OpenCV入门6——图像基本变换
文章目录
- 图像的放大与缩小
-
- 缩放算法
- 放大
- 图像的翻转
- 图像的旋转
- 仿射变换之图像平移
- 仿射变换之获取变换矩阵
- 仿射变换之变换矩阵之二
- OpenCV透视变换
图像的放大与缩小
缩放算法
# -*- coding: utf-8 -*-
import cv2
import numpy as np
img = cv2.imread('E://pic//4.jpg')
# (600, 480, 3)
new_img = cv2.resize(img, (300, 240))
new_img2 = cv2.resize(img, (300, 240), interpolation=cv2.INTER_AREA)
cv2.imshow('new_img', new_img)
cv2.imshow('img', img)
cv2.imshow('new_img2', new_img2)
key = cv2.waitKey(0) & 0xff
if key == ord('q'):
cv2.destroyAllWindows()
# -*- coding: utf-8 -*-
import cv2
import numpy as np
img = cv2.imread('E://pic//4.jpg')
# (600, 480, 3)
new_img = cv2.resize(img, None, fx=0.3, fy=0.3)
new_img2 = cv2.resize(img, (300, 240), interpolation=cv2.INTER_AREA)
cv2.imshow('new_img', new_img)
cv2.imshow('img', img)
cv2.imshow('new_img2', new_img2)
key = cv2.waitKey(0) & 0xff
if key == ord('q'):
cv2.destroyAllWindows()
放大
# -*- coding: utf-8 -*-
import cv2
import numpy as np
img = cv2.imread('E://pic//4.jpg')
# (600, 480, 3)
new_img = cv2.resize(img, None, fx=1.3, fy=1.3)
new_img2 = cv2.resize(img, (300, 240), interpolation=cv2.INTER_AREA)
cv2.imshow('new_img', new_img)
cv2.imshow('img', img)
cv2.imshow('new_img2', new_img2)
key = cv2.waitKey(0) & 0xff
if key == ord('q'):
cv2.destroyAllWindows()
图像的翻转
# -*- coding: utf-8 -*-
import cv2
import numpy as np
img = cv2.imread('E://pic//4.jpg')
# 上下翻转
img2 = cv2.flip(img, 0)
# 左右翻转
img3 = cv2.flip(img, 1)
# 上下左右翻转
img4 = cv2.flip(img, -1)
cv2.imshow('img', img)
cv2.imshow('img2', img2)
cv2.imshow('img3', img3)
cv2.imshow('img4', img4)
key = cv2.waitKey(0) & 0xff
if key == ord('q'):
cv2.destroyAllWindows()
图像的旋转
# -*- coding: utf-8 -*-
import cv2
import numpy as np
img = cv2.imread('E://pic//4.jpg')
img2 = cv2.rotate(img, cv2.ROTATE_90_COUNTERCLOCKWISE)
img3 = cv2.rotate(img, cv2.ROTATE_180)
img4 = cv2.rotate(img, cv2.ROTATE_90_CLOCKWISE)
cv2.imshow('img', img)
cv2.imshow('img2', img2)
cv2.imshow('img3', img3)
cv2.imshow('img4', img4)
key = cv2.waitKey(0) & 0xff
if key == ord('q'):
cv2.destroyAllWindows()
仿射变换之图像平移
详细见官方文档
第一行的第三列是x轴偏移量，第二行第三列是y轴偏移量
# -*- coding: utf-8 -*-
import cv2
import numpy as np
img = cv2.imread('E://pic//4.jpg')
w, h, ch = img.shape
M = np.float32([[1, 0, 100], [0, 1, 20]])
img2 = cv2.warpAffine(img, M, (h, w))
cv2.imshow('img', img)
cv2.imshow('img2', img2)
key = cv2.waitKey(0) & 0xff
if key == ord('q'):
cv2.destroyAllWindows()
仿射变换之获取变换矩阵
# -*- coding: utf-8 -*-
import cv2
import numpy as np
img = cv2.imread('E://pic//10.jpg')
w, h, ch = img.shape
# M = np.float32([[1, 0, 100], [0, 1, 20]])
# 旋转的角度为逆时针
M = cv2.getRotationMatrix2D((100, 100), 30, 1)
M2 = cv2.getRotationMatrix2D((h / 2, w / 2), 60, 0.6)
# 如果想改变新图像尺寸，需修改dsize
img2 = cv2.warpAffine(img, M, (h, w))
img3 = cv2.warpAffine(img, M2, (h, w))
cv2.imshow('img', img)
cv2.imshow('img2', img2)
cv2.imshow('img3', img3)
key = cv2.waitKey(0) & 0xff
if key == ord('q'):
cv2.destroyAllWindows()
仿射变换之变换矩阵之二
# -*- coding: utf-8 -*-
import cv2
import numpy as np
img = cv2.imread('E://pic//10.jpg')
w, h, ch = img.shape
# M = np.float32([[1, 0, 100], [0, 1, 20]])
# 旋转的角度为逆时针
# M = cv2.getRotationMatrix2D((100, 100), 30, 1)
# M2 = cv2.getRotationMatrix2D((h / 2, w / 2), 60, 0.6)
src = np.float32([[100, 200], [300, 200], [100, 400]])
dst = np.float32([[50, 100], [200, 400], [90, 300]])
M = cv2.getAffineTransform(src, dst)
# 如果想改变新图像尺寸，需修改dsize
img2 = cv2.warpAffine(img, M, (h, w))
# img3 = cv2.warpAffine(img, M2, (h, w))
cv2.imshow('img', img)
cv2.imshow('img2', img2)
# cv2.imshow('img3', img3)
key = cv2.waitKey(0) & 0xff
if key == ord('q'):
cv2.destroyAllWindows()
# -*- coding: utf-8 -*-
import cv2
import numpy as np
img = cv2.imread('E://pic//10.jpg')
w, h, ch = img.shape
# M = np.float32([[1, 0, 100], [0, 1, 20]])
# 旋转的角度为逆时针
# M = cv2.getRotationMatrix2D((100, 100), 30, 1)
# M2 = cv2.getRotationMatrix2D((h / 2, w / 2), 60, 0.6)
src = np.float32([[100, 200], [300, 200], [100, 400]])
dst = np.float32([[50, 100], [200, 400], [60, 500]])
M = cv2.getAffineTransform(src, dst)
# 如果想改变新图像尺寸，需修改dsize
img2 = cv2.warpAffine(img, M, (h, w))
# img3 = cv2.warpAffine(img, M2, (h, w))
cv2.imshow('img', img)
cv2.imshow('img2', img2)
# cv2.imshow('img3', img3)
key = cv2.waitKey(0) & 0xff
if key == ord('q'):
cv2.destroyAllWindows()
OpenCV透视变换
# -*- coding: utf-8 -*-
import cv2
import numpy as np
cv2.namedWindow('img', cv2.WINDOW_NORMAL)
cv2.namedWindow('img2', cv2.WINDOW_NORMAL)
img = cv2.imread('perspective.jpeg')
src = np.float32([[100, 1000], [2100, 1000], [0, 4000], [2500, 3900]])
dst = np.float32([[0, 0], [2300, 0], [0, 3000], [2300, 3000]])
M = cv2.getPerspectiveTransform(src, dst)
img2 = cv2.warpPerspective(img, M, (2300, 3000))
cv2.imshow('img', img)
cv2.imshow('img2', img2)
key = cv2.waitKey(0) & 0xff
if key == ord('q'):
cv2.destroyAllWindows()
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