How to align two images

I want to align these two images, but as you can see they have different color, but I want it to be in the same shape/direction for further image processing

Answer 1

[Ameer Hamza]

You are trying to do image registeration: https://en.wikipedia.org/wiki/Image_registration

Following MATLAB resources will be helpful:

https://www.mathworks.com/discovery/image-registration.html

https://www.mathworks.com/help/images/image-registration.html

Especially check these functions

https://www.mathworks.com/help/images/ref/imregcorr.html

https://www.mathworks.com/help/images/ref/imregister.html

[Thomas Taufan]

Could you try to register these two images? When I tried the registration codes from one of your reference the result is not aligned well

https://www.mathworks.com/help/images/ref/imregcorr.html

a = imread('Picture 172.jpg');
b = imread('Picture 173.jpg');
tformEstimate = imregcorr(a,b);
Rfixed = imref2d(size(a));
movingReg = imwarp(b,tformEstimate,'OutputView',Rfixed);
imshowpair(a,movingReg,'falsecolor');

[Image Analyst]

Which two? The 'Picture 172.jpg' and 'Picture 173.jpg' that you forgot to attach?

[Thomas Taufan]

I'm sorry, I used another set of photo in my first question

[Ameer Hamza]

imregister() seems to work well in this case

a = rgb2gray(imread('image1.jpeg'));
b = rgb2gray(imread('image2.jpeg'));
[optimizer, metric] = imregconfig('multimodal');
im_reg = imregister(a, b, 'affine', optimizer, metric);
imshowpair(b, im_reg,'falsecolor');

[Thomas Taufan]

Thanks for your answer, I have tried it as well, and as I see there is still some deviation between the two images. As I need to calculate both of them, I'm afraid there will be some error in the mispositioning of the plant or leafs.

[Ameer Hamza]

You may try tuning the optimizer and metric parameters, as shown on the documentation page of imregister() and imregconfig(). However, I don't think that pixel-level registration is easily possible. There will be some differences if looked closely.

[Image Analyst]

Yes, of course. If the camera location and angle change, eventually the views will be so drastically different that it won't even be possible to register them. The smaller the movement, the better the alignment and the fewer the "bad" pixels. How good or bad the registration is depends on how much the camera moved and how much the subject moved (e.g. was it windy and the leaves moved?).