|
| 1 | +# copy from https://huggingface.co/OpenGVLab/InternVL3-1B |
| 2 | +import torch |
| 3 | +import torchvision.transforms as T |
| 4 | +from PIL import Image |
| 5 | +from torchvision.transforms.functional import InterpolationMode |
| 6 | + |
| 7 | +IMAGENET_MEAN = (0.485, 0.456, 0.406) |
| 8 | +IMAGENET_STD = (0.229, 0.224, 0.225) |
| 9 | + |
| 10 | + |
| 11 | +def build_transform(input_size): |
| 12 | + MEAN, STD = IMAGENET_MEAN, IMAGENET_STD |
| 13 | + transform = T.Compose( |
| 14 | + [ |
| 15 | + T.Lambda(lambda img: img.convert("RGB") if img.mode != "RGB" else img), |
| 16 | + T.Resize((input_size, input_size), interpolation=InterpolationMode.BICUBIC), |
| 17 | + T.ToTensor(), |
| 18 | + T.Normalize(mean=MEAN, std=STD), |
| 19 | + ] |
| 20 | + ) |
| 21 | + return transform |
| 22 | + |
| 23 | + |
| 24 | +def find_closest_aspect_ratio(aspect_ratio, target_ratios, width, height, image_size): |
| 25 | + best_ratio_diff = float("inf") |
| 26 | + best_ratio = (1, 1) |
| 27 | + area = width * height |
| 28 | + for ratio in target_ratios: |
| 29 | + target_aspect_ratio = ratio[0] / ratio[1] |
| 30 | + ratio_diff = abs(aspect_ratio - target_aspect_ratio) |
| 31 | + if ratio_diff < best_ratio_diff: |
| 32 | + best_ratio_diff = ratio_diff |
| 33 | + best_ratio = ratio |
| 34 | + elif ratio_diff == best_ratio_diff: |
| 35 | + if area > 0.5 * image_size * image_size * ratio[0] * ratio[1]: |
| 36 | + best_ratio = ratio |
| 37 | + return best_ratio |
| 38 | + |
| 39 | + |
| 40 | +def dynamic_preprocess( |
| 41 | + image, min_num=1, max_num=12, image_size=448, use_thumbnail=False |
| 42 | +): |
| 43 | + orig_width, orig_height = image.size |
| 44 | + aspect_ratio = orig_width / orig_height |
| 45 | + |
| 46 | + # calculate the existing image aspect ratio |
| 47 | + target_ratios = set( |
| 48 | + (i, j) |
| 49 | + for n in range(min_num, max_num + 1) |
| 50 | + for i in range(1, n + 1) |
| 51 | + for j in range(1, n + 1) |
| 52 | + if i * j <= max_num and i * j >= min_num |
| 53 | + ) |
| 54 | + target_ratios = sorted(target_ratios, key=lambda x: x[0] * x[1]) |
| 55 | + |
| 56 | + # find the closest aspect ratio to the target |
| 57 | + target_aspect_ratio = find_closest_aspect_ratio( |
| 58 | + aspect_ratio, target_ratios, orig_width, orig_height, image_size |
| 59 | + ) |
| 60 | + |
| 61 | + # calculate the target width and height |
| 62 | + target_width = image_size * target_aspect_ratio[0] |
| 63 | + target_height = image_size * target_aspect_ratio[1] |
| 64 | + blocks = target_aspect_ratio[0] * target_aspect_ratio[1] |
| 65 | + |
| 66 | + # resize the image |
| 67 | + resized_img = image.resize((target_width, target_height)) |
| 68 | + processed_images = [] |
| 69 | + for i in range(blocks): |
| 70 | + box = ( |
| 71 | + (i % (target_width // image_size)) * image_size, |
| 72 | + (i // (target_width // image_size)) * image_size, |
| 73 | + ((i % (target_width // image_size)) + 1) * image_size, |
| 74 | + ((i // (target_width // image_size)) + 1) * image_size, |
| 75 | + ) |
| 76 | + # split the image |
| 77 | + split_img = resized_img.crop(box) |
| 78 | + processed_images.append(split_img) |
| 79 | + assert len(processed_images) == blocks |
| 80 | + if use_thumbnail and len(processed_images) != 1: |
| 81 | + thumbnail_img = image.resize((image_size, image_size)) |
| 82 | + processed_images.append(thumbnail_img) |
| 83 | + return processed_images |
| 84 | + |
| 85 | + |
| 86 | +def load_image(image_file, input_size=448, max_num=12): |
| 87 | + image = Image.open(image_file).convert("RGB") |
| 88 | + transform = build_transform(input_size=input_size) |
| 89 | + images = dynamic_preprocess( |
| 90 | + image, image_size=input_size, use_thumbnail=True, max_num=max_num |
| 91 | + ) |
| 92 | + pixel_values = [transform(image) for image in images] |
| 93 | + pixel_values = torch.stack(pixel_values) |
| 94 | + return pixel_values |
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