A new algorithm for tracing nests of interconnected contours

Image-based adaptive crosshatch toolpath generation for laminated object manufacturing

“…As mentioned previously, two cutting activities (profile cutting and crosshatching) are required for a layer to be completed with LOM and a cutting pattern on each layer can be seen as the combination of the images of the patterns of the two cutting activities on that particular layer as illustrated in Figure 1. The profile cutting path, a vector movement, can be extracted from the boundary contour of the layer by using available contouring techniques such as the one proposed by Kuagoolkijgarn et al (2010). The crosshatch toolpath, a raster movement, is proposed in this research to be achieved by intersecting the image of a waste area on the layer with the image of a predetermined crosshatch pattern as illustrated in Figure 2, instead of calculating intersection points between the pattern and layer contour.…”

“…It is done by projecting all contours onto the same plane and searching for the first pixels from the four directions in order to establish a rectangular boundary that passes through these pixels. The bounding box is adjusted to be two pixels wider and longer to support the finding of the outermost contour on the projected plane because the contour tracing algorithm by Kuagoolkijgarn et al (2010) requires considering pixels on a contour be surrounded by eight pixels in a neighbourhood.…”