[Insight-users] How to equalize the brightness of sequential images?

[Luis Ibanez]

Hi Fucang,

Using only luminance may be an insufficient criterion for
normalizing your images.

You may want to use the more formal approach of HistogramMatching.
http://www.itk.org/Insight/Doxygen/html/classitk_1_1HistogramMatchingImageFilter.html

This filter will correct the intensities of one image in such
a way that its histogram will better match the histogram of
another image provided as a reference.

This is a gray level concept, so, what you may do,  is to convert
your color images to luminance images, match the histograms of the
luminance images among them, and then use the correction factors
for normalizing the original color images.

This approach will correct different color using different factors.
That will allow you to concentrate the correction to the objects
that you consider important in your image.

Please let us know if you have further questions,


Thanks


Luis

--------------------

Fucang Jia wrote:
> Hi Luis, hi everyone,
> 
> I am encoutering a problem, there are some serial section images, which 
> were scanned by a digital camera. Due to the collection was not done in 
> the same time and the background light are not the same. This problem 
> does not affect registration in fact. But it affect the segmentation. I 
> use Rescale and Normalize filter to adjust the image brightness, but the 
> result seems not good. I wonder to know if there exists good method to 
> equalize the brightness. And firstly, how to compute the brightness of 
> an image, should convert RGB colorspace to HSV one and then compute the 
> mean of V(value), or convert to HLS colorspace and compute the mean of 
> the Lightness?
> 
> Thanks a lot!
> 
> Fucang
> 
> 
> 
> 
> 
> 
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