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How do I increase this image's resolution?

Discussion in 'Computers and Networks' started by siyom, Oct 23, 2015.

  1. siyom

    siyom Member

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    compressed.JPG This image looks to have had its resolution reduced by a factor of 8 after going through DCT compression,how do I increase its resolution so that its stops the blurriness.
     

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    Last edited: Oct 23, 2015
    siyom, Oct 23, 2015
    #1
  2. Ian Rogers

    Ian Rogers User Extraordinaire Forum Supporter Most Helpful Member

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    It doesn't look blurry to me!!!! I can't see it!!
     
    Ian Rogers, Oct 23, 2015
    #2
    • Agree Agree x 1
  3. DerStrom8

    DerStrom8 Super Moderator Most Helpful Member

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    Same here:

    upload_2015-10-23_7-58-11.png
     
    DerStrom8, Oct 23, 2015
    #3
  4. dave miyares

    Dave New Member

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    Dave, Feb 30, 2018
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  5. siyom

    siyom Member

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    compressed.JPG
    compressed.png
     
    siyom, Oct 23, 2015
    #4
  6. siyom

    siyom Member

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    Sorry about that,I couldn't figure out how to upload images here,I've re uploaded the image
     
    siyom, Oct 23, 2015
    #5
  7. Ian Rogers

    Ian Rogers User Extraordinaire Forum Supporter Most Helpful Member

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    Resolution is lost!!!! Unless you have the original... Photoshop can approximate but the blurriness will always be there.

    Do you not have the original???
     
    Ian Rogers, Oct 23, 2015
    #6
  8. dave miyares

    Dave New Member

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    Dave, Feb 30, 2018
    #6.1415
  9. Ian Rogers

    Ian Rogers User Extraordinaire Forum Supporter Most Helpful Member

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    This is about as good as I could do in the time...

    upload_2015-10-23_14-0-17.png
     
    Ian Rogers, Oct 23, 2015
    #7
    • Like Like x 1
  10. siyom

    siyom Member

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    yes I have the original, how is resolution lost?I did this in matlab and I am not sure if photoshop would be permissible in this instance.
    Could this mean there's something wrong with my code?
    I was doing DCT compression btw.
     
    siyom, Oct 23, 2015
    #8
  11. Ian Rogers

    Ian Rogers User Extraordinaire Forum Supporter Most Helpful Member

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    If you compress a file down to "x" resolution and maintain the picture quality... It's impossible to go back...

    If you are trying to save memory space, consider encoding... There are many ways of retaining the picture details.

    You need a decent picture encoding C routine.. Jpeg or Gif
     
    Ian Rogers, Oct 23, 2015
    #9
  12. Andrei_D12

    Andrei_D12 Active Member

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    Hi!
    For uploading images you can use Imgur. There you can upload from your computer and you can share it with many link variants (BB Code, link, short link,...). This is how I post images in this forum (BB code for forums).
    Compression is not a recommended thing to do with an image that you are going to use in full size. Compression is useful only when you need the image in small size (for example you want to use that image as a profile photo and the size of the picture is larger than the maximum allowed). The quality of the image after compression is dependent on the photo editor, but generally the quality is lost...

    Andrei
     
    Andrei_D12, Oct 23, 2015
    #10
  13. siyom

    siyom Member

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    Ok I get you, so this might be because I didn't encode the image
     
    siyom, Oct 23, 2015
    #11
  14. Ian Rogers

    Ian Rogers User Extraordinaire Forum Supporter Most Helpful Member

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    Are you trying to save memory space by DCT compression??? I thought it was mainly for audio not picture as its Discreet Cosine Transformation.... I know it has been used but surely JPEG would be easier...

    If you are encoding a picture BUT!! on decoding the image is as your photo, then yes! You have an issue in your code!!
     
    Ian Rogers, Oct 23, 2015
    #12
  15. crutschow

    crutschow Well-Known Member Most Helpful Member

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    If you don't want to lose any image information when you compress it then you need to use a lossless image compression method such as PNG.
    Such methods don't provide as much compression as the lossy ones, such as JPEG (which uses DCT), but they retain all the image information.
     
    crutschow, Oct 23, 2015
    #13
  16. Andrei_D12

    Andrei_D12 Active Member

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    True!
     
    Andrei_D12, Oct 23, 2015
    #14
  17. Inquisitive

    Inquisitive Super Moderator

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    lena_gray.gif

    lena_color.gif
     
    Inquisitive, Oct 23, 2015
    #15
  18. Andrei_D12

    Andrei_D12 Active Member

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    How beautiful... Where have you found them???
     
    Andrei_D12, Oct 23, 2015
    #16
  19. Inquisitive

    Inquisitive Super Moderator

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    Google images search for "lena" she has been on the internet for a while.
     
    Inquisitive, Oct 23, 2015
    #17
  20. Andrei_D12

    Andrei_D12 Active Member

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    Lena...
    I bet she's actress or photomodel or something...
    Singer... I found some videos with her !
     
    Andrei_D12, Oct 23, 2015
    #18
  21. atferrari

    atferrari Well-Known Member

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    First time I saw that image was in the Don Lancaster's colum in the US ???? magazine. He used it precisely to discuss something like resolution, grey scales or related with that.

    Maybe you could find it in his site.
     
    atferrari, Oct 23, 2015
    #19
  22. Inquisitive

    Inquisitive Super Moderator

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    Inquisitive, Oct 23, 2015
    #20

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