Figure 2From: Automatic tracking of cells for video microscopy in patch clamp experiments Filters and types of matching used by SURF. (A), (B), and (C) Approximation of Gaussian second order partial derivatives using box filters: D x y in xy-direction, D x x in x-direction and y-direction in D y y , respectively, with increased kernel size from (9×9) to (15×15) in (C). (D) Haar wavelet filters in response to dx (top) and dy (bottom) directions with (σ=2s) kernel size. (E) Candidate interest points to perform matching are combinations between circular areas with the same contrast and, the oposite are not considered.Back to article page