How to perform image registration with an alpha channel











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I have two images and would like to perform feature detection on both and match these features. My problem is that the second image is a section of the first image with missing pixels. These missing pixels cause a strong discontinuity in the pixel intensity causing the feature detectors to place all features at this boundary as such:



enter image description here



Because of this the feature matching program fails since (i think) the descriptor of these features contain the missing pixel intensities which don't exist in the original image. As such i would like the feature detector to exclude these features and instead search within the 'valid' pixel regions. Does anyone have an idea ?



Else how, maybe using pattern matching on the pixel intensity could be a strong alternative but i can't find an efficient implementation for this (especially considering that the two images may be rotated with respect to one another).



[EDIT] Here are the two images:



enter image description hereOriginal image










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  • 2




    Do you have the 2 starting images as well please?
    – Mark Setchell
    yesterday










  • I just added them in an edit.
    – Guillaume
    yesterday










  • You can't fool me that easily! That's one image with no transparent pixels...
    – Mark Setchell
    yesterday










  • I tried... here are the actual images
    – Guillaume
    yesterday










  • What do you mean by "feature matching program". Maybe you can customize it to reject the features on the boundary and not the weaker ones in the valid area.
    – Knipser
    yesterday

















up vote
1
down vote

favorite












I have two images and would like to perform feature detection on both and match these features. My problem is that the second image is a section of the first image with missing pixels. These missing pixels cause a strong discontinuity in the pixel intensity causing the feature detectors to place all features at this boundary as such:



enter image description here



Because of this the feature matching program fails since (i think) the descriptor of these features contain the missing pixel intensities which don't exist in the original image. As such i would like the feature detector to exclude these features and instead search within the 'valid' pixel regions. Does anyone have an idea ?



Else how, maybe using pattern matching on the pixel intensity could be a strong alternative but i can't find an efficient implementation for this (especially considering that the two images may be rotated with respect to one another).



[EDIT] Here are the two images:



enter image description hereOriginal image










share|improve this question




















  • 2




    Do you have the 2 starting images as well please?
    – Mark Setchell
    yesterday










  • I just added them in an edit.
    – Guillaume
    yesterday










  • You can't fool me that easily! That's one image with no transparent pixels...
    – Mark Setchell
    yesterday










  • I tried... here are the actual images
    – Guillaume
    yesterday










  • What do you mean by "feature matching program". Maybe you can customize it to reject the features on the boundary and not the weaker ones in the valid area.
    – Knipser
    yesterday















up vote
1
down vote

favorite









up vote
1
down vote

favorite











I have two images and would like to perform feature detection on both and match these features. My problem is that the second image is a section of the first image with missing pixels. These missing pixels cause a strong discontinuity in the pixel intensity causing the feature detectors to place all features at this boundary as such:



enter image description here



Because of this the feature matching program fails since (i think) the descriptor of these features contain the missing pixel intensities which don't exist in the original image. As such i would like the feature detector to exclude these features and instead search within the 'valid' pixel regions. Does anyone have an idea ?



Else how, maybe using pattern matching on the pixel intensity could be a strong alternative but i can't find an efficient implementation for this (especially considering that the two images may be rotated with respect to one another).



[EDIT] Here are the two images:



enter image description hereOriginal image










share|improve this question















I have two images and would like to perform feature detection on both and match these features. My problem is that the second image is a section of the first image with missing pixels. These missing pixels cause a strong discontinuity in the pixel intensity causing the feature detectors to place all features at this boundary as such:



enter image description here



Because of this the feature matching program fails since (i think) the descriptor of these features contain the missing pixel intensities which don't exist in the original image. As such i would like the feature detector to exclude these features and instead search within the 'valid' pixel regions. Does anyone have an idea ?



Else how, maybe using pattern matching on the pixel intensity could be a strong alternative but i can't find an efficient implementation for this (especially considering that the two images may be rotated with respect to one another).



[EDIT] Here are the two images:



enter image description hereOriginal image







matlab image-processing pattern-matching feature-detection image-registration






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited yesterday

























asked yesterday









Guillaume

155




155








  • 2




    Do you have the 2 starting images as well please?
    – Mark Setchell
    yesterday










  • I just added them in an edit.
    – Guillaume
    yesterday










  • You can't fool me that easily! That's one image with no transparent pixels...
    – Mark Setchell
    yesterday










  • I tried... here are the actual images
    – Guillaume
    yesterday










  • What do you mean by "feature matching program". Maybe you can customize it to reject the features on the boundary and not the weaker ones in the valid area.
    – Knipser
    yesterday
















  • 2




    Do you have the 2 starting images as well please?
    – Mark Setchell
    yesterday










  • I just added them in an edit.
    – Guillaume
    yesterday










  • You can't fool me that easily! That's one image with no transparent pixels...
    – Mark Setchell
    yesterday










  • I tried... here are the actual images
    – Guillaume
    yesterday










  • What do you mean by "feature matching program". Maybe you can customize it to reject the features on the boundary and not the weaker ones in the valid area.
    – Knipser
    yesterday










2




2




Do you have the 2 starting images as well please?
– Mark Setchell
yesterday




Do you have the 2 starting images as well please?
– Mark Setchell
yesterday












I just added them in an edit.
– Guillaume
yesterday




I just added them in an edit.
– Guillaume
yesterday












You can't fool me that easily! That's one image with no transparent pixels...
– Mark Setchell
yesterday




You can't fool me that easily! That's one image with no transparent pixels...
– Mark Setchell
yesterday












I tried... here are the actual images
– Guillaume
yesterday




I tried... here are the actual images
– Guillaume
yesterday












What do you mean by "feature matching program". Maybe you can customize it to reject the features on the boundary and not the weaker ones in the valid area.
– Knipser
yesterday






What do you mean by "feature matching program". Maybe you can customize it to reject the features on the boundary and not the weaker ones in the valid area.
– Knipser
yesterday














1 Answer
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If you slide the "holey" image over the solid one, and difference them, they will be aligned when you have the maximum number of black pixels. Watch for the magenta diagonal to disappear.



enter image description here






share|improve this answer





















  • Thank you for your response. I like the idea, sounds very practical in this scenario as the reference image is of the same height which is usually not the case... Additionally I would need my algorithm to be invariant to rotation. I will try to implement your idea on a non-ideal case (where the height and relative rotation are different) but i fear the efficiency and computation time will take a hit.
    – Guillaume
    14 hours ago











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1 Answer
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active

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1 Answer
1






active

oldest

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active

oldest

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active

oldest

votes








up vote
1
down vote













If you slide the "holey" image over the solid one, and difference them, they will be aligned when you have the maximum number of black pixels. Watch for the magenta diagonal to disappear.



enter image description here






share|improve this answer





















  • Thank you for your response. I like the idea, sounds very practical in this scenario as the reference image is of the same height which is usually not the case... Additionally I would need my algorithm to be invariant to rotation. I will try to implement your idea on a non-ideal case (where the height and relative rotation are different) but i fear the efficiency and computation time will take a hit.
    – Guillaume
    14 hours ago















up vote
1
down vote













If you slide the "holey" image over the solid one, and difference them, they will be aligned when you have the maximum number of black pixels. Watch for the magenta diagonal to disappear.



enter image description here






share|improve this answer





















  • Thank you for your response. I like the idea, sounds very practical in this scenario as the reference image is of the same height which is usually not the case... Additionally I would need my algorithm to be invariant to rotation. I will try to implement your idea on a non-ideal case (where the height and relative rotation are different) but i fear the efficiency and computation time will take a hit.
    – Guillaume
    14 hours ago













up vote
1
down vote










up vote
1
down vote









If you slide the "holey" image over the solid one, and difference them, they will be aligned when you have the maximum number of black pixels. Watch for the magenta diagonal to disappear.



enter image description here






share|improve this answer












If you slide the "holey" image over the solid one, and difference them, they will be aligned when you have the maximum number of black pixels. Watch for the magenta diagonal to disappear.



enter image description here







share|improve this answer












share|improve this answer



share|improve this answer










answered 18 hours ago









Mark Setchell

83.9k569169




83.9k569169












  • Thank you for your response. I like the idea, sounds very practical in this scenario as the reference image is of the same height which is usually not the case... Additionally I would need my algorithm to be invariant to rotation. I will try to implement your idea on a non-ideal case (where the height and relative rotation are different) but i fear the efficiency and computation time will take a hit.
    – Guillaume
    14 hours ago


















  • Thank you for your response. I like the idea, sounds very practical in this scenario as the reference image is of the same height which is usually not the case... Additionally I would need my algorithm to be invariant to rotation. I will try to implement your idea on a non-ideal case (where the height and relative rotation are different) but i fear the efficiency and computation time will take a hit.
    – Guillaume
    14 hours ago
















Thank you for your response. I like the idea, sounds very practical in this scenario as the reference image is of the same height which is usually not the case... Additionally I would need my algorithm to be invariant to rotation. I will try to implement your idea on a non-ideal case (where the height and relative rotation are different) but i fear the efficiency and computation time will take a hit.
– Guillaume
14 hours ago




Thank you for your response. I like the idea, sounds very practical in this scenario as the reference image is of the same height which is usually not the case... Additionally I would need my algorithm to be invariant to rotation. I will try to implement your idea on a non-ideal case (where the height and relative rotation are different) but i fear the efficiency and computation time will take a hit.
– Guillaume
14 hours ago


















 

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