Combine road hypotheses from two resolution levels.
combine_roads_xld combines road hypotheses obtained from two different resolution levels. The algorithm selects only those hypotheses which mutually support each other in both resolution levels. The parameters EdgePolygons, ModParallels and ExtParallels correspond to the road hypotheses from the highest resolution level. The parameter CenterLines is the result of road extraction in a lower resolution level. Those of the polygons EdgePolygons are returned for which evidence of being roadsides is found in both resolution levels. The parameters MaxAngleParallel and MaxAngleColinear determine the angle, that may be formed by two parallel collinear line segments, respectively. The parameters MaxDistanceParallel and MaxDistanceColinear determine the maximum allowed distance of two parallel or colliear line segments, respectively. The combination is done using a number of rules.
|
EdgePolygons (input_object) |
xld_poly-array -> object |
| XLD polygons to be examined. | |
|
ModParallels (input_object) |
xld_mod_para-array -> object |
| Modified parallels obtained from EdgePolygons. | |
|
ExtParallels (input_object) |
xld_ext_para-array -> object |
| Extended parallels obtained from EdgePolygons. | |
|
CenterLines (input_object) |
xld_poly-array -> object |
| Road-center-line polygons to be examined. | |
|
RoadSides (output_object) |
xld_poly-array -> object |
| Roadsides found. | |
|
MaxAngleParallel (input_control) |
angle.rad -> real / integer |
| Maximum angle between two parallel line segments. | |
| Default value: 0.523598775598 | |
| Suggested values: 0.349065850399, 0.523598775598, 0.6981317008 | |
| Restriction: (0 <= MaxAngleParallel) <= (pi / 2) | |
|
MaxAngleColinear (input_control) |
angle.rad -> real / integer |
| Maximum angle between two collinear line segments. | |
| Default value: 0.261799387799 | |
| Suggested values: 0.174532925199, 0.261799387799, 0.349065850399 | |
| Restriction: (0 <= MaxAngleColinear) <= (pi / 2) | |
|
MaxDistanceParallel (input_control) |
real -> real / integer |
| Maximum distance between two parallel line segments. | |
| Default value: 40 | |
| Suggested values: 20, 30, 40, 50, 60 | |
| Restriction: MaxDistanceParallel > 0 | |
|
MaxDistanceColinear (input_control) |
real -> real / integer |
| Maximum distance between two collinear line segments. | |
| Default value: 40 | |
| Suggested values: 20, 30, 40, 50, 60 | |
| Restriction: MaxDistanceColinear > 0 | |
combine_roads_xld is processed under mutual exclusion against itself and without parallelization.
mod_parallels_xld, gen_polygons_xld, affine_trans_contour_xld
get_polygon_xld, get_lines_xld
lines_gauss, lines_facet, get_channel_info, edges_sub_pix
C. Steger, C. Glock, W. Eckstein, H. Mayer, B. Radig; "Model-based Road Extraction from Images"; in "Automatic Extraction of Man-Made Objects from Aerial and Space Images"; A. Gruen, O. Kuebler, P. Agouris (Editors); Birkhäuser Verlag (1995), pp. 275-284.
C. Heipke, C. Steger, R. Multhammer; "A Hierarchical Approach to Automatic Road Extraction from Aerial Imagery"; in "Integrating Photogrammetric Techniques with Scene Analysis and Machine Vision II"; D. M. McKeown, Jr., I. J. Dowman (Editors); Proc. SPIE 2486 (1995), pp. 222-231.
Sub-pixel operators
