topic Image Geometry Transform - rotation direction in Intel® Integrated Performance Primitives

Image Geometry Transform - rotation direction

Mike4 — Thu, 25 Nov 2010 12:17:53 GMT

Hi all !

I have a problem using the ippiRotate_xxx methods.

with 8u_C1R and 8u_C3R the direction is clockwise

with 8u_C4R the direction is counterclockwise

I use the IPP 7.01 library.

Is it a normal behavior ?

Thanks

Mike

Image Geometry Transform - rotation direction

Yuri_Tikhomirov__Int — Thu, 25 Nov 2010 12:55:16 GMT

HelloMike,

Could you please provide a sample code with more information about your problem?
What is interpolation method? Whatis image size? Angle?

Thanks,
Beg

Image Geometry Transform - rotation direction

Chao_Y_Intel — Fri, 26 Nov 2010 07:12:38 GMT

Hi Beg,

You can also run the IPP ippiDemo.exe at Intel\IPP\6.1.6.056\ia32\demo\, and see if this is a code error, or a bug related with IPP.

Regards,
Chao

Image Geometry Transform - rotation direction

Yuri_Tikhomirov__Int — Fri, 26 Nov 2010 08:12:16 GMT

Please take a look at thepictures obtained by using ippiDemo application.
Rotation of (30) and (360-30) degrees.

What is wrong ?

Thanks,
Beg

Image Geometry Transform - rotation direction

Mike4 — Mon, 29 Nov 2010 15:13:20 GMT

Hi all,

may be I made a mistake but I used the same code with ipp 3.0 and I have never had any error.

here is my code :

double dAngle = 45;

double dBounds[2][2];

IppiRect rect = {0, 0, 640, 480};

IppStatus status = ippiGetRotateBound(rect, dBounds, dAngle, 0, 0);

IppiRect rectOutput = {0, 0,dBounds[1][0] - dBounds[0][0],dBounds[1][1] - dBounds[0][1]};

IppiSize sizeInput = {rect.width, rect.height};

status = ippiRotate_8u_C3R(pInputBuffer, sizeInput, iStrideIn, rect,

pOutputBuffer, iStrideOut, rectOutput,

dAngle, -dBounds[0][0], -dBounds[0][1], IPPI_INTER_LINEAR);

status = ippiRotate_8u_C4R(

pInputBuffer, sizeInput, iStrideIn, rect,

pOutputBuffer, iStrideOut, rectOutput,

dAngle,-dBounds[0][0], -dBounds[0][1], IPPI_INTER_LINEAR);

(the pInputBuffer for the 2 above versions are respectively in 24bits and 32bits)

8u_C3R and 8u_C1R rotate in clockwise direction and 8u_C4R in counterclockwise direction

I have the same behavior between 8u_C4R and 8u_AC4R.

Later, if necessary, I will put a test program with full c++ source code. For the moment I haven't the time to do it. To patch the problem I invert the angle in 8 and 24 bits.

I made the tests with ippiDemo, I have the same rotation direction with 24 et 32bits pictures but in clockwise direction (the inverse as noticed in documentation).

Thanks