use image metadata to determine crop-factor and hfov

[Christoph Anton Mitterer]

Hi.

Currently when I open some images in hugin, it only detects the focal length (by using metadata information).
It would be nice if the same could be done, too, for the crop factor and the HVOF.

I'm not sure whether these are standardised Exif-Tags or not, but some camera manufacturers (at least) encode this in their "binary" fields.

If I take e.g. images made by my Olympus E-5 or the E-510 and do a:
exiv2 -pt image.orf
I don't find any tag which I'd say it's the crop factor or the HFOV.

However:
exiftool seems to be very well able to get these information, e.g.:
$ exiftool P3096244.ORF | grep "^Scale Factor"
Scale Factor To 35 mm Equivalent: 2.0

$ exiftool P3096244.ORF | grep "^Field"
Field Of View : 65.1 deg (3.51 m)

Actually it seems to be able to get even more data out of Olympus' binary fields, you should have a look at them some might be perhaps of use for hugin?!

It's (especially for "end-users") a pain to decide their lense type (rectified, etc.),.. this would AFAIU make this not longer needed.
And the values are probably more correct (at least they differ from what hugin caculates if I enter just the crop factor and focal length).

I'd suppose that the other major manufacturers have similar fields encoded.

Cheers,
Chris.

[tmodes (tmodes)]

Hugin is already using the metadata to read crop factor and hfov. There is also some Olympus specific code. But this seems not to work for your camera. Can you provide a link to an example file so we can check.

[Christoph Anton Mitterer (calestyo)]

I've tried it now with several models (using images from the web):

E-1: works
E-3: doesn't work, sample image can be found e.g. here: http://asia.olympus-imaging.com/products/dslr/e3/sample/images/sample_01.jpg
E-5: doesn't work, sample image can be found e.g. here: http://asia.olympus-imaging.com/products/dslr/e5/sample/images/e5_sample_01.jpg
E-30: doesn't work, sample image can be found e.g. here: http://asia.olympus-imaging.com/products/dslr/e30/sample/images/sample_01.jpg
E-510: doesn't work, sample image can be found e.g. here: http://asia.olympus-imaging.com/products/dslr/e510/sample/images/sample_01.jpg
E-620: doesn't work, sample image can be found e.g. here: http://asia.olympus-imaging.com/products/dslr/e620/sample/images/sample_01.jpg

I guess at some point they've changed something in their meta-info and
all later cameras don't work (probably also the other E-3xx, E-4xx,
E5xx).

Cheers,
Chris.

[tmodes (tmodes)]

Fixed in repository. Will be included in 2011.0 beta 3.

[Christoph Anton Mitterer (calestyo)]

thx =)