3D visualization of astronomy data using immersive displays

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1 ithes coffee meeting Riken D visualization of astronomy data using immersive displays Gilles Ferrand Research Scientist Astrophysical Big Bang Laboratory

01 A collaboration Astronomy Computer Science A short-term pilot

Interdisciplinary/New Directions Research Collaboration Initiation

English Physics and Astronomy radio astronomer Gilles Ferrand

2 01 A collaboration Astronomy Computer Science A short-term pilot project, funded locally by: Faculty of Science: Interdisciplinary/New Directions Research Collaboration Initiation Grants University Collaborative Research Program (UCRP) Jayanne English Physics and Astronomy radio astronomer Gilles Ferrand Physics and Astronomy numericist Pourang Irani Computer Science Human-Computer Interaction Lab

3 02 The structure and evolution of supernova remnants simulations Grex supercomputer, UofM, 2011 observations Chandra observatory, NASA, 1999

03 Our testbed galaxy: NGC 3198 r.a. = 10h 19m 54.

4 03 Our testbed galaxy: NGC 3198 r.a. = 10h 19m 54.99s dec. = (constellation: Ursa Major) redshift = distance = 31 Mly = 9.5 Mpc type: SB(rs)c infrared (Spitzer) near IR/optical (SDSS) ultraviolet (GALEX)

5 04 Radio data cubes of galaxies We can probe galactic motion using Doppler shift of the HI 21 cm spectral line mean velocity field channel maps wavelength/frequency is a proxy for the radial velocity of the emitter (illustrations from a presentation by David S. Meier) The resulting 3D data cube has 2 spatial dimensions and 1 velocity dimension

6 05 A typical radio-astronomer desktop (Karma) NGC 3198 HI moment 0 data from the THINGS survey

7 06 What do we mean by 3D visualization? The world as represented in the visual arts tradition The world as we actually perceive it 2D flat 3D stereo 3D virtual reality slices/ projections perspective and shading stereoscopy (fixed viewpoint) stereoscopy + motion parallax on any personal computer on advanced displays: dual projectors, tracking cameras

8 07 3D displays for Virtual Reality fish tanks headsets the Rift by Oculus (Facebook) a CAVE by Visbox the zspace tabletop the Vive by HTC / Valve

9 08 Virtual Reality with the Unity engine display devices navigation/interaction devices CAVE display stereo glasses tracking IR cameras Flystick wand specialized software provided with the hardware middleware for interfacing with VR systems 3D models of objects, with textures camera(s) lightning a popular cross-platform visual development environment for 3D (gaming) applications C# scripts defining behaviours of objects

10 09 Loading the astronomical data raw values astropy.io.fits standard for data storage: FITS = Flexible Image Transport System - header - (stacks of) images/tables = arrays of numbers loaded as a 3D texture = look-up table property of a shader that is assigned to a material that is attached to an object = object painter

10 Volume rendering of a 3D data cube The data cube loaded as a 3D texture (= look-up table) assigned to a material attached to an object (a simple cube) The data

11 10 Volume rendering of a 3D data cube The data cube loaded as a 3D texture (= look-up table) assigned to a material attached to an object (a simple cube) The data cube is stepped through along each line-of-sight: at each step the data is sampled, interpreted as a colour, and accumulated This is done on the GPU, using custom shaders

12 11 Visitors on Campus: in the CAVE, on the zspace First feedback positive. You have to see it for yourself! No image or even video can convey the experience...

13 12 Testing the HTC Vive great immersion at a very affordable price!

13 Perspectives: Colour transfer functions The colour transfer function defines the colour of any data point (a voxel in 3D) as a function of parameters such as intensity, velocity, coordinates.

14 13 Perspectives: Colour transfer functions The colour transfer function defines the colour of any data point (a voxel in 3D) as a function of parameters such as intensity, velocity, coordinates. Colour can be given in machine space vs. perceptual space Common examples: - Use grayscale to show emission intensity - Use blue-red to show blueshift/redshift Jayanne English uses visual art techniques to clarify/support information

14 Perspectives: Natural interaction with a data cube Example: Use 3D cursor for selection - display coordinates and data value - select all data of the same value (iso-contouring) - show where a

15 14 Perspectives: Natural interaction with a data cube Example: Use 3D cursor for selection - display coordinates and data value - select all data of the same value (iso-contouring) - show where a voxel falls on the histogram Example: Overlay other data - 2D on 3D: step an optical image through the cube, segment it and attach it to the cube s matching features - 3D on 3D: merge data cubes (as when making 2D image composites) Pourang Irani s HCI lab is devising new ways of interacting with data

16 15 Conclusion Aims of this exploratory project: Get a workbench that allows us to experiment with the aspects that we feel are important for our data (e.g. proper colouring, and overlaying other data) Raise general awareness in the astro community, and build a special interest group We welcome questions/comments, and new collaborators We are on the lookout for - funding sources and non-academic partners - people with the relevant interdisciplinary skills

TRANSFORMATIONAL TECHNOLOGIES

TRANSFORMATIONAL TECHNOLOGIES FOR THREE-DIMENSIONAL VISUALISATION (AND ANALYSIS) Christopher Fluke ESO 3D2014 CRICOS provider 00111D Thank you Key Collaborators: David Barnes Monash University e-research