[sane-devel] Exif informations

Till Kamppeter till.kamppeter@gmx.net
Sun, 18 May 2003 17:02:22 +0200

Is the device which you are using really a scanner?

If it is a locally (USB, SCSI, parallel, ISA or PCI card) scanner and 
the Windows driver gives you the possibility to save the scanned image 
as a JPEG with EXIF info, the EXIF info is most probably generated by 
the Windows driver, as local scanners usually send raw image data over 
the wire. In this case it would be an idea of enhancement for SANE or 
its frontends to save info about the image and or applied correction 
operations in an EXIF header when saving the image as JPEG.

If it is a network-connected high-end multi-function device (usually 
based on an office copy machine) which allows the user to download scans 
as JPEG files via a web interface, FTP, or e-mail you can apply 
libexif-based tools on the JPEG files as soon as they are onm your hard 
disk, see below about these tools.

If your device is a digital camera (or the small HP PhotoSmart scanner 
which scans onto a photo memory card) the camera´s firmware stores the 
camera settings in an EXIF haeder when you let the camera save the photo 
as JPEG on the memory card. Use gtkam (gphoto2 frontend with remote 
control feature, http://www.gphoto.org/) or the buttons of the camera to 
take the photos, then they get saved on the card. If there is a driver 
for SANE to take or download photos (does this exist?) it is possible 
that you get the image as raw data, without EXIF header (as from a local 
scanner). Download the photos via USB mass storage or gphoto2. Then use 
libexif-base tools for reading and editing the EXIF headers.

libexif and the "exif" (command line) and "gexif" (graphical) frontends 
you can find in many distros or on 
http://sourceforge.net/projects/libexif. In addition, gtkam, gphoto2, 
flphoto (http://www.easysw.com/~mike/flphoto/), and several web album 
systems support EXIF (when compiled with libexif).


Georges Roux wrote:
> Yes like this:
> EXIF tags in 'IMG002.jpg' ('Intel' byte order):
> --------------------+----------------------------------------------------------
> Tag                 
> |Value                                                    
> --------------------+----------------------------------------------------------
> Manufacturer        
> |Nikon                                                    
> x-Resolution        
> |2900/1                                                   
> y-Resolution        
> |2900/1                                                   
> Resolution Unit     
> |Inch                                                     
> Date and Time       |2003.05.17 
> 22.38.02                                      
> YCbCr Positioning   
> |centered                                                 
> Exif Version        |Exif Version 
> 2.1                                         
> ComponentsConfigurat|Y Cb Cr 
> -                                                
> Maker Note          |32 bytes unknown 
> data                                    
> FlashPixVersion     |FlashPix Version 
> 1.0                                     
> Color Space         
> |sRGB                                                     
> PixelXDimension     
> |3979                                                     
> PixelYDimension     
> |2674                                                     
> --------------------+----------------------------------------------------------
> to have some informations about parameters, date...
> Georges
> Henning Meier-Geinitz wrote:
>>On Sat, May 17, 2003 at 05:44:25PM +0200, Georges Roux wrote:
>>>Is it possible to have Exif, supported in a next release?
>>Can you give some more details? Do you want the frontends to output
>>the images as exif? For XSane?