Forums - Problem with fcvFilterCanny3x3u8

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Problem with fcvFilterCanny3x3u8
Panayiotish
Join Date: 15 May 12
Posts: 10
Posted: Thu, 2012-09-13 03:45
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Hello all!

After managing combining FastCV with OpenCV the time to replace cvCanny with fcvFilterCanny3x3u8 came! Firstly I had to align the 8-bit source and destination images in order to pass them as arguments in fcvFilterCanny3x3u8. When I did that, the project was built without any errors, but when I run the project in my Android phone, I open ddms and I got the following after the execution of fcvFilterCanny3x3u8:

/home/User/android-ndk-r4-crystax/build/platforms/android-3/arch-arm/usr/include/fastcv/fastcv.inl@1846: (low >=0 ) && (low <= 255)

/home/User/android-ndk-r4-crystax/build/platforms/android-3/arch-arm/usr/include/fastcv/fastcv.inl@1847: (high >=0 ) && (high <= 255)

Is that an error? Because my project doesn't work as before from that point after. And if it is an error, what does it mean? 

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Re: Problem with fcvFilterCanny3x3u8
jeff4s Moderator
Join Date: 14 Mar 12
Posts: 54
Posted: Thu, 2012-09-13 10:03
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You are seeing assert error message. It appears that the parameters low & high are outside of valid range between 0 and 255.

Please set them within this range (also low < high) and try again.

Cheers,

-Jeff

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Re: Problem with fcvFilterCanny3x3u8
Panayiotish
Join Date: 15 May 12
Posts: 10
Posted: Sat, 2012-09-15 08:21
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I have found what the problem was finally. The thing was that with cvCanny I was using as hysterisis threshold the values of 1000 and 2000 (min and max respectively). Obviously, on fcvFilterCanny3x3u8 these values should be different. I used the default values (0 and 15) and everything was ok!

But the question now is what is the association of the values of the thresholds of cvCanny with the values of fcvFilterCanny3x3u8. In specific, what values should I put in fcvFilterCanny3x3u8 In order to achieve the same result as using cvCanny with values 1000 and 2000? 

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