PixInsight Forum (historical)
PixInsight => Announcements => Topic started by: Pleiades on 2006 June 16 04:59:23
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The latest version of the PixInsight Standard core application, 1.0.1.207 Beta 1, is now available for download:
http://pleiades-astrophoto.com/download/STD/index.html
Along with a number of bug fixes and important optimizations, this new version introduces the new PixelMath process.
This release is entirely based on our customized version of Qt 4.1.3 and PCL 1.0.1.70 RC3.
New PixelMath process
This process can be accessed from the Process Explorer, and also through Process > PixelMath > PixelMath from the main menu.
This process is a complete rewrite and redesign from scratch; it is very different from its counterpart in the LE version.
A brief tutorial describing PixelMath and its syntax, including all operators, functions and a number of practical examples, is available here:
http://www.pleiades-astrophoto.com/tutorials/STD/PixelMath/
These are the main characteristics of the new PixelMath, excerpted from the above document:
An advanced, proprietary expression parser/interpreter is used to decode and execute arbitrary mathematical expressions that can be applied to any number of images. PixelMath expressions are written and edited as plain text. Common algebraic notation is used, following a set of syntax rules that form a superset of the C syntax, with extensions and some new operators adapted to manage 2-D images efficiently.
Three different expressions can be defined and applied, one for each individual RGB channel, or a single expression can be used for all nominal channels of the target image (default setting). This is a user-selectable option.
Optional automatic rescaling of the result to an arbitrary output range.
More than 30 functions available, including statistical, algebraic and transcendental functions.
Optional usage of a 64-bit floating point temporary image to accumulate intermediate results. By default, a 32-bit floating point temporary image is used.
Optimized detection and precalculation of expression invariants. For example, in the expression Min(img)*x, the function call Min(img) is evaluated as an invariant, equal to the minimum sample value of the image img (see Section 3 below). Invariants are precalculated prior expression execution.
Operand images can have arbitrary dimensions and/or color spaces. If images with different sizes are involved in a PixelMath execution, interpolation is carried out on the fly as appropriate to generate the required pixel values. If different color spaces are involved (e.g. RGB and grayscale), the process manages grayscale images are RGB images with equal sample values for all nominal RGB channels automatically.
Optional generation of a new image with the result of the PixelMath calculation. For newly generated images, a complete set of parameters can be specified: dimensions, color space, sample format and image identifier. Optionally, newly generated images can adopt the same properties of the target image.
Maskable process. PixelMath can be applied through masks.
Previewable process. PixelMath can be tried out on previews, even if generation of a new image has been selected.
Advanced expression editor interface with pre-evaluation of expressions for syntax check and diagnostics of potential errors.
Possibility of executing PixelMath instances in the global context (to generate new images), along with normal execution on a target view.
Enjoy it!
The Pleiades Development Team