Describing Pretty Pictures

If you've ever wanted to find images of Venus you might have used a search engine such as Google. The results can be variable and can often throw up the planet, the goddess, the Venus di Milo and even models of mobile phone. The trouble is that search engines are trying their best to work out what an image is from the surrounding text on the webpage but that doesn't always help distinguish different things with the same name. We really need a way to say that a particular image is of the planet Venus and not a brand of lady's razor. For this we need metadata; some extra data describing what the main data are.

The basic idea is to label your data - images, videos, audio or even text - in a standard way so that computers can have a good idea as to what it is. In professional astronomy this has been done for years using the Flexible Image Transport System (FITS) for image data. FITS files can contain all sorts of information including the object, the coordinates, the observing wavelength and much, much more. Having that information with the image can be a life saver if you lose your log book or forget what an image is of. The downside of FITS is that it has never really taken off outside the professional astronomical community despite projects such as FITS Liberator from ESA/Hubble. Trying to get everyone to adopt FITS when JPEG, BMP, GIF, PNG are so widespread really isn't going to happen. So, what do you do? You try to adapt the common file formats we have already to include the metadata.

One of the key projects for the International Year of Astronomy is the Virtual Astronomy Multimedia Project (VAMP). Their aim is to get creators of pretty pictures - astronomical imagery used foreducation and public outreach (EPO) - to tag them with as much information as is relevant. The aim is to allow the creation of easily searchable databases of astronomical imagery for a range of potential applications. The VAMP project will use methods similar to the way digital cameras already tag images with basic information such as the camera model. The project has been working since last year and the final candidate document for the VAMP standard (AVM) has been out for a few months. They even have a prototype online tagging tool, which will generate an XML file which can be attached to your image in Photoshop or Adobe Bridge, so they are in good shape.

While I think the VAMP project still has some more work to do, these efforts will soon make it easy for everyone to tag their astronomical pictures. I look forward to the day I can use Google to search the web for beautiful images by right ascension/declination, observing wavelength or even by type of astronomical object.

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Posted in astro blog by Stuart on Tuesday 26th Aug 2008 (20:44 BST) | Permalink
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