update anls metric

PiperOrigin-RevId: 563571566

Author: pix2struct-copybara

pix2struct/metrics.py

@@ -56,11 +56,10 @@ def cider(
 
 
 def anls_metric(target: str, prediction: str, theta: float = 0.5):
-  """Calculates ANLS for DocVQA.
+  """Calculates ANLS for DocVQA and InfographicVQA.
 
-  There does not seem to be an official evaluation script.
-  Public implementation on which this implementation is based:
-  https://github.com/herobd/layoutlmv2/blob/main/eval_docvqa.py#L92
+  Official evaluation script at https://rrc.cvc.uab.es/?ch=17&com=downloads
+  (Infographics VQA Evaluation scripts).
 
   Original paper (see Eq 1): https://arxiv.org/pdf/1907.00490.pdf
 
@@ -75,7 +74,7 @@ def anls_metric(target: str, prediction: str, theta: float = 0.5):
 
   edit_distance = editdistance.eval(target, prediction)
   normalized_ld = edit_distance / max(len(target), len(prediction))
-  return 1 - normalized_ld if normalized_ld < theta else 0
+  return 1 - normalized_ld if normalized_ld <= theta else 0
 
 
 def relaxed_correctness(target: str,