1import torch
2import torchvision.transforms as T
3from torchvision.transforms.functional import InterpolationMode
4from transformers import AutoModel, AutoTokenizer
5from PIL import Image
6
7IMAGENET_MEAN = (0.485, 0.456, 0.406)
8IMAGENET_STD = (0.229, 0.224, 0.225)
9
10def build_transform(input_size):
11 MEAN, STD = IMAGENET_MEAN, IMAGENET_STD
12 transform = T.Compose([
13 T.Lambda(lambda img: img.convert('RGB') if img.mode != 'RGB' else img),
14 T.Resize((input_size, input_size), interpolation=InterpolationMode.BICUBIC),
15 T.ToTensor(),
16 T.Normalize(mean=MEAN, std=STD)
17 ])
18 return transform
19
20def find_closest_aspect_ratio(aspect_ratio, target_ratios, width, height, image_size):
21 best_ratio_diff = float('inf')
22 best_ratio = (1, 1)
23 area = width * height
24 for ratio in target_ratios:
25 target_aspect_ratio = ratio[0] / ratio[1]
26 ratio_diff = abs(aspect_ratio - target_aspect_ratio)
27 if ratio_diff < best_ratio_diff:
28 best_ratio_diff = ratio_diff
29 best_ratio = ratio
30 elif ratio_diff == best_ratio_diff:
31 if area > 0.5 * image_size * image_size * ratio[0] * ratio[1]:
32 best_ratio = ratio
33 return best_ratio
34
35def dynamic_preprocess(image, min_num=1, max_num=12, image_size=448, use_thumbnail=False):
36 orig_width, orig_height = image.size
37 aspect_ratio = orig_width / orig_height
38
39 # calculate the existing image aspect ratio
40 target_ratios = set(
41 (i, j) for n in range(min_num, max_num + 1) for i in range(1, n + 1) for j in range(1, n + 1) if
42 i * j <= max_num and i * j >= min_num)
43 target_ratios = sorted(target_ratios, key=lambda x: x[0] * x[1])
44
45 # find the closest aspect ratio to the target
46 target_aspect_ratio = find_closest_aspect_ratio(
47 aspect_ratio, target_ratios, orig_width, orig_height, image_size)
48
49 # calculate the target width and height
50 target_width = image_size * target_aspect_ratio[0]
51 target_height = image_size * target_aspect_ratio[1]
52 blocks = target_aspect_ratio[0] * target_aspect_ratio[1]
53
54 # resize the image
55 resized_img = image.resize((target_width, target_height))
56 processed_images = []
57 for i in range(blocks):
58 box = (
59 (i % (target_width // image_size)) * image_size,
60 (i // (target_width // image_size)) * image_size,
61 ((i % (target_width // image_size)) + 1) * image_size,
62 ((i // (target_width // image_size)) + 1) * image_size
63 )
64 # split the image
65 split_img = resized_img.crop(box)
66 processed_images.append(split_img)
67 assert len(processed_images) == blocks
68 if use_thumbnail and len(processed_images) != 1:
69 thumbnail_img = image.resize((image_size, image_size))
70 processed_images.append(thumbnail_img)
71 return processed_images
72
73def load_image(image_file, input_size=448, max_num=12):
74 image = Image.open(image_file).convert('RGB')
75 transform = build_transform(input_size=input_size)
76 images = dynamic_preprocess(image, image_size=input_size, use_thumbnail=True, max_num=max_num)
77 pixel_values = [transform(image) for image in images]
78 pixel_values = torch.stack(pixel_values)
79 return pixel_values
80
81# Load model
82MODEL_PATH = "baidu/Qianfan-VL-8B" # or Qianfan-VL-3B, Qianfan-VL-70B
83model = AutoModel.from_pretrained(
84 MODEL_PATH,
85 torch_dtype=torch.bfloat16,
86 trust_remote_code=True,
87 device_map="auto"
88).eval()
89tokenizer = AutoTokenizer.from_pretrained(MODEL_PATH, trust_remote_code=True)
90
91# Load and process image
92pixel_values = load_image("./example/scene_ocr.png").to(torch.bfloat16)
93
94# Inference
95prompt = "<image>请识别图中所有文字"
96with torch.no_grad():
97 response = model.chat(
98 tokenizer,
99 pixel_values=pixel_values,
100 question=prompt,
101 generation_config={"max_new_tokens": 512},
102 verbose=False
103 )
104print(response)