ENH: new light version of lsgrm without aggregation.

OBIA/segmentation.py

@@ -76,9 +76,13 @@ def grm_process_tile(input_image, params : LSGRMParams, tile_width, tile_height,
     op = regionprops(seg['array'][:,:,0].astype(np.int32))
     to_del = []
     for o in op:
-        if not ((tie_lines[0] <= o.bbox[0] < tie_lines[2])
+        if not (tie_lines[0] <= o.bbox[0] < tie_lines[2]
                 and tie_lines[1] <= o.bbox[1] < tie_lines[3]):
-            to_del.append(o.label)
+            # This one to check if a potentially deleted object trespass the overlap area,
+            # in which case it is kept.
+            if not (2*params.margin <= o.bbox[2] < tile_height and
+                    2*params.margin <= o.bbox[3] < tile_width):
+                to_del.append(o.label)
     seg['array'][np.isin(seg['array'], to_del)] = 0
     seg['array'], nlab = label(seg['array'], background=0, connectivity=1, return_num=True)
     seg['array'] = np.ascontiguousarray(seg['array']).astype(float)
@@ -158,23 +162,29 @@ def get_ls_seg_parameter(input_image, roi=None, margin=0, n_proc=None, memory=No
 
     return in_img, n_tiles_x, n_tiles_y, nominal_tw, nominal_th
 
-def lsgrm_light(input_image, params : LSGRMParams, out_seg, n_proc=None, memory=None, roi=None, force_parallel=False):
+def lsgrm_light(input_image, params : LSGRMParams, out_seg, n_proc=None, memory=None,
+                roi=None, force_parallel=False, remove_tiles_if_useless=True):
     # Check output file type
     ext = os.path.splitext(out_seg)[-1]
-    if ext in ['.tif']:
+    if ext == '.vrt':
+        mode = 'vrt'
+    elif ext in ['.tif']:
         mode = 'raster'
-    elif ext in ['.shp', '.gpkg', 'gml']:
+    elif ext in ['.shp', '.gml', '.gpkg']:
         mode = 'vector'
-    elif ext in ['.vrt']:
-        mode = 'vrt'
     else:
-        raise ValueError('Output type {} not recognized/supported.'.format(ext))
+        raise ValueError('Output type {} not supported.'.format(ext))
 
     in_img, n_tiles_x, n_tiles_y, nominal_tw, nominal_th = get_ls_seg_parameter(input_image, roi, params.margin, n_proc,
                                                                         memory, force_parallel)
 
+    print('[INFO] Using a layout of {} x {} tiles.'.format(n_tiles_x,n_tiles_y))
+    print('[INFO] Nominal tile size w/margin: {} x {} pixels'.format(nominal_tw+2*params.margin,
+                                                                     nominal_th+2*params.margin))
+
     if (n_tiles_x == 1 and n_tiles_y == 1):
         # Fallback to classical GRM
+        print('[INFO] Fallback to one-tile GRM.')
         grm = otb.Registry.CreateApplication('GenericRegionMerging')
         grm.SetParameterInputImage('in', in_img.GetParameterOutputImage('out'))
         grm.SetParameterFloat('threshold', params.threshold)
@@ -198,9 +208,26 @@ def lsgrm_light(input_image, params : LSGRMParams, out_seg, n_proc=None, memory=
                     tile.nodata = 0
             cumul_label += l
 
+        print('[INFO] Output mode {}.'.format(mode))
         if mode == 'vrt':
             vrtopt = gdal.BuildVRTOptions(separate=False, srcNodata=0, VRTNodata=0)
             gdal.BuildVRT(out_seg, [x[0] for x in out_tiles], options=vrtopt)
+        elif mode in ['raster', 'vector']:
+            mos = otb.Registry.CreateApplication('Mosaic')
+            mos.SetParameterStringList('il', [x[0] for x in out_tiles])
+            mos.SetParameterInt('nodata', 0)
+            if mode == 'raster':
+                mos.SetParameterOutputImagePixelType('out', otb.ImagePixelType_uint32)
+                mos.SetParameterString('out', out_seg)
+                mos.ExecuteAndWriteOutput()
+            elif mode == 'vector':
+                mos.Execute()
+                vec = otb.Registry.CreateApplication('SimpleVectorization')
+                vec.SetParameterInputImage('in', mos.GetParameterOutputImage('out'))
+                vec.SetParameterString('out', out_seg)
+                vec.ExecuteAndWriteOutput()
+            if remove_tiles_if_useless:
+                [os.remove(x[0]) for x in out_tiles]
 
     return out_seg