Resample pixels for display
At this point, we have the grid of points you selected overlaying the grid of the image survey. From here, we resample the image survey to get the values of your grid. This is done is one of three ways.
- Nearest Neighbor
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By taking the center of each pixel in your
grid, SkyView looks for the nearest pixel center in the image
survey grid and uses that value in your grid.
- Interpolation
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Instead of just taking the closest image survey
grid value, this time all the surrounding survey grid values are
average together to obtain the value of a single pixel in your grid.
- Clip resampling
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Here the output pixels are overlaid on the input pixels and act
as a window clipping the inputs. The output pixel value is the
average over the clip window.
- Lanczos and Spline resampling
- These higher order methods tend to do the best job of resampling well-sampled images. They calculate the value at a point using not just the adjacent pixels, but kernel or nearby pixel values.
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SkyView has been developed with generous support from the NASA AISR and ADP programs (P.I. Thomas A. McGlynn) under the auspices of the High Energy Astrophysics Science Archive Research Center (HEASARC) at the NASA/ GSFC Astrophysics Science Division.
We gratefully acknowledge the support of NASA and contributors of SkyView surveys.
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