Why is my call to putText creating a wavy image of lines?

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asked Sep 13 '12

ZachTM

458 ●7 ●12 ●19

updated Sep 14 '12

Andrey Pavlenko
1808 ●3 ●18 ●39

I have the following code trying to display the letter A on a window:

Mat letter = Mat(80,60,CV_8UC1);
putText(letter,"A",Point(0,0),CV_FONT_HERSHEY_PLAIN,8,Scalar(255,255,255));
namedWindow("Display",CV_WINDOW_NORMAL);
imshow("Display",letter);
imwrite("A.jpg",letter);
cvWaitKey(0);

That outputs this: image description

I do not understand what is going wrong can anyone tell me? I would really appreciate it!

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answered Sep 13 '12

AgentCain
261 ●1 ●5 ●10

updated Sep 13 '12

I would guess that these lines are just "memory garbage" since you dont load any kind of image on Mat letter. Also if im not mistaken, Point(0,0) is the upper left corner of the image (1st cell of a 2D matrix so its the upper-left-most cell) and it points to the lower left corner of your string "A" (so actually your letter "A" resides somewhere off the borders of the Mat)

Try Point (40,30) and then position it accordingly (since its more or less dead center)

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THanks you were right!

ZachTM (Sep 13 '12)edit

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Asked: Sep 13 '12

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Last updated: Sep 14 '12

Why is my call to putText creating a wavy image of lines? edit savecancel

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Why is my call to putText creating a wavy image of lines?