Pixel summary data?

[Matlack, Glenn]

Dear ImageJ Community,

I am trying to use ImageJ to describe surface texture, which can be reduced to a distribution of pixel values.  Is there a function summarizing the pixel distribution within an area of interest?  For example, if all the pixels are either black or white (i.e. pixel values are binary), can I query ImageJ to discover a) how many pixels are in the area of interest and b) how many are black?  I greatly appreciate any thoughts/comments/suggestions!

Many thanks,
Glenn Matlack

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[Herbie-4]

Good day Glenn,

what about looking at the histogram of the ROI?

Best

::::::::::::::::::::::::::::::::::::::::
On 03.02.15 17:14, Matlack, Glenn wrote:

> Dear ImageJ Community,
>
> I am trying to use ImageJ to describe surface texture, which can be
> reduced to a distribution of pixel values.  Is there a function
> summarizing the pixel distribution within an area of interest?  For
> example, if all the pixels are either black or white (i.e. pixel
> values are binary), can I query ImageJ to discover a) how many pixels
> are in the area of interest and b) how many are black?  I greatly
> appreciate any thoughts/comments/suggestions!
>
> Many thanks, Glenn Matlack
>
> -- ImageJ mailing list: http://imagej.nih.gov/ij/list.html
>

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[mattjackson]

Here's a macro to count up dark (=0) and white (=255) pixels in a rectangular selection:

getSelectionBounds(x,y,width,height);
yend = y+height;
xend = x+width;
WhiteCount=0;
DarkCount=0;

for(j=y;j<yend;j++){
        for(i=x;i<xend;i++){
                I = getPixel(i,j);
                if(I == 0){
                        DarkCount=DarkCount+1;
                }else{
                        WhiteCount=WhiteCount+1;
                }
        }
}

print("Dark White");
print(d2s(DarkCount,0)+" "+d2s(WhiteCount,0));

[Cammer, Michael]

Also...

// Assumes images are 8 bit; no error checking for this.
function methodByHistogram() {
  getHistogram(values, counts, 256);
  print("Black \t White");
  print(counts[0]+" \t "+counts[255]);
}

=========================================================================
 Michael Cammer, Microscopy Core & Skirball Institute, NYU Langone Medical Center
                          Cell:  914-309-3270     Temporary location:  SK2-7
          http://ocs.med.nyu.edu/microscopy & http://microscopynotes.com/


-----Original Message-----
From: ImageJ Interest Group [mailto:[hidden email]] On Behalf Of mattjackson
Sent: Tuesday, February 03, 2015 12:23 PM
To: [hidden email]
Subject: Re: Pixel summary data?

Here's a macro to count up dark (=0) and white (=255) pixels in a rectangular
selection:

getSelectionBounds(x,y,width,height);
yend = y+height;
xend = x+width;
WhiteCount=0;
DarkCount=0;

for(j=y;j<yend;j++){
        for(i=x;i<xend;i++){
                I = getPixel(i,j);
                if(I == 0){
                        DarkCount=DarkCount+1;
                }else{
                        WhiteCount=WhiteCount+1;
                }
        }
}

print("Dark White");
print(d2s(DarkCount,0)+" "+d2s(WhiteCount,0));



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[mattjackson]

Good call, Michael. I learned to program in Fortran 77, so I tend to program strings like that instead of looking for built in functions. Still trying to break that habit.

[Matlack, Glenn]

Matthew and Michael,

Many thanks - that looks very helpful!

Best,
Glenn

-----Original Message-----
From: ImageJ Interest Group [mailto:[hidden email]] On Behalf Of mattjackson
Sent: Tuesday, February 03, 2015 1:20 PM
To: [hidden email]
Subject: Re: Pixel summary data?

Good call, Michael. I learned to program in Fortran 77, so I tend to program strings like that instead of looking for built in functions. Still trying to break that habit.



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