How to Align two images

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I am new to OpenCV and I need some help ..

Objective : I am trying to highlight the difference between two images

Problem : If the images differ in the position , the program highlights the whole image

How can I Align the images so that each feature in one image will be placed on the same feature in the second image , and eventually remove the outliers.

I used the following steps :

1. import the 2 images
2. convert them into grayScale
3. get the features by Feature-detector
4. use Find Homograpy
5. Use Absdiff
6. Highlight the difference

I been told to use WarpPrescriptive but I didn't know how to use it

If anyone can help me please