IIPImage has been adopted by a number of users in the astronomy community due to it’s ability to handle both very large images and scientific-grade quantitative data. See, for example, this post from the Wide Field Astronomy Unit about putting online a massive image of our galaxy containing 1 billion stars. Although the image in that example is very large (the TIFF is over 150GB in size), the original scientific data has been reduced to 8 bits per channel for visualization purposes.
However, much astronomy data (and indeed scientific data in general), is in quantitative linear floating point format, requiring 32 bits per channel. Having access to such quantitative image data at this level of precision and dynamic range is important for carrying out scientific data analysis. And there are major benefits from having remote access to very large floating point data in a number of tasks in astronomy, astrophysics and planetary science.
New Server Features
IIPImage already handled 8 and 16 bit per channel data and full 32 bit support for both integer and floating point has now been added in association with the Institute of Astrophysics and the Geosciences Laboratory of the University of Paris Sud. Much of the core image processing within iipsrv is now carried out using 32 bits of dynamic range, enabling real-time access to and the real-time processing of extremely large scientific data sets.
The speed and scalability of the IIPImage server is one of its most important features. The use and processing of floating point data is far more memory and computationally expensive than for standard 8 bit data and could have had an impact on server performance. iipsrv has, therefore, been heavily optimized to minimize this, which has also significantly improved speeds for all types of image. Improvements have also been made to iipsrv’s handling of extremely large images and it is now able to comfortably and efficiently handle terabyte size images of any bit depth.
In addition, a number of other important new features have been added to the IIPImage server, that although aimed at astronomy applications, are useful in a wide range of disciplines:
- Gamma correction (GAM parameter)
- Minimum and maximum cuts (MINMAX parameter)
- Full resolution data profiles (PFL parameter)
- Dynamic color-mapping (CMP parameter)
These features are available in the latest server code on GitHub and will form part of the forthcoming 1.0 server release. For more details on the syntax for the new parameters, see the IIP protocol documentation.
In terms of file formats for floating point data, TIFF is not only able to store 8 bits per channel images, but also 16 bit and both 32 bit integer and 32 bit floating point data, meaning that all the standard TIFF imaging software pipeline can continue to be used with IIPImage. See the image documentation for more details on image formats and the software STIFF for generating TIFF files suitable for IIPImage from FITS data.