使用PHP exif_read_data获取照片的“拍摄日期”而不是“修改日期”

Question

I'm retrieving the creation date from a photo with exif_read_data PHP function (see the code below.) The dates retrieved from photos that haven't been modified return "Date Taken". Those that have been modified - "Date Modified". Is there a way to get the date a photo was taken, ignoring the "Date Modified" field?

$exif_data = exif_read_data ($filename);
if (!empty($exif_data['DateTime'])) {
    $exif_date = $exif_data['DateTime'];
}

Thank you.

Edit: I think $exif_data['DateTime'] uses the first available date field. Since unmodified images had the same value for "Date Modified" and "Date Taken" it was always retrieving "Date Modified" in my case.

Answer 1

echo "test1.jpg:<br />
";
$exif = exif_read_data('tests/test1.jpg', 'IFD0');
echo $exif===false ? "No header data found.<br />
" : "Image contains headers<br />
";

$exif = exif_read_data('tests/test2.jpg', 0, true);
echo "test2.jpg:<br />
";
foreach ($exif as $key => $section) {
foreach ($section as $name => $val) {
    echo "$key.$name: $val<br />
";
}
}

will output

test1.jpg:
No header data found.
test2.jpg:
FILE.FileName: test2.jpg
FILE.FileDateTime: 1017666176
FILE.FileSize: 1240
FILE.FileType: 2
FILE.SectionsFound: ANY_TAG, IFD0, THUMBNAIL, COMMENT
COMPUTED.html: width="1" height="1"
COMPUTED.Height: 1
COMPUTED.Width: 1
COMPUTED.IsColor: 1
COMPUTED.ByteOrderMotorola: 1
COMPUTED.UserComment: Exif test image.
COMPUTED.UserCommentEncoding: ASCII
COMPUTED.Copyright: Photo (c) M.Boerger, Edited by M.Boerger.
COMPUTED.Copyright.Photographer: Photo (c) M.Boerger
COMPUTED.Copyright.Editor: Edited by M.Boerger.
IFD0.Copyright: Photo (c) M.Boerger
IFD0.UserComment: ASCII
THUMBNAIL.JPEGInterchangeFormat: 134
THUMBNAIL.JPEGInterchangeFormatLength: 523
COMMENT.0: Comment #1.
COMMENT.1: Comment #2.
COMMENT.2: Comment #3end
THUMBNAIL.JPEGInterchangeFormat: 134
THUMBNAIL.Thumbnail.Height: 1
THUMBNAIL.Thumbnail.Height: 1

source http://php.net/manual/en/function.exif-read-data.php