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Computer Vision: Edge detect project

Avatar for Jamie Ly Jamie Ly
October 09, 2010

Computer Vision: Edge detect project

Results of an edge detection project are discussed.

Avatar for Jamie Ly

Jamie Ly

October 09, 2010
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  1. •Standard approach ◦ Local maxima ◦ Hysteresis •Different Thresholds for

    different images ◦ Threshold is a function of average gradient value and standard deviation of gradient value ◦ Threshold= mean + factor*std. deviation
  2. •2 steps ◦ Find all local maximas. ◦ Keep only

    those maximas which are above the threshold. •Two matrices ◦ LM_H = (Mag_q > Mag_r or q = r) and (Mag_q > Mag_p or q = p) ◦ LM_L = LM_H | Mag_q > thresh_mag
  3. •Mask_s = Mag_s > threshold_hys and LM_L •Mask_os = Mag_os

    > threshold_hys and LM_L •Hysteresis = LM_H and Mask_s and Mask_os
  4. •Understand the algorithm •Ask more questions early •Start early (did

    this!) •Try the way you know first. Optimize later. •Edges too thick!