Although VB had it’s limitations, it was damn easy to filter an input string for a numerical value.

Here is how to do it in C#. You’ll need to use System.Text.RegularExpressions in the header

private static int VBVal(string sInput)
{
        string sOutput = string.Empty;
        MatchCollection oMatches = Regex.Matches(sInput, "\\d+");
        foreach (Match oMatch in oMatches)
        {
                sOutput += oMatch.ToString();
        }
        return (int)sOutput;
}

When attempting to get machines to process images you sometimes run into noise problems. Filters are regularly applied first to clean them up.

Editing the contrast of an image changes its dynamic range. In its most basic form, it will move pixel values away from the center (normally 128 if using 8 bits per color).

There are many different ways to to perform contrast adjustment.
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I’m in the process of writing some code to detect the stars in astromical images. One of the filters I need to apply to an image is to convert it to greyscale.

Conversion to greyscale is relatively straightforward – The red, green and blue values of a pixel all need to be set to the same value.

There is one caveat, and that is that our eyes are sensitive to different colors. This means that color images tend to have lots of blue and red when compared to green.
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This post is part of a series on understanding the meaning behind the values contained in a Two Line Element set, or Keplerian Elements. The main article is here.

Calculation of the Julian Day Number (JDN)

Julian day numbers are regularly used in astronomy instead of a date.

Julian day numbers are simply the count of days that have elapse since noon on January 1, 4713 BC Greenwich time using the Julian proleptic calendar.
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I recently needed to find the shortest distance between any two line segments in 3D space.

I managed to find some C++ code online at http://softsurfer.com/Archive/algorithm_0106/algorithm_0106.htm which I converted to C#.

It’s fairly easy to use. If you only need it for 2D space, just set the Z values to 0.

Please post a comment if you find this useful.
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