Hi,

interesting project, how are you doing it? Back-projection and a IR-cam? I am not an image processing whiz, but you could try to subtract your image from a lowpass-filtered copy of the same image. Should give a highpass then. But i am sure there are more clever ways of doing it. Basically a HP can be done using a delay and a subtraction.

regards, PP

• punchik punchik punchikk@yahoo.com [2007-11-05 22:50]:

hi i making a multituouch surface with pd, i want be able to filter the low and middle bands in the video from my web cam. im interesting in just letting the high images pass... is there something like a high pass filter for imagens?

thanks

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punchik punchik wrote:

hi i making a multituouch surface with pd, i want be able to filter the low and middle bands in the video from my web cam. im interesting in just letting the high images pass... is there something like a high pass filter for imagens?

in Gem: [pix_convolve] does spatial convolution with a square kernel. fill it with the right coefficients to produce a spatial high-pass. [pix_tIIR] does temporal filterin using an IIR-filter of settable length. fill with the right coefficients to produce a temporal high-pass. unfortunately the taps in the filter store the images only in the usual precision (e.g. RGBA32), which might yield weird results

in pdp and Gridflow there are surely solutions (which i don't know; just go through the manual), for spatial filtering see [pdp_convolve] (pdp) and [#convolve] (Gridflow).

pdp will work with higher precission (16bit instead of 8bit per channel), and GridFlow will even allow you to use floating point.

mfa.cae. IOhannes