mapillary_download/lib/exif.py
2023-09-10 21:02:33 +02:00

386 lines
12 KiB
Python

#!/usr/bin/env python
import os
import sys
import exifread
import datetime
from lib.geo import normalize_bearing
sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__), "..")))
def eval_frac(value):
return float(value.num) / float(value.den)
def exif_gps_fields():
'''
GPS fields in EXIF
'''
return [
["GPS GPSLongitude", "EXIF GPS GPSLongitude"],
["GPS GPSLatitude", "EXIF GPS GPSLatitude"]
]
def exif_datetime_fields():
'''
Date time fields in EXIF
'''
return [["EXIF DateTimeOriginal",
"Image DateTimeOriginal",
"EXIF DateTimeDigitized",
"Image DateTimeDigitized",
"EXIF DateTime"
"Image DateTime",
"GPS GPSDate",
"EXIF GPS GPSDate",
"EXIF DateTimeModified"]]
def format_time(time_string):
'''
Format time string with invalid time elements in hours/minutes/seconds
Format for the timestring needs to be "%Y_%m_%d_%H_%M_%S"
e.g. 2014_03_31_24_10_11 => 2014_04_01_00_10_11
'''
data = time_string.split("_")
hours, minutes, seconds = int(data[3]), int(data[4]), int(data[5])
date = datetime.datetime.strptime("_".join(data[:3]), "%Y_%m_%d")
date_time = date + datetime.timedelta(hours=hours, minutes=minutes, seconds=seconds)
return date_time
def gps_to_decimal(values, reference):
sign = 1 if reference in 'NE' else -1
degrees = eval_frac(values[0])
minutes = eval_frac(values[1])
seconds = eval_frac(values[2])
return sign * (degrees + minutes / 60 + seconds / 3600)
def get_float_tag(tags, key):
if key in tags:
return float(tags[key].values[0])
else:
return None
def get_frac_tag(tags, key):
if key in tags:
return eval_frac(tags[key].values[0])
else:
return None
def extract_exif_from_file(fileobj):
if isinstance(fileobj, (str, unicode)):
with open(fileobj) as f:
exif_data = EXIF(f)
else:
exif_data = EXIF(fileobj)
d = exif_data.extract_exif()
return d
def required_fields():
return exif_gps_fields() + exif_datetime_fields()
def verify_exif(filename):
'''
Check that image file has the required EXIF fields.
Incompatible files will be ignored server side.
'''
# required tags in IFD name convention
required_exif = required_fields()
exif = EXIF(filename)
required_exif_exist = exif.fields_exist(required_exif)
return required_exif_exist
def verify_mapillary_tag(filename):
'''
Check that image file has the required Mapillary tag
'''
return EXIF(filename).mapillary_tag_exists()
def is_image(filename):
return filename.lower().endswith(('jpg', 'jpeg', 'png', 'tif', 'tiff', 'pgm', 'pnm', 'gif'))
class EXIF:
'''
EXIF class for reading exif from an image
'''
def __init__(self, filename, details=False):
'''
Initialize EXIF object with FILE as filename or fileobj
'''
self.filename = filename
if type(filename) == str:
with open(filename, 'rb') as fileobj:
self.tags = exifread.process_file(fileobj, details=details)
else:
self.tags = exifread.process_file(filename, details=details)
def _extract_alternative_fields(self, fields, default=None, field_type=float):
'''
Extract a value for a list of ordered fields.
Return the value of the first existed field in the list
'''
for field in fields:
if field in self.tags:
if field_type is float:
value = eval_frac(self.tags[field].values[0])
if field_type is str:
value = str(self.tags[field].values)
if field_type is int:
value = int(self.tags[field].values[0])
return value, field
return default, None
def exif_name(self):
'''
Name of file in the form {lat}_{lon}_{ca}_{datetime}_{filename}
'''
lon, lat = self.extract_lon_lat()
ca = self.extract_direction()
if ca is None:
ca = 0
ca = int(ca)
date_time = self.extract_capture_time()
date_time = date_time.strftime("%Y-%m-%d-%H-%M-%S-%f")
date_time = date_time[:-3]
filename = '{}_{}_{}_{}_{}'.format(lat, lon, ca, date_time, os.path.basename(self.filename))
return filename
def extract_altitude(self):
'''
Extract altitude
'''
fields = ['GPS GPSAltitude', 'EXIF GPS GPSAltitude']
altitude, _ = self._extract_alternative_fields(fields, 0, float)
return altitude
def extract_capture_time(self):
'''
Extract capture time from EXIF
return a datetime object
TODO: handle GPS DateTime
'''
time_string = exif_datetime_fields()[0]
capture_time, time_field = self._extract_alternative_fields(time_string, 0, str)
# if "GPSDate" in time_field:
# return self.extract_gps_time()
if capture_time is 0:
# try interpret the filename
try:
capture_time = datetime.datetime.strptime(os.path.basename(self.filename)[:-4]+'000', '%Y_%m_%d_%H_%M_%S_%f')
except:
pass
else:
capture_time = capture_time.replace(" ", "_")
capture_time = capture_time.replace(":", "_")
capture_time = "_".join(["{0:02d}".format(int(ts)) for ts in capture_time.split("_") if ts.isdigit()])
capture_time = format_time(capture_time)
sub_sec = self.extract_subsec()
capture_time = capture_time + datetime.timedelta(seconds=float(sub_sec)/10**len(str(sub_sec)))
return capture_time
def extract_direction(self):
'''
Extract image direction (i.e. compass, heading, bearing)
'''
fields = ['GPS GPSImgDirection',
'EXIF GPS GPSImgDirection',
'GPS GPSTrack',
'EXIF GPS GPSTrack']
direction, _ = self._extract_alternative_fields(fields)
if direction is not None:
direction = normalize_bearing(direction, check_hex=True)
return direction
def extract_dop(self):
'''
Extract dilution of precision
'''
fields = ['GPS GPSDOP', 'EXIF GPS GPSDOP']
dop, _ = self._extract_alternative_fields(fields)
return dop
def extract_geo(self):
'''
Extract geo-related information from exif
'''
altitude = self.extract_altitude()
dop = self.extract_dop()
lon, lat = self.extract_lon_lat()
d = {}
if lon is not None and lat is not None:
d['latitude'] = lat
d['longitude'] = lon
if altitude is not None:
d['altitude'] = altitude
if dop is not None:
d['dop'] = dop
return d
def extract_gps_time(self):
'''
Extract timestamp from GPS field.
'''
gps_date_field = "GPS GPSDate"
gps_time_field = "GPS GPSTimeStamp"
gps_time = 0
if gps_date_field in self.tags and gps_time_field in self.tags:
date = str(self.tags[gps_date_field].values).split(":")
t = self.tags[gps_time_field]
gps_time = datetime.datetime(
year=int(date[0]),
month=int(date[1]),
day=int(date[2]),
hour=int(eval_frac(t.values[0])),
minute=int(eval_frac(t.values[1])),
second=int(eval_frac(t.values[2])),
)
microseconds = datetime.timedelta(microseconds=int( (eval_frac(t.values[2])%1) *1e6))
gps_time += microseconds
return gps_time
def extract_exif(self):
'''
Extract a list of exif infos
'''
width, height = self.extract_image_size()
make, model = self.extract_make(), self.extract_model()
orientation = self.extract_orientation()
geo = self.extract_geo()
capture = self.extract_capture_time()
direction = self.extract_direction()
d = {
'width': width,
'height': height,
'orientation': orientation,
'direction': direction,
'make': make,
'model': model,
'capture_time': capture
}
d['gps'] = geo
return d
def extract_image_size(self):
'''
Extract image height and width
'''
width, _ = self._extract_alternative_fields(['Image ImageWidth', 'EXIF ExifImageWidth'], -1, int)
height, _ = self._extract_alternative_fields(['Image ImageLength', 'EXIF ExifImageLength'], -1, int)
return width, height
def extract_image_description(self):
'''
Extract image description
'''
description, _ = self._extract_alternative_fields(['Image ImageDescription'], "{}", str)
return description
def extract_lon_lat(self):
if 'GPS GPSLatitude' in self.tags and 'GPS GPSLatitude' in self.tags:
lat = gps_to_decimal(self.tags['GPS GPSLatitude'].values,
self.tags['GPS GPSLatitudeRef'].values)
lon = gps_to_decimal(self.tags['GPS GPSLongitude'].values,
self.tags['GPS GPSLongitudeRef'].values)
elif 'EXIF GPS GPSLatitude' in self.tags and 'EXIF GPS GPSLatitude' in self.tags:
lat = gps_to_decimal(self.tags['EXIF GPS GPSLatitude'].values,
self.tags['EXIF GPS GPSLatitudeRef'].values)
lon = gps_to_decimal(self.tags['EXIF GPS GPSLongitude'].values,
self.tags['EXIF GPS GPSLongitudeRef'].values)
else:
lon, lat = None, None
return lon, lat
def extract_make(self):
'''
Extract camera make
'''
fields = ['EXIF LensMake', 'Image Make']
make, _ = self._extract_alternative_fields(fields, default='none', field_type=str)
return make
def extract_model(self):
'''
Extract camera model
'''
fields = ['EXIF LensModel', 'Image Model']
model, _ = self._extract_alternative_fields(fields, default='none', field_type=str)
return model
def extract_orientation(self):
'''
Extract image orientation
'''
fields = ['Image Orientation']
orientation, _ = self._extract_alternative_fields(fields, default=1, field_type=int)
if orientation not in [1, 3, 6, 8]:
return 1
return orientation
def extract_subsec(self):
'''
Extract microseconds
'''
fields = [
'Image SubSecTimeOriginal',
'EXIF SubSecTimeOriginal',
'Image SubSecTimeDigitized',
'EXIF SubSecTimeDigitized',
'Image SubSecTime',
'EXIF SubSecTime'
]
sub_sec, _ = self._extract_alternative_fields(fields, default=0, field_type=str)
sub_sec = int(sub_sec)
return sub_sec
def fields_exist(self, fields):
'''
Check existence of a list fields in exif
'''
for rexif in fields:
vflag = False
for subrexif in rexif:
if subrexif in self.tags:
vflag = True
if not vflag:
print("Missing required EXIF tag: {0} for image {1}".format(rexif[0], self.filename))
return False
return True
def mapillary_tag_exists(self):
'''
Check existence of Mapillary tag
'''
description_tag = "Image ImageDescription"
if description_tag in self.tags:
if "MAPSequenceUUID" in self.tags[description_tag].values:
return True
return False