Simple stuff! bit selection and counters! HELP!

[Altera_Forum]

Hi guys, 

 I am a bit of a newbie to programming in general and am doing a project for school. I am using Quartus and I have a DE2 board and a terasic camera which I am using to capture a video stream and do image processing on it (simple colour segmentation).   Now I need to feed these filtered pixels into Nios for further manipulations so I have to reduce the resolution of the image otherwise Nios has memory issues.   What I need to do is only sample every 20th pixel. I have the x and y coordinates of the pixels. So I thought I would do this in schematic capture and have a modulus counter counting up til 20 for x and y, and only taking that pixel... how would I do this? any clue?  My resolution is 640x480 so my aim is to reduce this to 32x24 because that would be a much smaller array to feed into Nios.   Any help would be highly appreciated because this is very urgent.  Thankssss Dani

[Altera_Forum]

--- Quote Start ---  Hi guys,   Now I need to feed these filtered pixels into Nios for further manipulations so I have to reduce the resolution of the image otherwise Nios has memory issues.    What I need to do is only sample every 20th pixel. I have the x and y coordinates of the pixels. So I thought I would do this in schematic capture and have a modulus counter counting up til 20 for x and y, and only taking that pixel... how would I do this? any clue?   My resolution is 640x480 so my aim is to reduce this to 32x24 because that would be a much smaller array to feed into Nios.    --- Quote End ---     Before actually feeding this data to the cpu, you can simply store it on an on-board memory. Later, you can sample the data from the memory either directly in NIOS or in your HDL design (from where you can feed it to NIOS).

[Altera_Forum]

[slightly off topic] The standard approach in reducing the image size - without losing information - is to low-pass filter the image first, and then downsample. You could be doing that, you just didn't mention it.