Friday, June 26, 2009

Are Febreze Plug Ins A Fire Hazard



Before that came to light version 1.5 of Core PixInsight , the color calibration carried out through ChannelMatch . For this, after generating the linear RGB image, estimated the overall statistics of the image from a preview of the sky. The point was to match the median values \u200b\u200bby changing the linear correction factors ChannelMatch. But why the median? Simply because we take it as a reference on a preview that dominate the background pixels, this value is a good estimate of the main peak of distribution of own sky.

As can be seen in the video, the color calibration is performed when image data are linear, which is very useful help of a transfer function display ( ScreenTransferFunction ). ;


Currently there is a tool which automatically cut the same, but with a few clicks. PixInsight Core is available in 1.5 from a few days ago with the name of ColorCalibration .
ColorCalibration The idea is based on using as reference two types of sub images (or previews). First, the white reference and second reference sky.


The reference targets can be for example the total light emitted by a galaxy, since we can safely say that most of all light sources emitting in the continuum (mainly stars). And then a sky background reference (background), here always assumed to be neutral.


In the picture outlined in the video blog is more difficult to find a white reference, because it is an object of a different nature. Ie not emit the photographed object in the continuous spectrum, but it does so in more specific wavelengths (emission lines). For this reason, the user interacts with the global statistics of the sky background, instead of using a white reference when calibrating the overall color of the image.

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