Pat Traynor
Posts: 110
Location: Boston, United States
Registered: 4 Oct 2007
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Need to improve my sharpness
Posted: 23 Jun 2012 at 12:36 GMT
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I take some recreational panoramas, but for the most part, I'm doing them to create website virtual tours for real estate and property management. I'm not completely happy with my results. People say they're stunned by the sharpness, but since I've been hanging around here, I guess I have a higher standard that I'd like to live up to. Thing is, I don't have bottomless pockets, and I can't afford to drop five figures on improvements.
I've got an old Nikon D50 (6Mp) and a new Samyang 8mm. My process is to run the images through ptgui, then some minor adjustments in photoshop, and on to pano2vr to make the flash panorama.
I take one zenith and four pointed slightly down. I limit the downward view in pano2vr to block the tripod.
Ptgui creates a pano image over 7k wide. I would *think* this is plenty to make a sharp final product. I'm very close to buying a 16Mp Nikon D5100. Would this have a significant effect on the sharpness?
I've tried futzing with the settings in pano2vr, but I don't see a remarkable difference setting the image quality at 90 and the cube face at 2500, as opposed to a quality of 50, and cube face 1500. But the file size changes from 8k to 1.2k. This IS substantial when you're dealing with customers having a variety of connection speeds.
I'm almost certain that I'll be buying the D5100 regardless, but I'm curious if I'll be seeing a serious improvement in sharpness. Since I've already got what seems to me as a fairly high overall resolution on the final panorama, it almost seems like buying five hamburgers for lunch when you only have an appetite for one.
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DenisSS
Posts: 1307
Location: Nigeria
Registered: 2 Sep 2010
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Re: Need to improve my sharpness
Posted: 23 Jun 2012 at 13:21 GMT
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It depends on what sort of size file you want. You might also be looking at your panos on a larger monitor, which will always seem problemmatic for you, but is something that others might not notice so much.
When I use Pano2vr, I use the Blackman interpolator, which I think gives the sharpest setting. However, bear in mind that your tile size will affect sharpness considerably.
In Europe, we have quite fast internet speeds and it is not a problem uploading a panorama of 4-5 MB in size. When I log on to an American server, which I sometimes do, I am often impressed with how fast they are, although I also believe that in the sticks, there are often people using dial-up connections, still, and I suppose this is something you need to think about.
Remember also that the sharpness of your panoramas will also affect the size.
When I have produced panoramas for my pet project, roros360.com, I have worked with the idea that the optimum file size of 4,5 MB is a good compromise between quality and accessibility. This is using a tile size of 1900 pixels - others will tell you that it should be the equirectangular´s width divided by pi, but I am not too convinced by that. Usually, I can get by with a quality setting of somewhere between 70 and 80%, but with Pano2vr, you can also adjust the quality for each individual tile, which is useful, since nearby objects, such as the ground and perhaps a wall (?) can be reduced, leaving a little leeway for altering the size of those tiles where banding occurs or where more detail is needed.
As for sharpening the indivudual equis, there are a couple of things that I do. The first is sharpening the initial images, which DXO, which I use for converting from RAW to Tiff, does as a default at 25%. Useful, and something you should consider doing with the initial images, even if you can´t use DXO (which includes you, since your lens is not supported), since I think that will provide a better stitch.
When the assembled image is ready for sharpening, then you could use either the unsharp mask in Photoshop (given that I have already sharpened images, I use a setting of 100% at 0,4 pixels with a threshold of 0), or you could try experimenting with a high pass filter. I often use that now, with a pixel width of 1 and, given the subject matter, making the overlay setting "vivid light", which saves making a luminosity mask.
I hope all this helps a little.
Jon
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John Houghton
Posts: 3710
Location: Hitchin, United Kingdom
Registered: 17 Jan 2005
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Re: Need to improve my sharpness
Posted: 23 Jun 2012 at 16:57 GMT
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Tactus 360 said: When I use Pano2vr, I use the Blackman interpolator, which I think gives the sharpest setting.
Jon is right to draw attention to the importance of the interpolator setting. I don't know if it is still the case with the latest versions of Pano2VR, but it used to be that the interpolator selected by default on the Settings page was Mitchell, which gives rather soft results. I tested all the available interpolators and found that the degree of blurring or sharpening varied quite a lot. I wanted an interpolator that did the least damage, i.e. neither blurring nor sharpening the image. One that did well in this respect was Lanczos3. Blackmann gives slightly soft results but is sharper than Mitchell.
The differences between these interpolators are not huge, but will naturally become more marked when images undergo multiple stages of remapping/warping. Comparison results may well depend on exactly what tests are performed, so it's wise to do your own tests and decide what works best for you.
John
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vrbali
Posts: 194
Location: Bali, Indonesia
Registered: 12 Feb 2010
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Re: Need to improve my sharpness
Posted: 24 Jun 2012 at 5:24 GMT
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2.5x the resolution (from 6MP to 16 MP) will give considerably more space to play with sharpening while sizing down the image (if wanted). Also the sensor of the D5100 should have a clear advantage over the D50 (6 years difference).
I generally scale down my equirectangulars from +8000px to 6432px and sharpen on the final image (smart sharpen or Lab sharpen) and/or during resizing/resampling (read that resampling in steps of 10% gives best results and prevent moire). During raw processing or first stage of processing the 8k image in Photoshop, I do some noise reduction when needed.
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Pat Traynor
Posts: 110
Location: Boston, United States
Registered: 4 Oct 2007
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Re: Need to improve my sharpness
Posted: 24 Jun 2012 at 12:57 GMT
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Thanks for all the good info, folks!
I suspect that serious improvement is probably dependent on several changes. There's probably no silver bullet that's going to fix everything. But I've got a lot that I can play with now. I honestly had never modified the interpolator, so that's good to know.
And I *am* viewing my panos full screen on a 1920x1080 monitor, so I suppose I'm asking a lot of them. But this is the same monitor that I view your panoramas, and they all look pretty nice.
I suppose if I can keep tweaking my setup for performance, my customers will always be happy.
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DenisSS
Posts: 1307
Location: Nigeria
Registered: 2 Sep 2010
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Re: Need to improve my sharpness
Posted: 24 Jun 2012 at 14:10 GMT
updated: 24 Jun 2012 at 14:11 GMT
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John Houghton said: One that did well in this respect was Lanczos3. Blackmann gives slightly soft results but is sharper than Mitchell.
John
Agreed John, although I find that when using it with already sharpened images produces some heavily aliased results. I have noticed this particularly where there are a considerable number of uprights in an image. I don't get that with FCC and I am not sure whether I have dreamed this or not, but I find that when converting images to cube faces, using the same settings between Pano2vr and PTGui, the tiles are often a little crisper - although this then gives rise to issues of file size.
I would be interested to hear the findings of anyone else with regard to this.
Jon
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burake
Posts: 283
Location: Antalya, Turkey
Registered: 7 Jun 2012
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Re: Need to improve my sharpness
Posted: 26 Jun 2012 at 9:49 GMT
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Pat Traynor said:
ve tried futzing with the settings in pano2vr, but I don't see a remarkable difference setting the image quality at 90 and the cube face at 2500, as opposed to a quality of 50, and cube face 1500. But the file size changes from 8k to 1.2k. This IS substantial when you're dealing with customers having a variety of connection speeds.
I am very new in taking panoramic pictures and creating VR tours..I am using also pano 2VR and must find a way to decrease the file sizes as the internet speed in my country is low...I take pictures with a camera of 21.1 mp resolution...In ptgui I resize the output from appr. 14000x7000 px. to 10000x5000...When I go to pano 2 VR I get a cube face of 2500 px...When I accept the suggestion of pano2 vr of 685 px. and create the pano the sharpness is very bad...I thought of leaving the cube size as it is and making the quality lower (for example 60 instead of 90)...Will this alone reduce the file size?...Or does one have to decrease the size of the cube face too?
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DenisSS
Posts: 1307
Location: Nigeria
Registered: 2 Sep 2010
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Re: Need to improve my sharpness
Posted: 26 Jun 2012 at 14:52 GMT
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The Pano2vr setting of 685 px, I believe, is based on your monitor size/resolution. A cube face size of 2500 could be a little on the large size if Internet speeds are slow. You have to make an educated decision on what size monitor your target audience uses. For example, with my Røros project (roros360.com), I have made all the tile sizes 1900 px. These look fuzzy on my 23" monitor, but very crisp on my laptop. That is fine, since I think that more people will be looking at my images using laptops rather than desktops.
There are two things to bear in mind. The first is that you can adjust the quality of individual tiles in Pano2vr, so less detailed tiles, such as floor shots, which are generally nearer and therefore need less resolution, can have a lower quality than the actual focus of your panorama.
The second is that Pano2vr allows for multi-resolution images, which could solve your problem.
I think the yardstick when it comes to deciding on the quality setting is to reduce it, where necessary, to a point where banding in skies (for example) is about to occur. But whether it is better to have lesser quality and a larger tile or vice versa is still moot and will, ultimately, come down to your own preferences...
Jon
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vrbali
Posts: 194
Location: Bali, Indonesia
Registered: 12 Feb 2010
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Re: Need to improve my sharpness
Posted: 26 Jun 2012 at 15:15 GMT
updated: 26 Jun 2012 at 15:16 GMT
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Personally, I down-scale most of my final equirectangular images to 6432px and make the cube faces 2048px. As I shoot with Sigma 8mm on D300 (12MP) I get "only" between 8000 and 9000 pixels after stitching.
Like Jon said, it is just a personal preference and there is no rule for it. If you want to show the best quality on large monitors, download times should be a second thought (as with gigapixel panos).
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Smooth
Posts: 4013
Location: Mount Panorama, Australia
Registered: 21 Jul 2004
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Re: Need to improve my sharpness
Posted: 26 Jun 2012 at 16:27 GMT
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Tactus 360 said: The Pano2vr setting of 685 px, I believe, is based on your monitor size/resolution.
Any quoted/suggested size (optimal) from Pano2VR is based on the viewer window size (height) selected with the GUI. Change the height in the GUI and watch the "optimal" change with it.
So if you know the maximum or "target" screen resolution you wish to cater for, simple enter this as the "height" and it will let you know the optimal tile size based on Pi.
All that said: Do not permanently change the window height to create your .swf. Use it as a tool.
2048 x Pi = 6434px equirectangular 2:1 panorama image.
Regards, Smooth 
www.omnipix.com.au
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DenisSS
Posts: 1307
Location: Nigeria
Registered: 2 Sep 2010
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Re: Need to improve my sharpness
Posted: 26 Jun 2012 at 17:20 GMT
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Hi Smooth!
I stand corrected! However, and this is something I have wondered for a while, does the pi division have any real positive effect and why?
Jon
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burake
Posts: 283
Location: Antalya, Turkey
Registered: 7 Jun 2012
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Re: Need to improve my sharpness
Posted: 27 Jun 2012 at 5:46 GMT
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Thank you all very much for these useful inputs...Jon what exactly do you mean by
Tactus 360 said: The first is that you can adjust the quality of individual tiles in Pano2vr, so less detailed tiles, such as floor shots, which are generally nearer and therefore need less resolution, can have a lower quality than the actual focus of your panorama.
?
Is it about the subwindow "sub tiles" where you can choose values like 1,2,3 or more in the window "Tile settings"? Or do I have to push the button "tile quality" where a window opens with check boxes and make adjustments there?
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DenisSS
Posts: 1307
Location: Nigeria
Registered: 2 Sep 2010
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Re: Need to improve my sharpness
Posted: 27 Jun 2012 at 10:23 GMT
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When you choose Flash output, under the settings tab you will see Tile Quality . . .
Just open than and you can adjust that according to your needs.
Jon
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burake
Posts: 283
Location: Antalya, Turkey
Registered: 7 Jun 2012
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Re: Need to improve my sharpness
Posted: 27 Jun 2012 at 20:21 GMT
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Thank you very much Jon...
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