How to convert a 4-channel image to 3-channel image in an elegant way?












5












$begingroup$


I have a 4-channel image (RGBA). I want to reduce its channel count from 4 to 3.



The method I am using currently is to Right click and Save as a .png file. After that when I Import it in Mathematica, the channel count is reduced to 3. Is there a more elegant way to do that?



Note: RemoveAlphaChannel function won't work. Because that will change the appearance of the original image (see the example below).



This is a 4-channel picture from ref / AlphaChannel:



4-channel picture



 img = Import @ "https://i.stack.imgur.com/XvzDc.png"


This is the 3-channel picture which is what I want:



3-channel picture



If I use RemoveAlphaChannel, I will get this picture instead:



Picture after RemoveAlphaChannel






image-processing image







share|improve this question











$endgroup$








  • 3




    $begingroup$
    does RemoveAlphaChannel[img, White] not work for you? it does give 3-channel image ( ImageChannels@RemoveAlphaChannel[img, White] is 3).
    $endgroup$
    – kglr
    1 hour ago












  • $begingroup$
    @kglr Yes it works for that situation. It's amazing, thank you.
    $endgroup$
    – Voldikss
    50 mins ago
















5












$begingroup$


I have a 4-channel image (RGBA). I want to reduce its channel count from 4 to 3.



The method I am using currently is to Right click and Save as a .png file. After that when I Import it in Mathematica, the channel count is reduced to 3. Is there a more elegant way to do that?



Note: RemoveAlphaChannel function won't work. Because that will change the appearance of the original image (see the example below).



This is a 4-channel picture from ref / AlphaChannel:



4-channel picture



 img = Import @ "https://i.stack.imgur.com/XvzDc.png"


This is the 3-channel picture which is what I want:



3-channel picture



If I use RemoveAlphaChannel, I will get this picture instead:



Picture after RemoveAlphaChannel






image-processing image







share|improve this question











$endgroup$








  • 3




    $begingroup$
    does RemoveAlphaChannel[img, White] not work for you? it does give 3-channel image ( ImageChannels@RemoveAlphaChannel[img, White] is 3).
    $endgroup$
    – kglr
    1 hour ago












  • $begingroup$
    @kglr Yes it works for that situation. It's amazing, thank you.
    $endgroup$
    – Voldikss
    50 mins ago














5












5








5


1



$begingroup$


I have a 4-channel image (RGBA). I want to reduce its channel count from 4 to 3.



The method I am using currently is to Right click and Save as a .png file. After that when I Import it in Mathematica, the channel count is reduced to 3. Is there a more elegant way to do that?



Note: RemoveAlphaChannel function won't work. Because that will change the appearance of the original image (see the example below).



This is a 4-channel picture from ref / AlphaChannel:



4-channel picture



 img = Import @ "https://i.stack.imgur.com/XvzDc.png"


This is the 3-channel picture which is what I want:



3-channel picture



If I use RemoveAlphaChannel, I will get this picture instead:



Picture after RemoveAlphaChannel






image-processing image







share|improve this question











$endgroup$




I have a 4-channel image (RGBA). I want to reduce its channel count from 4 to 3.



The method I am using currently is to Right click and Save as a .png file. After that when I Import it in Mathematica, the channel count is reduced to 3. Is there a more elegant way to do that?



Note: RemoveAlphaChannel function won't work. Because that will change the appearance of the original image (see the example below).



This is a 4-channel picture from ref / AlphaChannel:



4-channel picture



 img = Import @ "https://i.stack.imgur.com/XvzDc.png"


This is the 3-channel picture which is what I want:



3-channel picture



If I use RemoveAlphaChannel, I will get this picture instead:



Picture after RemoveAlphaChannel






image-processing image




image-processing image






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited 34 mins ago









Andreas Rejbrand

10314




10314










asked 1 hour ago









VoldikssVoldikss

357




357








  • 3




    $begingroup$
    does RemoveAlphaChannel[img, White] not work for you? it does give 3-channel image ( ImageChannels@RemoveAlphaChannel[img, White] is 3).
    $endgroup$
    – kglr
    1 hour ago












  • $begingroup$
    @kglr Yes it works for that situation. It's amazing, thank you.
    $endgroup$
    – Voldikss
    50 mins ago














  • 3




    $begingroup$
    does RemoveAlphaChannel[img, White] not work for you? it does give 3-channel image ( ImageChannels@RemoveAlphaChannel[img, White] is 3).
    $endgroup$
    – kglr
    1 hour ago












  • $begingroup$
    @kglr Yes it works for that situation. It's amazing, thank you.
    $endgroup$
    – Voldikss
    50 mins ago








3




3




$begingroup$
does RemoveAlphaChannel[img, White] not work for you? it does give 3-channel image ( ImageChannels@RemoveAlphaChannel[img, White] is 3).
$endgroup$
– kglr
1 hour ago






$begingroup$
does RemoveAlphaChannel[img, White] not work for you? it does give 3-channel image ( ImageChannels@RemoveAlphaChannel[img, White] is 3).
$endgroup$
– kglr
1 hour ago














$begingroup$
@kglr Yes it works for that situation. It's amazing, thank you.
$endgroup$
– Voldikss
50 mins ago




$begingroup$
@kglr Yes it works for that situation. It's amazing, thank you.
$endgroup$
– Voldikss
50 mins ago










1 Answer
1






active

oldest

votes


















6












$begingroup$

The second example from RemoveAlphaChannel:





  • Remove opacity by blending with a white background:






img2 = RemoveAlphaChannel[img, White]


enter image description here



ImageChannels /@ {img, img2}



{4, 3}




ColorSeparate /@ {img, img2} // Grid


enter image description here



Row[{Labeled[Framed@AlphaChannel@img, "img", Top], 

     Labeled[Framed@AlphaChannel@img2, "img2", Top]}]


enter image description here






share|improve this answer











$endgroup$













  • $begingroup$
    Thank you very much @kglr. I wonder if RemoveAlphaChannel[#, White]& is universal. If it also works for various alpha channels. (I've tried some pictures with different alpha channels and it works, but I am still not sure whether it works for all the cases...)
    $endgroup$
    – Voldikss
    53 mins ago












  • $begingroup$
    @VoldikSS, I am not sure if it works for all cases.
    $endgroup$
    – kglr
    43 mins ago











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1 Answer
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oldest

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1 Answer
1






active

oldest

votes









active

oldest

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active

oldest

votes









6












$begingroup$

The second example from RemoveAlphaChannel:





  • Remove opacity by blending with a white background:






img2 = RemoveAlphaChannel[img, White]


enter image description here



ImageChannels /@ {img, img2}



{4, 3}




ColorSeparate /@ {img, img2} // Grid


enter image description here



Row[{Labeled[Framed@AlphaChannel@img, "img", Top], 

     Labeled[Framed@AlphaChannel@img2, "img2", Top]}]


enter image description here






share|improve this answer











$endgroup$













  • $begingroup$
    Thank you very much @kglr. I wonder if RemoveAlphaChannel[#, White]& is universal. If it also works for various alpha channels. (I've tried some pictures with different alpha channels and it works, but I am still not sure whether it works for all the cases...)
    $endgroup$
    – Voldikss
    53 mins ago












  • $begingroup$
    @VoldikSS, I am not sure if it works for all cases.
    $endgroup$
    – kglr
    43 mins ago
















6












$begingroup$

The second example from RemoveAlphaChannel:





  • Remove opacity by blending with a white background:






img2 = RemoveAlphaChannel[img, White]


enter image description here



ImageChannels /@ {img, img2}



{4, 3}




ColorSeparate /@ {img, img2} // Grid


enter image description here



Row[{Labeled[Framed@AlphaChannel@img, "img", Top], 

     Labeled[Framed@AlphaChannel@img2, "img2", Top]}]


enter image description here






share|improve this answer











$endgroup$













  • $begingroup$
    Thank you very much @kglr. I wonder if RemoveAlphaChannel[#, White]& is universal. If it also works for various alpha channels. (I've tried some pictures with different alpha channels and it works, but I am still not sure whether it works for all the cases...)
    $endgroup$
    – Voldikss
    53 mins ago












  • $begingroup$
    @VoldikSS, I am not sure if it works for all cases.
    $endgroup$
    – kglr
    43 mins ago














6












6








6





$begingroup$

The second example from RemoveAlphaChannel:





  • Remove opacity by blending with a white background:






img2 = RemoveAlphaChannel[img, White]


enter image description here



ImageChannels /@ {img, img2}



{4, 3}




ColorSeparate /@ {img, img2} // Grid


enter image description here



Row[{Labeled[Framed@AlphaChannel@img, "img", Top], 

     Labeled[Framed@AlphaChannel@img2, "img2", Top]}]


enter image description here






share|improve this answer











$endgroup$



The second example from RemoveAlphaChannel:





  • Remove opacity by blending with a white background:






img2 = RemoveAlphaChannel[img, White]


enter image description here



ImageChannels /@ {img, img2}



{4, 3}




ColorSeparate /@ {img, img2} // Grid


enter image description here



Row[{Labeled[Framed@AlphaChannel@img, "img", Top], 

     Labeled[Framed@AlphaChannel@img2, "img2", Top]}]


enter image description here







share|improve this answer














share|improve this answer



share|improve this answer








edited 1 hour ago

























answered 1 hour ago









kglrkglr

180k9200413




180k9200413












  • $begingroup$
    Thank you very much @kglr. I wonder if RemoveAlphaChannel[#, White]& is universal. If it also works for various alpha channels. (I've tried some pictures with different alpha channels and it works, but I am still not sure whether it works for all the cases...)
    $endgroup$
    – Voldikss
    53 mins ago












  • $begingroup$
    @VoldikSS, I am not sure if it works for all cases.
    $endgroup$
    – kglr
    43 mins ago


















  • $begingroup$
    Thank you very much @kglr. I wonder if RemoveAlphaChannel[#, White]& is universal. If it also works for various alpha channels. (I've tried some pictures with different alpha channels and it works, but I am still not sure whether it works for all the cases...)
    $endgroup$
    – Voldikss
    53 mins ago












  • $begingroup$
    @VoldikSS, I am not sure if it works for all cases.
    $endgroup$
    – kglr
    43 mins ago
















$begingroup$
Thank you very much @kglr. I wonder if RemoveAlphaChannel[#, White]& is universal. If it also works for various alpha channels. (I've tried some pictures with different alpha channels and it works, but I am still not sure whether it works for all the cases...)
$endgroup$
– Voldikss
53 mins ago






$begingroup$
Thank you very much @kglr. I wonder if RemoveAlphaChannel[#, White]& is universal. If it also works for various alpha channels. (I've tried some pictures with different alpha channels and it works, but I am still not sure whether it works for all the cases...)
$endgroup$
– Voldikss
53 mins ago














$begingroup$
@VoldikSS, I am not sure if it works for all cases.
$endgroup$
– kglr
43 mins ago




$begingroup$
@VoldikSS, I am not sure if it works for all cases.
$endgroup$
– kglr
43 mins ago


















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