# a question aobout itkSimilarityIndexImageFilter

**URL:** https://discourse.itk.org/t/a-question-aobout-itksimilarityindeximagefilter/5995
**Category:** Beginner Questions
**Created:** [June 16, 2023, 4:57pm UTC](https://discourse.itk.org/t/a-question-aobout-itksimilarityindeximagefilter/5995 "2023-06-16T16:57:00Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![xiaohoua](https://discourse.itk.org/letter_avatar_proxy/v4/letter/x/7ba0ec/32.png) [@xiaohoua](https://discourse.itk.org/u/xiaohoua)
#### Post date: [June 16, 2023, 4:57pm UTC](https://discourse.itk.org/t/a-question-aobout-itksimilarityindeximagefilter/5995/1 "2023-06-16T16:57:00Z")

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Recently, I was studying about ITK and used `itksimilarityimageindexfilter` 。

I wonder if this filter has any requirements for two input images? For example, does it need two images to be the same size?And What would it do with two images of different sizes？