open README.md with unicode (to support Hugging Face emoji); fix various typos (#218)

(close #217, #66, #67, #69, #91, #126, #127, #145)

sam2/modeling/position_encoding.py

@@ -16,7 +16,7 @@ from torch import nn
 class PositionEmbeddingSine(nn.Module):
     """
     This is a more standard version of the position embedding, very similar to the one
-    used by the Attention is all you need paper, generalized to work on images.
+    used by the Attention Is All You Need paper, generalized to work on images.
     """
 
     def __init__(

sam2/modeling/sam2_base.py

@@ -642,7 +642,7 @@ class SAM2Base(torch.nn.Module):
                 pix_feat_with_mem = pix_feat_with_mem.permute(1, 2, 0).view(B, C, H, W)
                 return pix_feat_with_mem
 
-            # Use a dummy token on the first frame (to avoid emtpy memory input to tranformer encoder)
+            # Use a dummy token on the first frame (to avoid empty memory input to tranformer encoder)
             to_cat_memory = [self.no_mem_embed.expand(1, B, self.mem_dim)]
             to_cat_memory_pos_embed = [self.no_mem_pos_enc.expand(1, B, self.mem_dim)]