),(150,100),30,0,360,(255,255,0),-1)

points = np.array([[350,50],[140,140],[200,170],[250,250],[350,50]],np.int32)
print(points.shape)
points = points.reshape((-1,1,2))
print(points.shape)
cv2.polylines(dst,[points],True,(0,0,255))
cv2.imwrite('dst4.jpg',dst)

添加文字

import cv2
import numpy as np
img = cv2.imread('image2.jpg',1)
font = cv2.FONT_HERSHEY_SIMPLEX
cv2.rectangle(img,(400,300),(950,900),(0,255,0),3)
# 1 dst 2 文字内容 3 坐标 4 5 字体大小 6 color 7 粗细 8 line type
cv2.putText(img,'this is flower',(500,500),font,2,(200,100,255),3,cv2.LINE_AA)
cv2.imwrite('word.jpg',img)