diff --git a/Article/method.tex b/Article/method.tex index 4a5aeda5f2e30a307bc52cea7093759e55726945..0383ebcaecc8be8bcf61666bc7f49f6f30531ec6 100755 --- a/Article/method.tex +++ b/Article/method.tex @@ -227,14 +227,19 @@ This strategy provides a first quick analysis of the local context before extracting the segment and contributes to notably stabilize the overall process. -When selecting candidates for the fine detection stage, an option is left -to also reject points with a gradient vector in an opposite direction to -the gradient vector of the blurred segment start point. -In that case, called {\it edge selection mode}, all the blurred segment -points have the same direction. -If they are not rejected, points with opposite gradients are aggregated -into a same blurred segment, allowing the detection of the two opposite -edges of a thin straight object. This is called {\it line selection mode}. +When selecting candidates for the fine detection stage, an option, called +{\it edge selection mode}, is left to filter the points according to their +gradient direction. +In {\it main edge selection mode}, only the points with a gradient vector +in the same direction as the start point gradient vector are added to the +blurred segment. +In {\it opposite edge selection mode}, only the points with an opposite +gradient vector direction are kept. +In {\it line selection mode} this filter is not applied, and all the +candidate points are aggregated into a same blurred segment, whatever the +direction of their gradient vector. +This mode allows the detection of the two opposite edges of a thin straight +object. This distinction is illustrated on \RefFig{fig:edgeDir}. \begin{figure}[h] @@ -285,10 +290,8 @@ blurred segment extension in the fine tracking step. Multiple detections of the same edge are thus avoided. In edge selection mode (\RefFig{fig:edgeDir} b), the multi-detection -algorithm is executed twice. -In the second run, the start point is rejected and only candidate points -with opposite gradient direction are considered to extend the blurred -segment. +algorithm is executed twice, first in main edge selection mode, then +in opposite edge selection mode. %Beyond the possible detection of a large set of edges at once, the %multi-detection allows the detection of some unaccessible edges in