Re: importing image and getting numbers from the gray intensity

*To*: mathgroup at smc.vnet.net*Subject*: [mg49371] Re: importing image and getting numbers from the gray intensity*From*: Paul Abbott <paul at physics.uwa.edu.au>*Date*: Fri, 16 Jul 2004 06:07:05 -0400 (EDT)*Organization*: The University of Western Australia*References*: <cd5okp$b2c$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

In article <cd5okp$b2c$1 at smc.vnet.net>, sean_incali at yahoo.com (sean kim) wrote: > let's say you have an image of gray bands of varying intensity. > > such as the one seen on the website, > > http://encyclopedia.thefreedictionary.com/SDS-PAGE > > Is there anyway to change the picture or do something and be able to > get numerical values for those bands? > > maybe define a vertical line and then go to the center of the each > bands and measure how intense the gray is. > > or maybe define a rectangle and get the gray intensity in that... > > is there a packages or codes for doing that? NIH image program which > is freely avaialble can do this. But I wanted to do it in Mathematica. There are several ways to do this. One way is to copy the image, paste it into a Mathematica Notebook and then use Cell | Convert To | InputForm This will give you an input cell that includes a RasterArray of RGBColors. Call this cell pixels, say, and enter it. You can then access the pixels as follows: pixels = First[Cases[pixels, RasterArray[x__] :> x, Infinity]] /. RGBColor[r_, g_, b_] :> (r + g + b)/3 You can re-draw the picture as follows: ListDensityPlot[pixels, Mesh -> False]; and do any other manipulation you want on the pixels. Cheers, Paul -- Paul Abbott Phone: +61 8 9380 2734 School of Physics, M013 Fax: +61 8 9380 1014 The University of Western Australia (CRICOS Provider No 00126G) 35 Stirling Highway Crawley WA 6009 mailto:paul at physics.uwa.edu.au AUSTRALIA http://physics.uwa.edu.au/~paul