Friday, December 12, 2014

Analyze: Width Distribution using EDM



 Estimating the largest width as in the previous post [Link] is interesting but in most cases, we want a distribution of widths...

Analyze: Calculating the width of an object



After the length [Link], the other important parameter to measure is the width of the object of interest. This can be deduced from the euclidean distance map (EDM). Here are some examples...

Thursday, December 11, 2014

Analyze: Pixel connectivity - Part II



Second part about pixel connectivity. How to precisely measure a length by counting pixels with Analyze > Analyze Particles... ?


Monday, December 8, 2014

Analyze: Pixel connectivity



In a previous post [Link], we were able to measure a distance between two points or the length of a sample by counting the number of pixels thanks to Analyze > Analyze Particles... . However, the result is directly dependent of the pixel connectivity...

Enhancement: Subtract Background



In ImageJ, non uniform illumination may be corrected with the function Process > Subtract Background...

Enhancement: Non uniform illumination





In the Image Enhancement series, the non uniform illumination is the second main defect that you must correct in your images.

Friday, December 5, 2014

Gray-level images



In this series dedicated to digital image, gray level images are the most common images used in ImageJ.


Enhancement: Brightness/Contrast and Histogram



The previous method based on the transfer function [Link] is powerful but you have to manually define the slope and the y-intercept of the transfer function. It is faster to directly modify the histogram.

Enhancement: Brightness/Contrast and Transfer Function



The brightness and contrast of an image can be enhanced by modifying the transfer function or playing with the pixel distribution of the histogram. Here is the first part with the transfer function...

Image Enhancement: TOC



Table of Contents of the series of posts dedicated to Image Enhancement.

Measuring the length of a sample


One of the simplest parameter to measure in a segmented - binary - image is the length of your sample (a molecule, cellular or subcellular components, fibers, etc.).
I'll describe two techniques (manual and automatic) to get such information.