standard algorithm

Hai,

I am new to DSP.I have to do upscaling and downscaling of a image and
implemented in FPGA.I referred resources and understood the bilinear
method with FIR filter used for this..

I knew about the basic FIR filter.I want to know the following:

1.Any standard method or algorithms which can do upscaling and
downscaling the image..Pls suggest the link and the method and its
equation..

2.And also suggest do i need to use cascaded version of FIR filter or
2D FIR filter or polyphase FIR filter...Which one is most recommended
as per the standard method.

3.Can i use a 2D -FIR filter for both upscaling and downscaling a
image without zero padding?

Pls share u r views with to proceed further..

regards,
raj

On Oct 15, 5:07&#4294967295;am, raj <rajesh.o...@gmail.com> wrote:
> Hai,
>
> I am new to DSP.I have to do upscaling and downscaling of a image and
> implemented in FPGA.I referred resources and understood the bilinear
> method with FIR filter used for this..
>
> I knew about the basic FIR filter.I want to know the following:
>
> 1.Any standard method or algorithms which can do upscaling and
> downscaling the image..Pls suggest the link and the method and its
> equation..
>
> 2.And also suggest do i need to use cascaded version of FIR filter or
> 2D FIR filter or polyphase FIR filter...Which one is most recommended
> as per the standard method.
>
> 3.Can i use a 2D -FIR filter for both upscaling and downscaling a
> image without zero padding?
>
> Pls share u r views with to proceed further..
>
> regards,
> raj

The solution to your problem is to study or hire someone who did.

Dirk

On Oct 15, 5:07&#4294967295;am, raj <rajesh.o...@gmail.com> wrote:
> Hai,
>
> I am new to DSP.I have to do upscaling and downscaling of a image and
> implemented in FPGA.I referred resources and understood the bilinear
> method with FIR filter used for this..
>
> I knew about the basic FIR filter.I want to know the following:
>
> 1.Any standard method or algorithms which can do upscaling and
> downscaling the image..Pls suggest the link and the method and its
> equation..
>
> 2.And also suggest do i need to use cascaded version of FIR filter or
> 2D FIR filter or polyphase FIR filter...Which one is most recommended
> as per the standard method.
>
> 3.Can i use a 2D -FIR filter for both upscaling and downscaling a
> image without zero padding?
>
> Pls share u r views with to proceed further..
>
> regards,
> raj

There are a myriad ways to resample an image. Common approaches use
bilinear or bicubic interpolation. An old but coarse way is to use the
nearest neighbor. You can even use a sin(x)/x interpolation. There are
a host of computer graphics books that cover these common algorithms.
Try a visit to your university library and look up image processing.

Clay

> 1.Any standard method or algorithms which can do upscaling and
> downscaling the image..Pls suggest the link and the method and its
> equation..

It should be somewhat like the conventional signal processing for 1-D
signal, upsampling then filtering off some images; anti-alias
filtering then downsampling. And 2D filters should be used in
filtering process.

> 2.And also suggest do i need to use cascaded version of FIR filter or
> 2D FIR filter or polyphase FIR filter...Which one is most recommended
> as per the standard method.
>
> 3.Can i use a 2D -FIR filter for both upscaling and downscaling a
> image without zero padding?

> Pls share u r views with to proceed further..
>
> regards,
> raj