This PN should be imaged with larger scopes than mine, but I thought it would be an exercise for Topaz AI processing, so for those of you using this software, here are some manipulations to consider:

In PixInsight you can get some of the structure by using HDRMT (here I used levels 2 and 3) since the whole image is only 22" x15" which at my image scale is less than 20 pixels across.

I then used Topaz Denoise to denoise the background, but that blurred the details from the HDRMT.

I then used Topaz Sharpen on the image to further sharpen the core.

I then loaded both as layers into Photoshop (File, Scripts, Load Stack with the clean background on top (above).

I then used the brush tool in black to remove the blurred core from the top layer.

I could not get Topax Sharpen to work as part of Denoise but had to use them separately.

Now this is not a great image, but for those of us working on the AI issues, it may stimulate discussion.... BTW, this detail is real I think, not pumped up noise, if you look at the Hubble images.  I wanted to write down what I did in case I have to go back also. 

From Wikipedia:

The Little Gem Nebula or NGC 6818 is a planetary nebula located in the constellation of Sagittarius. It has magnitude 10 and oval diameter of 15 to 22 arcseconds with a 15th magnitude central star.It was discovered by William Herschel in 1787.NGC 6818 is located in the constellation of Sagittarius (The Archer), roughly 6000 light-years away from Earth. The glow of the cloud is just over half a light-year across.When stars like the Sun are near end of life, they send their outer layers into space to create glowing clouds of gas, a planetary nebulae. This ejection of mass is uneven, and planetary nebulae can have complex shapes. NGC 6818 shows knotty filament-like structures and distinct layers of material, with a bright and enclosed central bubble surrounded by a larger, more diffuse cloud.Scientists believe that the stellar wind from the central star propels the outflowing material, forming the elongated shape of NGC 6818. As this stellar wind moves through the slower-moving cloud it creates particularly bright spots in the bubble's outer layers.[2]