python手记(28)

#!/usr/bin/env python#-*- coding: utf-8 -*-import cv2import numpy as npfn="test2.jpg"if __name__ == '__main__':    print 'http://blog.csdn.net/myhaspl'    print '[e-mail]'    print    print 'loading %s ...' % fn    img = cv2.imread(fn)    sp=img.shape    print sp    #height    sz1=sp[0]    #width    sz2=sp[1]    print 'width:%d\nheight:%d'%(sz2,sz1)    #创建一个窗口并显示图像    cv2.namedWindow('img')         cv2.imshow('img', img)    #复制图像    myimg2= img.copy();    cv2.namedWindow('myimg2')         cv2.imshow('myimg2', myimg2)        #复制并转换为黑白图像    myimg1=cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)    cv2.namedWindow('myimg1')         cv2.imshow('myimg1', myimg1)     cv2.waitKey()    cv2.destroyAllWindows()

关于图像保存问题

Python: cv2.imwrite(filename, img[, params]) → retval

C: int cvSaveImage(const char* filename, const CvArr* image, const int* params=0)

Parameters:

• filename – Name of the file.
• image – Image to be saved.
• params –

  Format-specific save parameters encoded as pairs paramId_1,paramValue_1, paramId_2, paramValue_2, ... . The following parameters are currently supported:

  • For JPEG, it can be a quality ( CV_IMWRITE_JPEG_QUALITY ) from 0 to 100 (the higher is the better). Default value is 95.
  • For WEBP, it can be a quality ( CV_IMWRITE_WEBP_QUALITY ) from 1 to 100 (the higher is the better). By default (without any parameter) and for quality above 100 the lossless compression is used.
  • For PNG, it can be the compression level (CV_IMWRITE_PNG_COMPRESSION ) from 0 to 9. A higher value means a smaller size and longer compression time. Default value is 3.
  • For PPM, PGM, or PBM, it can be a binary format flag (CV_IMWRITE_PXM_BINARY ), 0 or 1. Default value is 1.

#!/usr/bin/env python#-*- coding: utf-8 -*-import cv2import numpy as npfn="test2.jpg"if __name__ == '__main__':    print 'http://blog.csdn.net/myhaspl'    print '[e-mail]'    print    print 'loading %s ...' % fn    img = cv2.imread(fn)     #复制并转换为黑白图像    myimg1=cv2.cvtColor(img,cv2.COLOR_BGR2GRAY)    #保存图像    myimg2=cv2.imwrite("test3.png", myimg1,[int(cv2.IMWRITE_PNG_COMPRESSION), 7])    img = cv2.imread("test3.png")         cv2.namedWindow('img')         cv2.imshow('img', img)     cv2.waitKey()    cv2.destroyAllWindows()