get 3 max and min values

[danibodor]

I know that you can get the max and min of a selection with the getMinAndMax function (or getStatistics). Is there a way to get e.g. the 3 maximum or minimum values. I was searching for a function to list all the values in a selection, and then sorting those and getting X maximal or minimal values. However, I cannot find a way of listing all the values in my selection. Also, I don't know if it possible to then easily sort them to get the highest values.

Can anyone help me?

Thanks!

[Gluender-2]

>I know that you can get the max and min of a selection with the
>getMinAndMax function (or getStatistics). Is there a way to get e.g.
>the 3 maximum or minimum values. I was searching for a function to
>list all the values in a selection, and then sorting those and
>getting X maximal or minimal values. However, I cannot find a way of
>listing all the values in my selection. Also, I don't know if it
>possible to then easily sort them to get the highest values.
>
>Can anyone help me?
>
>Thanks!
>--
>View this message in context:
>http://n2.nabble.com/get-3-max-and-min-values-tp2640330p2640330.html
>Sent from the ImageJ mailing list archive at Nabble.com.

With 8 bit images you may use
getHistogram(values, counts, nBins[, histMin, histMax])

HTH
--

                   Herbie

          ------------------------
          <http://www.gluender.de>

[danibodor]

yes, but this doesnt really work well for 16 bit images. and i don't want to compress the data to 8bit.

any other suggestions?

Gluender-2 wrote

>I know that you can get the max and min of a selection with the
>getMinAndMax function (or getStatistics). Is there a way to get e.g.
>the 3 maximum or minimum values. I was searching for a function to
>list all the values in a selection, and then sorting those and
>getting X maximal or minimal values. However, I cannot find a way of
>listing all the values in my selection. Also, I don't know if it
>possible to then easily sort them to get the highest values.
>
>Can anyone help me?
>
>Thanks!
>--
>View this message in context:
>http://n2.nabble.com/get-3-max-and-min-values-tp2640330p2640330.html
>Sent from the ImageJ mailing list archive at Nabble.com.

With 8 bit images you may use
getHistogram(values, counts, nBins[, histMin, histMax])

HTH
--

                   Herbie

          ------------------------
          <http://www.gluender.de>

[Michael Schmid]

Hi Dani,


There are two ways:

(1) Get the histogram and analyze it. For float images, the accuracy  
will be limited, however.

(2) The "destructive way", with higher accuracy for float images:

First make a copy of your image to work with.

Use getStatistics to get the maximum. Then use the new  
process>Math>Macro command to eliminate the pixel(s) with value=maximum:

run("Macro...", "  code=[if(v>="+myMax+") v="+minValue+";]");
where myMax is the maximum from the statistics (beware of rounding  
error in float numbers converted to a string, so set it to a slightly  
lower value).
minValue=0 for integer images, and -1.79E308 for float images.

Again, repeat for 2nd-highest values (now the previous maximum is not  
a highest value any more), etc.

Michael
________________________________________________________________

On 15 Apr 2009, at 19:48, danibodor wrote:

> I know that you can get the max and min of a selection with the  
> getMinAndMax function (or getStatistics). Is there a way to get  
> e.g. the 3 maximum or minimum values. I was searching for a  
> function to list all the values in a selection, and then sorting  
> those and getting X maximal or minimal values. However, I cannot  
> find a way of listing all the values in my selection. Also, I don't  
> know if it possible to then easily sort them to get the highest  
> values.
>
> Can anyone help me?
>
> Thanks!

[Christopher Coulon-2]

> I know that you can get the max and min of a selection with the getMinAndMax
> function (or getStatistics). Is there a way to get e.g. the 3 maximum or
> minimum values. I was searching for a function to list all the values in a
> selection, and then sorting those and getting X maximal or minimal values.
> However, I cannot find a way of listing all the values in my selection. Also,
> I don't know if it possible to then easily sort them to get the highest
> values.
>
I finally got a bit of time to write a demonstration macro to illustrate how
this can be done.  It is a bit crude, but it works.  :-)

Chris


run("HeLa Cells (1.3M, 48-bit RGB)");

w = getWidth;
h = getHeight;

maxPix1 = 0;
maxPix2 = 0;
maxPix3 = 0;

maxPix = 0;
minPix = 0;

minPix1 = 100000000.00;
minPix2 = 100000000.00;
minPix3 = 100000000.00;

for (slice = 1; slice <= 3; slice ++) {
    setSlice(slice);
    for (x = 0; x < w; x++) {
        for (y = 0; y < h; y++) {
            pix = getPixel(x, y);
            if (pix > maxPix1) {
                maxPix = maxPix1;
                maxPix1 = pix;
            }
            if (pix > maxPix2 && pix < maxPix1 || maxPix2 < maxPix && maxPix
< maxPix1) {
                if (pix > maxPix) {
                    if (pix < maxPix1) {
                        maxPix = maxPix2;
                        maxPix2 = pix;
                    }
                    else maxPix2 = maxPix;
                }
                else maxPix2 = maxPix;
            }
            if (pix > maxPix3 && pix < maxPix2 || maxPix3 < maxPix && maxPix
< maxPix2) {
                if (pix > maxPix) {
                    if (pix < maxPix2) {
                        maxPix = maxPix3;
                        maxPix3 = pix;
                    }
                    else maxPix3 = maxPix;
                }
                else maxPix3 = maxPix;
            }

            if (pix < minPix1) {
                minPix = minPix1;
                minPix1 = pix;
            }
            if (pix < minPix2 && pix > minPix1 || minPix2 > minPix && minPix
> minPix1) {
                if (pix < minPix) {
                    if (pix > minPix1) {
                        minPix2 = pix;
                    }
                    else minPix2 = minPix;
                }  
                else minPix2 = pix;
            }
            if (pix < minPix3 && pix > minPix2 || minPix3 > minPix && minPix
> minPix2) {
                if (pix < minPix) {
                    if (pix > minPix2) {
                        minPix = minPix3;
                        minPix3 = pix;
                    }
                    else minPix3 = minPix;
                }  
                else minPix3 = pix;
            }
        }
    }
}

print("max 1 = " + maxPix1 + " min 1 = " + minPix1);
print("max 2 = " + maxPix2 + " min 2 = " + minPix2);
print("max 3 = " + maxPix3 + " min 3 = " + minPix3);

       

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