fix OverflowError in text_visual func (#14758)

Author: GreatV

tools/infer/utility.py

@@ -621,7 +621,7 @@ def text_visual(
         ), "The number of txts and corresponding scores must match"
 
     def create_blank_img():
-        blank_img = np.ones(shape=[img_h, img_w], dtype=np.int8) * 255
+        blank_img = np.ones(shape=[img_h, img_w], dtype=np.uint8) * 255
         blank_img[:, img_w - 1 :] = 0
         blank_img = Image.fromarray(blank_img).convert("RGB")
         draw_txt = ImageDraw.Draw(blank_img)