Another Word For It Patrick Durusau on Topic Maps and Semantic Diversity

July 19, 2016

Proofing Images Tool – GAIA

As I was writing on Alex Duner’s JuxtaposeJS, which creates a slider over two images of the same scene (think before/after), I thought of another tool for comparing photos, a blink comparator.

Blink comparators were invented to make searching photographs of sky images, taken on different nights, for novas, variable stars or planets/asteroids, more efficient. The comparator would show first one image and then the other, rapidly, and any change in the image would stand out to the user. Asteroids would appear to “jump” from one location to another. Variable stars would shrink and swell. Novas would blink in and out.

Originally complex mechanical devices using glass plates, blink comparators are now found in astronomical image processing software, such as:
GAIA – Graphical Astronomy and Image Analysis Tool.

From the webpage:

GAIA is an highly interactive image display tool but with the additional capability of being extendable to integrate other programs and to manipulate and display data-cubes. At present image analysis extensions are provided that cover the astronomically interesting areas of aperture & optimal photometry, automatic source detection, surface photometry, contouring, arbitrary region analysis, celestial coordinate readout, calibration and modification, grid overlays, blink comparison, image defect patching, polarization vector plotting and the ability to connect to resources available in Virtual Observatory catalogues and image archives, as well as the older Skycat formats.

GAIA also features tools for interactively displaying image planes from data-cubes and plotting spectra extracted from the third dimension. It can also display 3D visualisations of data-cubes using iso-surfaces and volume rendering.

It’s capabilities include:

  • Image Display Capabilities
    • Display of images in FITS and Starlink NDF formats.
    • Panning, zooming, data range and colour table changes.
    • Continuous display of the cursor position and image data value.
    • Display of many images.
    • Annotation, using text and line graphics (boxes, circles, polygons, lines with arrowheads, ellipses…).
    • Printing.
    • Real time pixel value table.
    • Display of image planes from data cubes.
    • Display of point and region spectra extracted from cubes.
    • Display of images and catalogues from SAMP-aware applications.
    • Selection of 2D or 3D regions using an integer mask.
  • Image Analysis Capabilities
    • Aperture photometry.
    • Optimal photometry.
    • Automated object detection.
    • Extended surface photometry.
    • Image patching.
    • Arbitrary shaped region analysis.
    • Contouring.
    • Polarization vector plotting and manipulation.
    • Blink comparison of displayed images.
    • Interactive position marking.
    • Celestial co-ordinates readout.
    • Astrometric calibration.
    • Astrometric grid overlay.
    • Celestial co-ordinate system selection.
    • Sky co-ordinate offsets.
    • Real time profiling.
    • Object parameterization.
  • Catalogue Capabilities
    • VO capabilities
      • Cone search queries
      • Simple image access queries
    • Skycat capabilities
      • Plot positions in your field from a range of on-line catalogues (various, including HST guide stars).
      • Query databases about objects in field (NED and SIMBAD).
      • Display images of any region of sky (Digital Sky Survey).
      • Query archives of any observations available for a region of sky (HST, NTT and CFHT).
      • Display positions from local catalogues (allows selection and fine control over appearance of positions).
  • 3D Cube Handling
    • Display of image slices from NDF and FITS cubes.
    • Continuous extraction and display of spectra.
    • Collapsing, animation, detrending, filtering.
    • 3D visualisation with iso-surfaces and volume rendering.
    • Celestial, spectral and time coordinate handling.
  • CUPID catalogues and masks
    • Display catalogues in 2 or 3D
    • Display selected regions of masks in 2 or 3D

(highlighting added)

With a blink comparator, when offered an image you can quickly “proof” it against an earlier image of the same scene, looking for any enhancements or changes.

Moreover, if you have drone-based photo-reconnaissance images, a tool like GAIA will give you the capability to quickly compare them to other images.

I am hopeful you will also use this as an opportunity to explore the processing of astronomical images, which is an innocent enough explanation for powerful image processing software on your computer.

February 21, 2016

Photo-Reconnaissance For Your Revolution

Filed under: Crowd Sourcing,Government,Photo-Reconnaissance — Patrick Durusau @ 8:46 pm

Using Computer Vision to Analyze Aerial Big Data from UAVs During Disasters by Patrick Meier.

From the post:

Recent scientific research has shown that aerial imagery captured during a single 20-minute UAV flight can take more than half-a-day to analyze. We flew several dozen flights during the World Bank’s humanitarian UAV mission in response to Cyclone Pam earlier this year. The imagery we captured would’ve taken a single expert analyst a minimum 20 full-time workdays to make sense of. In other words, aerial imagery is already a Big Data problem. So my team and I are using human computing (crowdsourcing), machine computing (artificial intelligence) and computer vision to make sense of this new Big Data source.

Revolutionaries are chronically understaffed so Meier’s advice for natural disasters is equally applicable to disasters known as governments.

Imagine the Chicago police riot or Watts or the Rodney King riot where NGO leadership had real time data on government forces.

Meier’s book, Digital Humanitarians is a good advocacy book for the use of technology during “disasters.” It is written for non-specialists so you will have to look to other resources to build up your technical infrastructure.

PS: With the advent of cheap drones, imagine stitching together images from multiple drones with overlapping coverage. Could provide better real-time combat intelligence than more expensive options.

I first saw this in a tweet by Kirk Borne.

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