Python image compression algorithm example analysis based on opencv

This article mainly introduces Python's image compression algorithm based on opencv, and analyzes the common operating techniques and precautions for using opencv for image compression in the form of examples. Friends in need can refer to the following

The examples of this article are explained Python's image compression algorithm based on opencv. Share it with everyone for your reference, the details are as follows:

Interpolation method:

CV_INTER_NN - nearest neighbor interpolation,
CV_INTER_LINEAR - bilinear interpolation (used by default )
CV_INTER_AREA - Use pixel-relative resampling. This method can avoid ripples when the image is zoomed out. When the image is enlarged, it is similar to the CV_INTER_NN method..
CV_INTER_CUBIC - cubic interpolation.

Function cvResize changes the size of the image src to the same size as dst. If ROI is set, the function will support ROI as usual.

Procedure 1: Image Compression (First Edition)

# coding=utf-8
import time
time1 = time.time()
import cv2
image=cv2.imread("c:/1.jpg")
res = cv2.resize(image, (1280,960), interpolation=cv2.INTER_AREA)
# cv2.imshow('image', image)
# cv2.imshow('resize', res)
# cv2.waitKey(0)
# cv2.destroyAllWindows()
cv2.imwrite("C:/5.jpg",res)
time2=time.time()
print u'总共耗时：' + str(time2 - time1) + 's'

4.19M—377k compressed 11 times

Procedure 2: Image Compression (Second Edition)

#-*-coding:utf-8-*-
#############设置编码################
import sys
reload(sys)
sys.setdefaultencoding('utf-8')
###################导入计算机视觉库opencv和图像处理库PIL####################
from PIL import Image
from PIL import ImageEnhance
from PIL import ImageFilter
import cv2
import time
time1 = time.time()
####################读入图像###############################
image=cv2.imread("c:/pic//0.jpg")
####################双三次插值#############################
res = cv2.resize(image, (1280,960), interpolation=cv2.INTER_AREA)
####################写入图像########################
cv2.imwrite("C:/pic/101.jpg",res)
###########################图像对比度增强##################
imgE = Image.open("c:/pic/101.jpg")
imgEH = ImageEnhance.Contrast(imgE)
img1=imgEH.enhance(2.8)
########################图像转换为灰度图###############
gray = img1.convert("L")
gray.save("C:/pic/3.jpg")
##########################图像增强###########################
# 创建滤波器，使用不同的卷积核
gary2=gray.filter(ImageFilter.DETAIL)
gary2.save("C:/pic/2.jpg")
#############################图像点运算#################
gary3=gary2.point(lambda i:i*0.9)
gary3.save("C:/pic/4.jpg")
# img1.show("new_picture")
time2=time.time()
print u'总共耗时：' + str(time2 - time1) + 's'

4.17M–>290kb

Program 3: Function version

#-*-coding:utf-8-*-
#############设置编码################
import sys
reload(sys)
sys.setdefaultencoding('utf-8')
############导入计算机视觉库opencv和图像处理库PIL####################
from PIL import Image
from PIL import ImageEnhance
from PIL import ImageFilter
import cv2
import time
time1 = time.time()
########################自定义图像压缩函数############################
def img_zip(path,filename1,filename2):
  image = cv2.imread(path+filename1)
  res = cv2.resize(image, (1280, 960), interpolation=cv2.INTER_AREA)
  cv2.imwrite(path+filename2, res)
  imgE = Image.open(path+filename2)
  imgEH = ImageEnhance.Contrast(imgE)
  img1 = imgEH.enhance(2.8)
  gray1 = img1.convert("L")
  gary2 = gray1.filter(ImageFilter.DETAIL)
  gary3 = gary2.point(lambda i: i * 0.9)
  gary3.save(path+filename2)
################################主函数##################################
if __name__ == '__main__':
  path=u"c:/pic/"
  filename1="0.jpg"
  filename2="1.jpg"
  img_zip(path,filename1,filename2)
  time2 = time.time()
  print u'总共耗时：' + str(time2 - time1) + 's'

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