explore exif

shitspotter/util/util_image.py

@@ -35,3 +35,96 @@ def extract_exif_metadata(fpath):
         # TODO: get raw rationals?
         exif['GPSInfo'] = ub.map_keys(GPSTAGS, exif['GPSInfo'])
     return exif
+
+
+def scrub_exif_metadata(fpath, new_fpath):
+    """
+    Test that we can modify EXIF data (e.g. remove GPS or timestamp)
+    without modifying the image.
+
+    Example:
+        >>> # xdoctest: +REQUIRES(module:PIL)
+        >>> # xdoctest: +REQUIRES(module:piexif)
+        >>> from shitspotter.util.util_image import *  # NOQA
+        >>> from shitspotter.util.util_image import *  # NOQA
+        >>> fpath = _dummy_exif_image()
+        >>> new_fpath = fpath.augment(stemsuffix='scrubed')
+        >>> scrub_exif_metadata(fpath, new_fpath)
+        >>> import kwimage
+        >>> data1 = kwimage.imread(fpath)
+        >>> data2 = kwimage.imread(new_fpath)
+        >>> from kwimage.im_io import _imread_exif
+        >>> meta1 = _imread_exif(fpath)
+        >>> meta2 = _imread_exif(new_fpath)
+        >>> assert sum(len(v) for v in meta1.values() if v is not None) > 10
+        >>> assert sum(len(v) for v in meta2.values() if v is not None) == 0
+        >>> assert (data2 == data1).all()
+
+    Ignore:
+        ub.cmd(f'xxd {fpath} > b1.hex', shell=True)
+        ub.cmd(f'xxd {new_fpath} > b2.hex', shell=True)
+        _ = ub.cmd('diff -y b1.hex b2.hex', verbose=3, shell=1)
+    """
+    import piexif
+    import os
+    new_exif = piexif.dump({})
+    raw_bytes = fpath.read_bytes()
+    # old_exif = piexif.load(raw_bytes)
+    piexif.insert(new_exif, raw_bytes, new_file=os.fspath(new_fpath))
+
+
+def _dummy_exif_image():
+    import kwimage
+    from PIL import Image
+    import piexif
+    import ubelt as ub
+    dpath = ub.Path.appdir('shitspotter/tests/exif').ensuredir()
+    fpath = dpath / 'test_1.jpg'
+    # Create a basic EXIF dictionary with dummy camera data
+    # Reference: https://piexif.readthedocs.io/en/latest/functions.html#piexif.dump
+    raw_exif = {
+        "0th": {
+            piexif.ImageIFD.Make: b"FakeMake",
+            piexif.ImageIFD.Model: b"FakeModel",
+            piexif.ImageIFD.Software: b"FakeSoftware 1.0",
+            piexif.ImageIFD.ImageDescription: b"Sample image with dummy EXIF data",
+            piexif.ImageIFD.DateTime: b"2345:01:23 12:34:56",  # YYYY:MM:DD HH:MM:SS format
+        },
+        "Exif": {
+            piexif.ExifIFD.ExposureTime: (1, 60),  # Exposure time (1/60 second)
+            piexif.ExifIFD.FNumber: (28, 10),  # F/2.8 aperture
+            piexif.ExifIFD.ISOSpeedRatings: 100,  # ISO speed
+            piexif.ExifIFD.ShutterSpeedValue: (600, 100),  # Shutter speed in APEX value
+            piexif.ExifIFD.ApertureValue: (280, 100),  # Aperture in APEX value
+            piexif.ExifIFD.BrightnessValue: (5, 1),  # Brightness level
+            piexif.ExifIFD.FocalLength: (50, 1),  # Focal length (50mm)
+            piexif.ExifIFD.LensMake: b"FakeLensMake",  # Lens manufacturer
+            piexif.ExifIFD.LensModel: b"FakeLensModel",  # Lens model
+        },
+        "GPS": {
+            piexif.GPSIFD.GPSLatitudeRef: b"N",
+            piexif.GPSIFD.GPSLatitude: [(40, 1), (0, 1), (0, 1)],  # 40°0'0" N
+            piexif.GPSIFD.GPSLongitudeRef: b"W",
+            piexif.GPSIFD.GPSLongitude: [(74, 1), (0, 1), (0, 1)],  # 74°0'0" W
+            piexif.GPSIFD.GPSAltitudeRef: 0,
+            piexif.GPSIFD.GPSAltitude: (100, 1),  # 100 meters above sea level
+        },
+        # Writing 1st doesnot seem to work with piexif, need to understand why
+        "1st": {},
+        "thumbnail": None,
+        #"1st": {
+        #    piexif.ImageIFD.Make: "Canon",
+        #    piexif.ImageIFD.XResolution: (40, 1),
+        #    piexif.ImageIFD.YResolution: (40, 1),
+        #    piexif.ImageIFD.Software: "piexif"
+        #},
+        #"thumbnail": None,
+        "Interop": {
+            piexif.InteropIFD.InteroperabilityIndex: b"R98",  # Interoperability index
+        }
+    }
+    exif_bytes = piexif.dump(raw_exif)
+    imdata = kwimage.grab_test_image()
+    pil_img = Image.fromarray(imdata)
+    pil_img.save(fpath, exif=exif_bytes)
+    return fpath