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February 28, 08

Removing "sensitive" meta data using ExifTool

As Ipernity extracts Exif meta data to a great extent, i. e. not only "basic" information such as exposure, aperture, creation dates, etc., but really almost "all that's there" and I am usually very privacy-aware and "data-economical", that is an aspect I have been sort of uncomfortable with.
Especially data such as the Serial Number of the camera and other "sensitive" meta data that could easily be used to trace back to an individual - and are of hardly any use for other purposes such as figuring out the method of shooting - caught my attention.

[On a sidenote to kind of fend off speculations of paranoia on my part: last year Canon announced it would be potentially possible to track down the person who had photographed/-copied the latest Harry Potter novel by means of the meta data of the camera used, cf. Times Online]

Of course you can disable displaying Exif data but I do want to let others interested in exposure or ISO easily have access to this information. So disabling display of Exif all together is no option for me.
The only solution thus is to remove all IMO "unnecessary" meta data from the files before uploading them.

Here is what I have figured out for myself so far, I might overhaul it in the future since it is rather rudimentary - but sufficient - at the moment.

I decided to use ExifTool, which is
a platform-independent Perl library plus a command-line application for reading, writing and editing meta information in image, audio and video files.

It is a very powerful and flexible tool that can do a lot more than what I use it for - e. g. also handle meta data from other file types than images.

At the moment I have decided to do the following with it:

  1. exiftool -all= *.jpg
    This removes all meta data from all files ending with the extension .jpg in the current folder, moving the originals to files with the additional extension "_original".
  2. exiftool -overwrite_original -tagsfromfile *_original -make -model -exposuretime -aperturevalue -flash -iso -lens -focallength -orientation -datetimeoriginal *.jpg

    This copies the specified meta data (Make, Model, Exposure, etc.) from the "backuped" _original files to those stripped clean of any data.

Of course the fields can be extended or reduced to everyone's personal needs and the whole thing put into a nice shell script etc.

I still need to figure out what information is stored by my camera in what fields and what groups - it's well documented but rather complex - so I can specify more precisely what data to copy.

As I wrote above, this solution is rather rudimentary and not perfected, since e. g. certain fields (e. g. Components Configuration: YCbCr) are created - I assume because of interdependence with other fields/groups and meta data specifications -, but functional for the moment and a better solution for me to either shutting off the display of Exif data completely or showing everything.

Published at 13:08 / 3 comments / 456 visits
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February 28, 08

Ipernity Feature Ramblings - "view as slideshow" for other "image collections" than albums

= Background =
One of the really nice features on Ipernity is the "view as slideshow" option for albums, which you can even watch in an animated fashion and/or with a "music carpet" (what is the proper English word for "Musikteppich" anyway?).

I won't dig into questions about extending this functionality [I'll do that in a seperate post:)] with things such as full screen display etc., but rather discuss "porting" the slideshow feature to other forms of image collections than the "classical" album.

= As-Is State =
Currently to create a slideshow - other than showing all docs -, you have to create an album and assign certain images to be part of it.
This has the benefit that you can also define the order of the images in the album/slideshow to e. g. create suspense.

= Suggestion =
Now what I think would be a nice extension of the whole slideshow concept would be if not only albums could be displayed in this fashion but also other forms of image compilations, i. e. via tags.

Selecting a tag right now displays all documents in the current user's profile relating to it as thumbnails or in a detailed view.
From here you can also go and "Explore this tag" to see all docs&posts Ipernity-wide in relation to this tag.

I suggest adding another option "view as slideshow" that would generate a slideshow displaying the tag-filtered images.

This way one could get an overview of "content-related" pictures that do not share the same album, which I think could be very interesting.

= Implementation =
I assume it should be fairly easy to implement (although I have no knowledge of the backend code, so I might be totally wrong).

The URL for an album-slideshow is:
www.ipernity.com/doc/$member/slideshow/album/$album_id

The URL for a sort by tag is:
www.ipernity.com/tag/$member/keyword/$tag_id
www.ipernity.com/tag/$member/profile/$tag_id

There seem to be two subcategories here to differentiate between "regular" and member tags.

So the URL for my suggestion would look something like this:
www.ipernity.com/tag/$member/slideshow/keyword|profile/$tag_id

Here tag instead of doc clarifies we are dealing with a tag-sort, whereas keyword or profile limit it down to "regular" or member tag kind. The $tag_id finally defines the concrete tag analogous to the $album_id.

Extrapolating from the URLs I assume database queries as well as the code should not be too laborious to adjust.
[Again, I am mostly guessing here, so please don't hate me for my ponderings, Ipernity coder(s)!]

= Possible issues =
As it is - to my taste far too - often the case people might feel they are losing "control" over what is done with their works. After all they have not defined such a filter to create a slideshow - other than when creating an album.
I do not think this should be an issue at all since people do provide the possibility of filtering their works when tagging images. If they are then displayed as thumbnails/details or in a slideshow manner - to me - does not make a great difference.

On the other hand it will allow greater flexibility and new forms of exploring collections of images.

 


In the "Unofficial ipernity Ideas and Wish Group" Roberto Ballerini in October 2007 posted a short entry titled "[GROUPS] Different viewing mechanisms" in which he askes for the possibility to

view a slideshow of a group pool or to look at the pool shots in a bigger size than thumbnails

This is kind of the same idea I tried to explain in this post but with focus on the sorting criterion "belongs to group".

Published at 14:32 / 5 comments / 360 visits
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( 2 posts )