Fixed GPU detection on CPU only environment (#4711)

### What problem does this PR solve?

Fixed GPU detection on CPU only environment. Close #4692

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

deepdoc/vision/ocr.py

@@ -27,6 +27,7 @@ from . import operators
 import math
 import numpy as np
 import cv2
+import torch
 import onnxruntime as ort
 
 from .postprocess import build_post_process
@@ -80,7 +81,7 @@ def load_model(model_dir, nm):
     # https://github.com/microsoft/onnxruntime/issues/9509#issuecomment-951546580
     # Shrink GPU memory after execution
     run_options = ort.RunOptions()
-    if ort.get_device() == "GPU":
+    if torch.cuda.is_available():
         cuda_provider_options = {
             "device_id": 0, # Use specific GPU
             "gpu_mem_limit": 512 * 1024 * 1024, # Limit gpu memory

deepdoc/vision/recognizer.py

@@ -21,7 +21,7 @@ import numpy as np
 import cv2
 from copy import deepcopy
 
-
+import torch
 import onnxruntime as ort
 from huggingface_hub import snapshot_download
 
@@ -64,7 +64,7 @@ class Recognizer(object):
         # Shrink GPU memory after execution
         self.run_options = ort.RunOptions()
 
-        if ort.get_device() == "GPU":
+        if torch.cuda.is_available():
             options = ort.SessionOptions()
             options.enable_cpu_mem_arena = False
             cuda_provider_options = {