Re: quick way to select the maximum pixel

Posted by Jacqueline Ross on Oct 07, 2009; 8:55pm
URL: http://imagej.273.s1.nabble.com/quick-way-to-select-the-maximum-pixel-tp3690812p3690814.html

Hi All,

I have a related question to the previous email about finding the
maximum grayscale pixels.

We recently discovered a couple of dead pixels in our monochrome camera.
They only show up when people have very very low intensity labelling and
are using long exposure times so normally not a problem.

However, it was suggested to me that to eliminate them from the images,
I could "find" the dead pixels (since they are maximum intensity) and
then fill them with the average grayscale value of the background (I
guess the minimum?).

Can anyone offer me some suggestions on how to do this?

Kind regards,

Jacqui

Jacqueline Ross

Biomedical Imaging Microscopist
Biomedical Imaging Research Unit
School of Medical Sciences
Faculty of Medical & Health Sciences
The University of Auckland
Private Bag 92019
Auckland, NEW ZEALAND

Tel: [phone] Ext 87438
Fax: [phone]

http://www.fmhs.auckland.ac.nz/sms/biru/


-----Original Message-----
From: ImageJ Interest Group [mailto:[hidden email]] On Behalf Of
Wayne Rasband
Sent: Thursday, 8 October 2009 5:20 a.m.
To: [hidden email]
Subject: Re: quick way to select the maximum pixel

 > does anyone know if there is a function to find the maximum
 > pixel in an image?

 > I know that i can get a measurement of the maximum pixel
 > and then run through the image pixel by pixel until i find
 > it, but i was hoping that there is a faster way to do this.

The Process>Binary>Find Maxima command seems to find the image maximum
if you use the maximum pixel value as the "Noise Tolerance". Here is a
macro the uses Find Maxima to display the location and value of the
image maximum.

    getRawStatistics(nPixels, mean, min, max);
    run("Find Maxima...", "noise="+max+" output=[Point Selection]");
    getSelectionBounds(x, y, w, h);
    print("coordinates=("+x+","+y+"), value="+getPixel(x,y));

-wayne