89 lines
3.4 KiB
Python
89 lines
3.4 KiB
Python
import io
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from pathlib import Path
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import numpy as np
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import torch
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from PIL import ExifTags, Image, ImageCms, ImageOps
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from PIL.Image import Image as PilImage
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def open_image_as_srgb(image_path: str | Path | io.BytesIO) -> PilImage:
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"""
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Opens an image file, applies rotation (if it's set in metadata) and converts it
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to the sRGB color space respecting the original image color space .
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Args:
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image_path: Path to the image file
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Returns:
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PIL Image in sRGB color space
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"""
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exif_colorspace_srgb = 1
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with Image.open(image_path) as img_raw:
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img = ImageOps.exif_transpose(img_raw)
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input_icc_profile = img.info.get("icc_profile")
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# Try to convert to sRGB if the image has ICC profile metadata
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srgb_profile = ImageCms.createProfile(colorSpace="sRGB")
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if input_icc_profile is not None:
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input_profile = ImageCms.ImageCmsProfile(io.BytesIO(input_icc_profile))
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srgb_img = ImageCms.profileToProfile(img, input_profile, srgb_profile, outputMode="RGB")
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else:
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# Try fall back to checking EXIF
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exif_data = img.getexif()
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if exif_data is not None:
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# Assume sRGB if no ICC profile and EXIF has no ColorSpace tag
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color_space_value = exif_data.get(ExifTags.Base.ColorSpace.value)
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if color_space_value is not None and color_space_value != exif_colorspace_srgb:
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raise ValueError(
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"Image has colorspace tag in EXIF but it isn't set to sRGB,"
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" conversion is not supported."
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f" EXIF ColorSpace tag value is {color_space_value}",
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)
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srgb_img = img.convert("RGB")
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# Set sRGB profile in metadata since now the image is assumed to be in sRGB.
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srgb_profile_data = ImageCms.ImageCmsProfile(srgb_profile).tobytes()
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srgb_img.info["icc_profile"] = srgb_profile_data
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return srgb_img
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def save_image(image_tensor: torch.Tensor, output_path: Path | str) -> None:
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"""Save an image tensor to a file.
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Args:
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image_tensor: Image tensor of shape [C, H, W] or [C, 1, H, W] in range [0, 1] or [0, 255].
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C must be 3 (RGB).
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output_path: Path to save the image (any PIL-supported format, e.g., .png or .jpg)
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"""
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output_path = Path(output_path)
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output_path.parent.mkdir(parents=True, exist_ok=True)
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# Handle [C, 1, H, W] format (single frame from video tensor)
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if image_tensor.ndim == 4:
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# Squeeze frame dimension: [C, 1, H, W] -> [C, H, W]
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if image_tensor.shape[1] == 1:
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image_tensor = image_tensor.squeeze(1)
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else:
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raise ValueError(f"Expected single-frame tensor with shape [C, 1, H, W], got shape {image_tensor.shape}")
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if image_tensor.ndim != 3:
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raise ValueError(f"Expected 3D tensor [C, H, W], got {image_tensor.ndim}D tensor")
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if image_tensor.shape[0] != 3:
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raise ValueError(f"Expected 3 channels (RGB), got {image_tensor.shape[0]} channels")
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# Normalize to [0, 255] uint8
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if torch.is_floating_point(image_tensor) and image_tensor.max() <= 1.0:
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image_tensor = image_tensor * 255
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# Clamp to valid uint8 range to prevent overflow
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image_tensor = image_tensor.clamp(0, 255)
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# [C, H, W] -> [H, W, C]
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image_np: np.ndarray = image_tensor.permute(1, 2, 0).to(torch.uint8).cpu().numpy()
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# Save using PIL
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Image.fromarray(image_np).save(output_path)
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