Replicate changes from open-edge-platform/training_extensions#2452 (#132)

* Prevent too small explain map size in tiling

* Fix zero saliency map problem in cpp tiler

Author: sovrasov

model_api/cpp/tilers/src/detection.cpp

@@ -161,8 +161,8 @@ ov::Tensor DetectionTiler::merge_saliency_maps(const std::vector<std::unique_ptr
     size_t map_h = image_saliency_map.get_shape()[shape_shift + 1];
     size_t map_w = image_saliency_map.get_shape()[shape_shift + 2];
 
-    float ratio_h = static_cast<float>(map_h) / tile_size;
-    float ratio_w = static_cast<float>(map_w) / tile_size;
+    float ratio_h = static_cast<float>(map_h) / std::min(tile_size, static_cast<size_t>(image_size.height));
+    float ratio_w = static_cast<float>(map_w) / std::min(tile_size, static_cast<size_t>(image_size.width));
 
     size_t image_map_h = static_cast<size_t>(image_size.height * ratio_h);
     size_t image_map_w = static_cast<size_t>(image_size.width * ratio_w);

model_api/python/openvino/model_api/tilers/detection.py

@@ -167,7 +167,9 @@ def _merge_saliency_maps(self, saliency_maps, shape, tiles_coords):
         map_h, map_w = image_saliency_map.shape[1:]
 
         image_h, image_w, _ = shape
-        ratio = map_h / self.tile_size, map_w / self.tile_size
+        ratio = map_h / min(image_h, self.tile_size), map_w / min(
+            image_w, self.tile_size
+        )
 
         image_map_h = int(image_h * ratio[0])
         image_map_w = int(image_w * ratio[1])