python手记(28)

 

#!/usr/bin/env python
#-*- coding: utf-8 -*-
import cv2
import numpy as np

fn="test2.jpg"

if __name__ == '__main__':
    print 'http://blog.csdn.net/myhaspl'
    print 'myhaspl@qq.com'
    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 cv2
import numpy as np

fn="test2.jpg"

if __name__ == '__main__':
    print 'http://blog.csdn.net/myhaspl'
    print 'myhaspl@qq.com'
    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()