# After Resampling Process Applying Bias Field Correction
**URL:** https://discourse.itk.org/t/after-resampling-process-applying-bias-field-correction/4479
**Category:** Community
**Tags:** simpleitk
**Created:** [October 6, 2021, 7:09am UTC](https://discourse.itk.org/t/after-resampling-process-applying-bias-field-correction/4479 "2021-10-06T07:09:14Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Furkan\_Gokhan](https://discourse.itk.org/u/Furkan_Gokhan)
#### Post date: [October 6, 2021, 7:09am UTC](https://discourse.itk.org/t/after-resampling-process-applying-bias-field-correction/4479/1 "2021-10-06T07:09:14Z")
Hello everyone,
I am using SimpleITK library for bias field correction algorithm to preprocess on MR images but this is very time consuming because MR image ussualy has high dimension such as 152,640,640 pixel array. I want to ask that :
Is it correct to apply bias field correction after performing the resampling process first? Is this cause a problem?
Best Regards.
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### Author:  [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [October 6, 2021, 1:36pm UTC](https://discourse.itk.org/t/after-resampling-process-applying-bias-field-correction/4479/2 "2021-10-06T13:36:00Z")
Short answer: it is not a big problem.
While it is logical to do bias field correction on the smaller image (which is probably the resampled one), resampling first and then doing bias correction will lead to slightly lower image quality. Since bias field is assumed to continuous and slow changing, it can be done on a down-scaled image, see an [example](https://github.com/InsightSoftwareConsortium/ITKMontage/blob/v0.7.3/examples/CompleteMontage.cxx#L410-L411). So you should first apply bias correction and then resampling, even if you estimate the bias correction on a downscaled version of the original image.
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### Author:  [@Furkan\_Gokhan](https://discourse.itk.org/u/Furkan_Gokhan)
#### Post date: [October 7, 2021, 11:17am UTC](https://discourse.itk.org/t/after-resampling-process-applying-bias-field-correction/4479/3 "2021-10-07T11:17:05Z")
Thanks for your comment.