make sure work without cuda

src/orisys/Stitcher.py

@@ -443,7 +443,7 @@ class Stitcher:
         
         h, w = img.shape[:2]
         n_boxes = 0
-        bk_thresh = 35  # initial black threshold
+        bk_thresh = 0  # initial black threshold
         bk_thresh_step = 5
         bk_thresh_max = 100
 
@@ -461,7 +461,8 @@ class Stitcher:
             kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (k, k))
             mask = cv2.morphologyEx(mask, cv2.MORPH_OPEN, kernel, iterations=1)
             mask = cv2.morphologyEx(mask, cv2.MORPH_CLOSE, kernel, iterations=2)
-
+            # cv2.imshow("mask", mask)
+            # cv2.waitKey(0)
             # find contours of candidate regions
             contours, _ = cv2.findContours(mask, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)