Re: Enhance Contrast with 16 bit images only uses 256 bins

Posted by Charles Brossollet-2 on Dec 02, 2010; 3:18pm
URL: http://imagej.273.s1.nabble.com/Enhance-Contrast-with-16-bit-images-only-uses-256-bins-tp3686304p3686307.html

Michael,

Thanks but your macro modifies the image, and you'd have to select a different area for a different image... This is not ideal for me.

Cheers,
Charles

Le 2 déc. 2010 à 14:36, Cammer, Michael a écrit :

> How about:
> run("Median...", "radius=0.5");
> makeOval(488, 595, 34, 37);
> run("Measure");
> run("Subtract...", "value=48");
> run("Gamma...", "value=something you like
> run("Brightness/Contrast...");
>
> -----Original Message-----
> From: ImageJ Interest Group [mailto:[hidden email]] On Behalf Of Charles Brossollet
> Sent: Thursday, December 02, 2010 4:46 AM
> To: [hidden email]
> Subject: Enhance Contrast with 16 bit images only uses 256 bins
>
> Hello,
>
> I have problems using contrast enhancement on 16 bit gray-level images. My
> images have 99% of pixel values in the 5% of true min-max range, so an
> histogram with 256 bins will have huge pixel counts on a few bins. This
> gives inappropriate contrast enhancement since it seems that ImageJ uses 256
> bin histogram for this function.
>
> I have an example image here:
> http://dl.dropbox.com/u/2539804/TD1.tif
>
> Good LUT range for this image is about 5 to 250 levels, but the "enhance
> contrast" with 0,35 gives 3 to 743, leading to a poorly contrasted display.
> INMHO computing histogram on more bins should solve the problem.
>
> Best regards,
> Charles
>
> ------------------------------------------------------------
> This email message, including any attachments, is for the sole use of the intended recipient(s) and may contain information that is proprietary, confidential, and exempt from disclosure under applicable law. Any unauthorized review, use, disclosure, or distribution is prohibited. If you have received this email in error please notify the sender by return email and delete the original message. Please note, the recipient should check this email and any attachments for the presence of viruses. The organization accepts no liability for any damage caused by any virus transmitted by this email.
> =================================