php detect image orientation "without exif"?

Question

my question is what to do to detect image orientation when exif data don't exist or don't have rotation value.

Example : photo from mobile phone

<?php echo exec('exiftool -Orientation file 2>&1'); 
// MOBILE -> returns -> Orientation : Rotate 90 CW
// DSLR -> returns -> empty ?>

When I try this

echo exif_read_data($multimedia_newPATH)['Orientation']
// Mobile Phone -> 6
// DSLR -> value 1 (horizontal and/or vertical) gives same 1

EDIT Many DSLR write orientation 1 (normal) for both when camera is horizon or vertical, so a normal php script would "think" there is no rotation to perform.

so is there a orientation algorithm or orientation recognition script ???? (face recognition exists, but is there orientation recognition ?)

*** note ; exiftool is in perl modules (Image::ExifTool) in WHM...

@odan yes jpg, Many DSLR write orientation 1 (normal) for both when cam horizon or vertical, so a normal php script would "think" there is no rotation to perform... — Jintor
– Jintor, Commented Jul 10, 2019 at 14:02
Sorry for going off topic, but might I ask what camera you are using that does this? I've never heard of a DSLR that didn't have a sensor to keep track of the orientation. Even old point and click cameras I've used have the ability to detect the orientation. — StarGeek
– StarGeek, Commented Jul 10, 2019 at 15:38
"recognition" of orientation is far easier than of faces: you just check the width against the height of the image. If width is larger, the it's landscape. Otherwise, it's portrait (unless they're equal, of course). — L. Scott Johnson
– L. Scott Johnson, Commented Jul 11, 2019 at 13:36
@l-scott-johnson the camera I tested (canon rebel 7D) does 6000x4000 in both cases horizontal AND vertical and orientation=1 in both cases as well, so how can the php script know if it's landscape ? — Jintor
– Jintor, Commented Jul 11, 2019 at 16:48

L. Scott Johnson · Accepted Answer · 2019-07-15 12:18:41Z

1

RotNet is a neural-network-based algorithm that does automatic image orientation and rotation.

Source: https://github.com/d4nst/RotNet

Description: https://d4nst.github.io/2017/01/12/image-orientation/

Google has also done some work on this problem, combining neural nets with using Captcha to crowd source the "difficult" cases.

answered Jul 15, 2019 at 12:18

L. Scott Johnson

4,4482 gold badges19 silver badges33 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

Jintor Over a year ago

Cool, thanks ;) the article looks good, I'll do some tests on it

Collectives™ on Stack Overflow

php detect image orientation "without exif"?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related