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Comparison betweens resize/interpolation algorithms

asked 2017-05-12 14:07:23 -0500

Jamesac gravatar image

updated 2020-10-11 14:16:59 -0500

Hello, I'm trying to evaluate nearest, bilinear and bicubic interpolation algorithms from the resize function but all my images are exactly the same.

Can anyone help me?

Mat img; 
Mat img2;

img = imread("face2.png", IMREAD_UNCHANGED);

Size size(720,1080);

vector<int> com_param;
com_param.push_back(CV_IMWRITE_JPEG_QUALITY);
com_param.push_back(9);
cv::resize(img, img2, size, cv::INTER_NEAREST);
imwrite("nearest.jpg",img2,com_param);
cv::resize(img, img2, size, cv::INTER_NEAREST);
imwrite("bilinear.jpg",img2,com_param);
cv::resize(img, img2, size, cv::INTER_NEAREST);
imwrite("cubic.jpg",img2,com_param);
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answered 2017-05-12 14:14:55 -0500

LBerger gravatar image

Use flags! and don't save in a compress format

cv::resize(img, img2, size, cv::INTER_NEAREST);
imwrite("nearest.png",img2);
cv::resize(img, img2, size, cv::INTER_LINEAR );
imwrite("bilinear.png",img2);
cv::resize(img, img2, size, INTER_CUBIC );
imwrite("cubic.png",img2);
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Comments

Thank you for the answer.

Done it already but no changes. Which flags do you mean?

Jamesac gravatar imageJamesac ( 2017-05-22 12:58:53 -0500 )edit

to see a difference orignal size must be smaller tahn destination size

LBerger gravatar imageLBerger ( 2017-05-22 14:12:08 -0500 )edit
1

Thank you for your help. I figure out that I wasn't using factor size as a parameter.

It is working now.

Jamesac gravatar imageJamesac ( 2017-06-12 11:23:11 -0500 )edit

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Asked: 2017-05-12 14:07:23 -0500

Seen: 1,087 times

Last updated: May 12 '17