Debluring means reducing the blur in an image. It is generally done by sharpening. This in turn introduces noise. But, also denoising introduces blur. Doing both at the same time is not an easy task. What follows is a way of using reshade to help with this.
A noisy and blurry image of lizard skin
It is easily noticeable that when shrinking an image most of its (high frequency) noise and (low frequency) blur disappears. This observation is the main idea here. The image is downsized until both noise and blur are reduced to an acceptable level. Photoshop’s bicubic resize with “best for reduction” is used:
The task denoiseing and debluring is passed to the reshade algorithm. Here’s the upsized version starting from the above image (100 sharpen value):
Reshaded and upsize lizard skin
Some images look better than others when doing this, so varying the sharpen value and resize factor is very important. Try this out free with the online image resizer from reshade.com.
The following images are comparisons between upsizing the image in Photoshop and Reshade Photo Enlargement software, in this order from left to right. For strong edges notice the large difference in smoothness and reduction in artifacts:
Same quality can be seen even for very light contrast edges:
The blur that appears in the Photoshop enlarged image dissappears completely after reshading:
To see the original full image click here.
You can see below a resized version in Photoshop. To see the Reshade hover the mouse over the image. Please wait for it to load.
Reshade uses various sharpening and frequency shift interpolation methods. Photoshop uses the bicubic “best for enlargement” method.The following is the original image. A crop will be made and enlarged.
Crom from this image enlarged 16 times (1600%) in Photoshop
Do the same thing with reshading with different parameters:
Higher sizes for color patches (will be available on the site soon)
Lower sizes for patches (higher sharpen value)
Lower reshading strength, lower sharpening value (small patches)
All the images look about the same when downsized again. Shrinking them to just 25% gives the following results (now they are 4 times, 400%, as big as the original):
From left to right: photoshop, small patches, large pathes
Even greater zoom levels are possible:
