Archive for the ‘Color’ Category

Waveform monitor

Saturday, July 3rd, 2010

waveformOld analog video requires white balance and color calibration with a specialized oscilloscope known as the waveform monitor.  Chuck Preston and I thought it would be fun to create this “retro”.  Ideally, we would like to add the knobs for adjusting color, white balance as other feature.  Maybe some day….

Adjust HSV

Sunday, November 29th, 2009

HSVThought I would try applying HSV in pixelbender as well.  The  algorithm I am using maybe referenced from University of Haifa, Israel.  Please consider my Flex app. demo and pixelbender source (pbk).

Adjust CIE L*a*b*

Friday, November 27th, 2009

labColorThought I exercise on a pixelbender filter for adjusting brightness (L*), red<->green(a*), and yellow<->blue(b*) in CIE L*a*b* color space.  I am generalizing the sRGB to Tristimulus (XYZ) formulation and assuming D50 light source.

PixelBender source (pbk)Flex App. demo

Reference(s):

1) Principles of Color Technology, 2nd edition by Billmeyer & Saltzman.

2) http://en.wikipedia.org/wiki/SRGB

3×3 Matrix transform

Monday, November 16th, 2009

A few months ago a friend from FlashMN asked about finding a coordinate transform from one volume (3D space) to another.  Well, here is one of the simplest method, solving for a 3×3 matrix (assuming linear, non-distorted transform on a plane).  This is written in Mathematica 7 notebook.  Reference: Measuring Color 2nd Edition by R. W. Hunt, pg. 204-5.

VolumeHistogram

Sunday, October 11th, 2009

VolHistColor pixel coordinates are three dimensional and therefore best visualized and manipulated in a volume.  The first time I experienced this was through a statistic analysis tool, JMP (SAS software) in my color theory class at Rochester Institute of Technology (RIT).  Later, I have used similar color visualization and manipulation tools as ColorBlind and Candela by Bruce Lindbloom.

This volume histogram was first written in C# and later migrated to Flex. Added this evening was onEnterFrame() for the rotation control so as to have “spin” animation.  This tool was developed for visualization and count only.  Hope to have manipulation capability in the next version.

Download Flex and C# demo source from GoogleCode.

Learn more about the C# demo here.

Adjust Tone-Reproduction

Saturday, August 1st, 2009

One of the most effective feature in an image editing application is the level or histogram tool.  Essentially, the feature allows user to manipulate the tone reproduction.  Another variation of this is the curve adjustment or cummulative histogram tool.  I have combined both views into a single tool.  The user interface follows the standard photoshop layout and the Flex Color picker open/close transition for access.  Might you try it out below or download the source from Google Code?

Screen Shot 2012-06-10 at 5.23.09 PM