M2P Panoramas curving straight lines?

[PC1134]

Are you using a very wideangle lens for panorama shooting with the dslr?

The wider the lens and the wider the panorama, the more complications you introduce. It is possible to do it right but you can't just drop the images into Lightroom and tell it to stitch.
There are many different stitching projections.
Start by trying some different projections.
Here are a couple of examples:

So this issue is with my Mavic 2 Pro drone which has a fixed wide angle lens.

 

[PC1134]

I put my M2P up in the air high enough to get the composition I need. I use an iPad and grid for my monitor.
Shoot at least 5 or 6 shots from left to right using the yaw stick, and I overlap the images about 30%.
Save all images as RAW files.
Upload the SD card to my desk top.
Open the images in Photoshop CC 2020 and then in Adobe Camera RAW. (ACR).
Right click on one of the images,
click on select all,
right click on one image again
MERGE TO PANORAMA.
Follow the prompts to complete the image.
Then you can adjust the image parameters e.g.: shadows, brightness, etc). Here is a recent image down with this technique.

So this is what I had suggested, instead of allowing the drone to do an automatic pano, you are suggesting yawing the pano in a horizontal plane, overlapping the images and the stitching those results. I'm going to give this a try.

 

[PC1134]

This idea is in conflict with very basic rule for successful panoramic stitch. Only PTGui Pro software version is offering some form of parallax correction, but I never had the need for such. Aerial panorama differs from tripod ones in radical way since the camera is pointing usually well below 0 deg. Therefore the bottom part of stitched image will always exhibit more distortion, most of the time to the point of being useless and cropped out. For truly high resolution, realistic panorama you'll have to employ a drone and camera with equivalent of 50mm full frame lens, i.e. Inspire 2 with X5S gimbal and 25mm lens.

Oh crap!!! Not buying one of those! Wonder if the Mavic 2 Zoom at 48mm would do this?
I also might give Ptgui Pro a try.

 

[Dobmatt]

So this is what I had suggested, instead of allowing the drone to do an automatic pano, you are suggesting yawing the pano in a horizontal plane, overlapping the images and the stitching those results. I'm going to give this a try.

No, this is not what you had suggested. Your idea is to move the drone horizontally, not to yaw. Manual shooting will not deliver any benefits.

 

[Dobmatt]

Oh crap!!! Not buying one of those! Wonder if the Mavic 2 Zoom at 48mm would do this?
I also might give Ptgui Pro a try.

Mavic 2 Zoom camera may do the trick indeed, but the image quality of Pro is superior. I highly recommend experiments with 3x3 option and cropping.

 

[Dobmatt]

After further investigation of the issue, here's my conclusion:

I have no idea why DJI decided to employ wrong projection to a in-the-app baked horizontal pano JPEG render. Moreover, I have no idea why the sequence is absurdly wide, containing 21 images (3 rows x 7 columns). No stitching software is able to maintain acceptable deformation on the most extreme ends of M2P panorama this wide, which must be cropped out no matter what projection type is used. Therefore left and rightmost columns of recorded stills should be discarded as useless, assuming an attempt to create hand made stitch in dedicated software of your choice. Here's a screenshot of PTGui stitch with equirectangular projection type used by DJI algorithm. Bowed top and bottom are obvious:



The same stitch projected in rectilinear mode maintains straight lines, still the most left and right sides are badly deformed and destined for crop out in post:



Both renders, trimmed and edited in Photoshop ...





Bottom line: horizontal panorama made by DJI will be always bowed. Experiments with different projections in dedicated stitching software may deliver much more palatable results. Good news is that cropped image should reclaim most valuable portion of the stitch with approx. 200 MP size. This will produce detailed 100 cm x 50 cm printout at 300 dpi resolution ...

 

[DaveK-OR]

A rather long time ago, I was doing panos with the equivalent of a 18-36 mm (give-or-take) full-frame lens at the widest zoom. I tried a number of pano stitching programs, and PTGUI was the one that I could ALWAYS depend on to compensate for nearly all of the wide-angle distortion. There may be more expensive programs that do stitching a little better, but PTGUI was always dependable, and you were able to choose some rather unique outputs (like mapping a full-spherical pano onto the six sides of a cube).

Since it seems that program is still around, I'd recommend giving it a hard look for doing your stitching.

 

[Dobmatt]

A rather long time ago, I was doing panos with the equivalent of a 18-36 mm (give-or-take) full-frame lens at the widest zoom. I tried a number of pano stitching programs, and PTGUI was the one that I could ALWAYS depend on to compensate for nearly all of the wide-angle distortion. There may be more expensive programs that do stitching a little better, but PTGUI was always dependable, and you were able to choose some rather unique outputs (like mapping a full-spherical pano onto the six sides of a cube).

Since it seems that program is still around, I'd recommend giving it a hard look for doing your stitching.

Undoubtedly. PTGui is the leader and progressing as for now ...

 

[DaveK-OR]

Another tool you might want to look at for panos or high-res stitched mosaics is PTAssembler. The interface may be a little clunky, but it is rather a powerful stitching tool and worth the time learning to use it. You can download it without cost, and only have to deal with the watermarks that are embedded in your output... If you like the program, the cost is pretty modest for what it can do (under $50, at this point).

 

[Paul2660]

The lens 35mm equivalent is around 10mm. And 10mm lens with a retrofocus design will give a similar result when the lens is used in a landscape projection. Albeit the DJI lens on the MP2 has considerable distortion already so as you stitch the issue will get worse.

Best solution as what the Mavic Pro Platinum offered, the ability to rotate the lens 90 degrees to allow you to take a manual pano. Stitching multiple portrait orientation images into a single landscape orientation image.

Next best solution would be a lens with a 50mm 35mm equivalent which would have much less distortion.

I shoot almost all my work from the MP2 in a pano. Manually. Then stitch it in one of the various software solutions already mentioned. You will get good results with a three shot pano with about 20 percent overlap. The more the lens is pointed either down or up the more the distortion will increase.

The main problem with just using 3 horizontal shots is it tend to cut off the sky. So to get the best image you would want to consider a second series aimed upward to grab more sky. Manually it’s a lot of work but results can be impressive.

Paul C

 

[Meta4]

The lens 35mm equivalent is around 10mm.

10mm ??
The specs show: 35 mm Format Equivalent = 28 mm

 

[Paul2660]

I stand corrected. However even the 28mm has plenty of distortion.
What I wrote will work.

DJI designed the drone for video.And for that job it does a good job. For panos the best results need work in software and manual capture.

Paul C

 

[Dobmatt]

The lens 35mm equivalent is around 10mm. And 10mm lens with a retrofocus design will give a similar result when the lens is used in a landscape projection. Albeit the DJI lens on the MP2 has considerable distortion already so as you stitch the issue will get worse.

Best solution as what the Mavic Pro Platinum offered, the ability to rotate the lens 90 degrees to allow you to take a manual pano. Stitching multiple portrait orientation images into a single landscape orientation image.

Next best solution would be a lens with a 50mm 35mm equivalent which would have much less distortion.

I shoot almost all my work from the MP2 in a pano. Manually. Then stitch it in one of the various software solutions already mentioned. You will get good results with a three shot pano with about 20 percent overlap. The more the lens is pointed either down or up the more the distortion will increase.

The main problem with just using 3 horizontal shots is it tend to cut off the sky. So to get the best image you would want to consider a second series aimed upward to grab more sky. Manually it’s a lot of work but results can be impressive.

Paul C

With all do respect, Paul, manual panorama shooting with Mavic 2 Pro has absolutely no advantage as opposed to auto, DJI programmed pano mode. The drone with "stiffened" camera is performing exactly the same yawing movements in both situations, only much more efficiently in auto. I totally agree that 3 horizontally spaced and properly overlapped images with this lens will produce most palatable results, but 3x3 auto approach is flawlessly and quickly executed, offering a plenty of stitched real estate to deal with and crop out unwanted parts in post.

 

[Paul2660]

If that works for you then sure it’s the right way to shoot. The auto mode for is pretty worthless as you can’t Bracket with it and the So in mixed light sunrise or sunset or similar you will have trouble with either blown highlights or way totally much noise in shadows. The auto is only creating a jpg image and for me leaves too much on the table in regards to image quality.

For sure I would love to have bracketing one pano mode as the drone has more precise control over the movements over doing this manually.

Paul C

 

[Dobmatt]

If that works for you then sure it’s the right way to shoot. The auto mode for is pretty worthless as you can’t Bracket with it and the So in mixed light sunrise or sunset or similar you will have trouble with either blown highlights or way totally much noise in shadows. The auto is only creating a jpg image and for me leaves too much on the table in regards to image quality.

For sure I would love to have bracketing one pano mode as the drone has more precise control over the movements over doing this manually.

Paul C

Misunderstanding. I'm not talking about auto-generated JPG stitch, which is made with wrong type of projection anyway. I'm talking about automatic shooting of DNG sequence, which is stored in separate folder. I'm shooting 3 identical 3x3 sequences with different exposure settings to copy with shadow noise, if required. Never failed to deliver ...

 

[PC1134]

After further investigation of the issue, here's my conclusion:

I have no idea why DJI decided to employ wrong projection to a in-the-app baked horizontal pano JPEG render. Moreover, I have no idea why the sequence is absurdly wide, containing 21 images (3 rows x 7 columns). No stitching software is able to maintain acceptable deformation on the most extreme ends of M2P panorama this wide, which must be cropped out no matter what projection type is used. Therefore left and rightmost columns of recorded stills should be discarded as useless, assuming an attempt to create hand made stitch in dedicated software of your choice. Here's a screenshot of PTGui stitch with equirectangular projection type used by DJI algorithm. Bowed top and bottom are obvious:

View attachment 114174

The same stitch projected in rectilinear mode maintains straight lines, still the most left and right sides are badly deformed and destined for crop out in post:

View attachment 114173

Both renders, trimmed and edited in Photoshop ...

View attachment 114175

View attachment 114176

Bottom line: horizontal panorama made by DJI will be always bowed. Experiments with different projections in dedicated stitching software may deliver much more palatable results. Good news is that cropped image should reclaim most valuable portion of the stitch with approx. 200 MP size. This will produce detailed 100 cm x 50 cm printout at 300 dpi resolution ...

Hi Dobmatt, I did try PTGui before, but not on rectiliniar mode. I've just re-done them in this mode, and 'Voila!!!' It has worked and fixed my curving lines. I'm so delighted and grateful. Now, either have to use the eraser rubber in Ps to remove all the PTgui stickers in the trial version, or dig deep and buy it !!!! I think the latter. Thank you so much, I really do appreciate your kind help here!!!

 

[Dobmatt]

Hi Dobmatt, I did try PTGui before, but not on rectiliniar mode. I've just re-done them in this mode, and 'Voila!!!' It has worked and fixed my curving lines. I'm so delighted and grateful. Now, either have to use the eraser rubber in Ps to remove all the PTgui stickers in the trial version, or dig deep and buy it !!!! I think the latter. Thank you so much, I really do appreciate your kind help here!!!

Glad to be useful ...

 

[PC1134]

Glad to be useful ...

The only comment I make, is the colours it produces are quite flat compared to Lightroom and the skies tend to be a bit patchy, whereas Lr renders them really well. I edit it in Photoshop and can tart it up there better, but it's still not as nice a result as creating the pano in Lr and then doing final edit in Ps. But, it does a better result in keeping the lines straight and giving you chance to stretch and move things around.

 

[Paul2660]

You can pick a rectilinear in CC or LR also, and should always start with that, or "reposition" in CC. rectilinear in CC or LR is called "Perspective". It will render the same or close to the rectilinear in PTgui. Also the Auto mode in CC will almost always try to use the Perspective as it's first try.

The reposition option IMO is the best for a manual pano as if the images align you will have almost no areas to crop out.

If you are forced to the Cylindrical or Spherical modes to get a good solution in CC, then you can always select the entire image and warp out a lot of the issues, watching to make sure you don't distort something in the process. If you over warp, you can develop softness in parts of the file.

Last time I checked LR still has problems with imported tif when it creates a pano with them, as it for some reason pushes shadows and highlights and tends to blow them out. I do not use LR for Mavic Pro 2 raw conversion since I don't like the conversion and fact that LR or CC don't have a dedicated color profile for the files. But I will usually try LR first for a pano since it has the "Boundary Warp" option which IMO works very well and does not seem to cause a loss of image details.

Paul C

 

[Dobmatt]

The only comment I make, is the colours it produces are quite flat compared to Lightroom and the skies tend to be a bit patchy, whereas Lr renders them really well. I edit it in Photoshop and can tart it up there better, but it's still not as nice a result as creating the pano in Lr and then doing final edit in Ps. But, it does a better result in keeping the lines straight and giving you chance to stretch and move things around.

PTGui may employ a bit different recipe for blending and colour rendering, but I've found no problem whatsoever performing final grade of TIFF or JPEG stitch in Photoshop. Here, however, I will use Camera Raw Filter for this task.