any function to do CLAHE ?

[Forrestwang1]

Dear aoles, Is there any function in this package to do CLAHE (contrast limited adaptive histogram equalization)? I know this following function only doing hist.eq for the whole image. equalize(x) Thanks, Forrest

[aoles]

Hi, thank you for your interest in EBImage! We don't have a function for doing contrast limited adaptive histogram equalization, but it should be in principle possible to integrate the code from https://github.com/erich666/GraphicsGems/blob/master/gemsiv/clahe.c into the package. May I ask what would be your use case of performing CLAHE?

Cheers, Andrzej

[Forrestwang1]

Thanks for your quick reply! I have used EBImage for a while. I am trying to use CLAHE for a project which is still related medial image. The function of equalize(x) is good for most of them, but sometimes some images really need CLAHE to enhance the picture.

[Forrestwang1]

I just opened the link which seems using C, I have no any knowledge about language C. thanks anyway~ .

[aoles]

Thanks for your feedback!

I will then look into the possibility of adding a function for performing CLAHE based on the code from clahe.c, so stay tuned.

[Forrestwang1]

thanks so much for your consideration, I will wait for that and will check the package everyday~~,thanks again~

[aoles]

You're very welcome, I will keep you updated on the progress.

[Forrestwang1]

thanks~

[aoles]

Hi, I'm happy to inform you that I've managed to integrate into EBImage Karel Zuiderveld's implementation of CLAHE. You can perform the filtering as follows.

Please let me know whether this works for you as expected.

Cheers, Andrzej

# input image containing multiple frames
x = readImage(system.file("images", "cells.tif", package="EBImage"))
display(x, method="raster", all=TRUE)

# perform contrast limited adaptive histogram equalization
y = clahe(x, nx=5, ny=5)
display(y, method="raster", all=TRUE)

[Forrestwang1]

wow, you are so fast~ I cannot wait to try and thanks a lot!!!!!!!!!!!!!!!!!!!

[Forrestwang1]

It seems that I have trouble to update the package~any suggestion?

[aoles]

# install.packages("devtools")
devtools::install_github("aoles/EBImage")

[Forrestwang1]

got it, thanks~~~~

[Forrestwang1]

just now I randomly run the code x = readImage(system.file("images", "cells.tif", package="EBImage")) display(x, method="raster", all=TRUE) it shows that Error in transpose(y) : object 'C_transpose' not found

[Forrestwang1]

Hey aoles, I reinstalled R and tried several images again and it works perfect, thanks~