Use ascii instead of unicode and remove uncessary index

Signed-off-by: Bruce Hashemian <[email protected]>

Author: bhashemian

monai/apps/pathology/transforms/stain/array.py

@@ -87,9 +87,9 @@ def _deconvolution_extract_stain(self, image: np.ndarray) -> np.ndarray:
         # a heuristic to make the vector corresponding to hematoxylin first and the one corresponding to eosin second
         # Hematoxylin: high blue, lower red (low R/B ratio)
         # Eosin: high red, lower blue (high R/B ratio)
-        ε = np.finfo(np.float32).eps
-        v_min_rb_ratio = v_min[0, 0] / (v_min[2, 0] + ε)
-        v_max_rb_ratio = v_max[0, 0] / (v_max[2, 0] + ε)
+        eps = np.finfo(np.float32).eps
+        v_min_rb_ratio = v_min[0] / (v_min[2] + eps)
+        v_max_rb_ratio = v_max[0] / (v_max[2] + eps)
         if v_min_rb_ratio < v_max_rb_ratio:
             he = np.array((v_min[:, 0], v_max[:, 0]), dtype=np.float32).T
         else: