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How do I enhance low quality JPEG images?

by ElliotSmith
Tags: enhance, images, jpeg, quality
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ElliotSmith
#1
Sep3-14, 08:04 PM
P: 3
Is there any way to enhance low quality and low resolution JPEG images? Is there a program I can use or something?

I have dozens of grainy and poor quality JPEGs that I would like to sharpen up, but I do not own photoshop.
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Greg Bernhardt
#2
Sep3-14, 08:20 PM
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Enhancing low quality photos is tough because you need some algorithm to add in data to the image that didn't exist. Photoshop does have some advanced tools for this. Free options do exist but I'm not sure how much they will help. Certainly sharpen filters are common though.

Try http://www.getpaint.net
FactChecker
#3
Sep3-14, 09:23 PM
P: 356
To sharpen a picture, look at the "unsharp mask" plugin for paint.net. It's name is deceptive. It actually sharpens edges. It must be used judiciously because it is easy to overdo the effect. Done well, it is can be really improve a dull photo. You can actually see some of that effect in many professional photos and HDTV screen images.

jtbell
#4
Sep3-14, 10:16 PM
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How do I enhance low quality JPEG images?

Unfortunately, unsharp mask tends to increase the "graininess" of an image, i.e. "noise" in areas that are supposed to have a smooth texture. It works best for enhancing soft edges and making them look sharper.
zoobyshoe
#5
Sep3-14, 11:31 PM
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Andre knew of a good, free online photo editing program that had an excellent noise reduction filter. "Graininess" often means too much noise. Maybe he'll see this thread.
FactChecker
#6
Sep4-14, 04:17 AM
P: 356
Quote Quote by jtbell View Post
Unfortunately, unsharp mask tends to increase the "graininess" of an image, i.e. "noise" in areas that are supposed to have a smooth texture. It works best for enhancing soft edges and making them look sharper.
Good point. The OP mentions both low resolution and wanting to "sharpen" them. I would recommend that he find a friend with Photoshop and test a photo to see what will work. Then he can look for those capabilities in free software. I have seen photos where fractal techniques were used to add artificial detail that looked very realistic.
B0b-A
#7
Sep4-14, 04:41 AM
P: 74
"de-jpeg" blurs the edges of the jpeg blocks making them less conspicuous ...

https://www.topazlabs.com/dejpeg [30 day free trial ]
Attached Thumbnails
de-jpeg, before-after.jpg  
B0b-A
#8
Sep4-14, 05:00 AM
P: 74
Alternatively ''wavelet denoise'' plugin on GIMP , [GIMP and plugins are free] ...
Attached Thumbnails
''wavelet denoise'' plugin on GIMP.jpg  
Borek
#9
Sep4-14, 05:30 AM
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Just remember - the image may look better, but as Greg said in the very first answer - it won't have more information than there was in the compressed image. Changes will be only cosmetic, to appease the eye.

Actually in a way they will make the image worse - while it will look better, it will contain other artifacts, not as visible, but still degrading the information stored. You may try to take a picture of a newspaper with different sizes of text (ads, titles, plain text), and then to see which parts of the text can be still read after saving the image with different levels of compression and after applying different filters. My bet is that each additional operation will make the newspaper more difficult to read.
B0b-A
#10
Sep4-14, 06:57 AM
P: 74
Quote Quote by Borek View Post
... My bet is that each additional operation will make the newspaper more difficult to read.
If the brief is to sharpen blurred-text see "SmartDeblur" ...

Before


After

Now readable, but with plenty of artifacts.
Borek
#11
Sep4-14, 10:25 AM
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Interesting and impressive, but that's not exactly the same thing. If the blur is added in a "systematic" way the information is still in the picture - and it is possible to attempt to recover it. When the image was compressed with the lossy compression situation is different.
Incnis Mrsi
#12
Sep4-14, 12:53 PM
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P: 59
Quote Quote by Borek View Post
If the blur is added in a "systematic" way the information is still in the picture…
It’s me who should say about this. Not exactly as Borek claims because of rounding errors, but blurring an image in computer’s memory, especially if lossy compression is not applied, inflicts much less data loss than blurring due to physical effects in realistic conditions (such as out of the focus photograph).
FactChecker
#13
Sep4-14, 06:37 PM
P: 356
Quote Quote by Borek View Post
Interesting and impressive, but that's not exactly the same thing. If the blur is added in a "systematic" way the information is still in the picture - and it is possible to attempt to recover it. When the image was compressed with the lossy compression situation is different.
A lot of what makes a photograph look sharp is not the amount of information. I think that HDTV looks good even on a very large screen at a size to which I would hesitate to blow up a photograph. If you figure the photograph pixel count that HDTV is equivalent to, it is less than most cameras. Of course an extremely small pixel count will be hard to fix.
Borek
#14
Sep5-14, 02:25 AM
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Quote Quote by FactChecker View Post
A lot of what makes a photograph look sharp is not the amount of information.
Sure - but first, OP never stated what he wants (just an appeasing effect, or getting more information from the picture), second, my bet is OP is not aware of the distinction (so he can be wasting his time trying to do something that is impossible).
WallaceCox
#15
Sep7-14, 01:56 PM
P: 6
Hello, You can try this 6 steps from wikihow : http://www.wikihow.com/Improve-Jpeg-Image-Quality

Thanks


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