How to use rfft2d_fr16 or rfft2d_fr32 on grayscale images

Hi Santhosh,

Thank you for your inquiry.

You can get the detailed information about this library function and sample code from the below CCES help path

CrossCore® Embedded Studio 2.12.0 > Blackfin® Development Tools Documentation > C/C++ Compiler and Library Manual for Blackfin® Processors > DSP Run-Time Library > DSP Run-Time Library Reference

Hope this helps.

Best Regards,
Santhakumari.V

Hi Santhakumari,

I worked on rfft2d_fr16() , to validate this I used it's FFT output as input to ifft2d_fr16(), for FFT size 64 , twiddle stride 1, block exponent 12, scale 1 , but I am getting 12 bits scaled while compared input see below

1) My input is img[64*64 ]={0x7fff,0x7fff,0x7fff,0x7fff,0x7fff,.......0x7fff}

ifft2d_fr16 output is ={0x7,0x7,0x7,0x7,.......0x7};

2) My input is img[64*64 ]={0x4000,0x4000,0x4000,0x4000,........0x4000}

Ifft2d_fr16 output is ={0x4,0x4,0x4,0x4,.......0x4};

I changed my scaling values in both functions many times as well block exponent values also, but there is no change in ifft out.

If changed FFT_SIZE to 32 or 16 then output occuring like 8, 6 bit scaling respectively, my question is while I am taking 64*64 input image, should i use only 64 FFT size or other FFT size.

Another question is can i change my scaling factor .

Thanks and regards,

Santhosh