VFX I

3.6 Stitching


In this tutorial, we will stitch the panorama with Autopano Giga. We will start with the normally exposed images without using all brackets. We will then create a QuickTime VR with pano2VR, which allows us to pan around in the panorama and take a closer look at the stitching quality

Organizing Files

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Align Brackets

Before importing images, sort them first

Use icon view and adjust window size so all brackets are nicely aligning

Check that everything you need is there, move outtakes away

Here are 5 brackets for

3x horizontal

1x up

1x down (With tripod in the center, should be 2 shots actually)

2x extra floor (With photographer’s legs)

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Folders

I’ve organized my files into folders: 1stop is the normal exposure copied over from brackets folder, floor-extra are additional floor outtakes


Autopano Settings

These are global settings affecting all coming stitches

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Open Settings

Preferences on Mac

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Select Detection page
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Set Global Settings

Use relative path: Enable

Auto color correction: Off


Stitch One Bracket First

To test which floor shots work and which don’t, it’s easier to start without all brackets but with 1 exposure set only

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Import and Detect

Import normal exposure set, without all brackets

Select Images to import

Detect to auto stitch panorama

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Stitch Rough Blend

What you see is just a rough blend. The Preview is in the Edit View

Also, check Color Correction and RMS


Preview and Edit View

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RMS Error value

First, check the RMS error value
Green flag, good

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Preview

Hit Preview – Looking much better

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Horizon

If horizon is not leveled, use Move Tool, grab picture and move to adjust

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Layer

If result shows unwanted artifacts, i.e. from floor handheld shots, visit the Layer View

Try several combinations of floor shots by disabling and enabling


Save and Render

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Save first, then Render

Save stitch setup with meaningful name

Render output will use that name

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Render Settings

 

Output Size: Set to 50% to reduce render times, not for final render

Blending Preset: Anti-Ghost

Format: JPEG or TIFF (Both support EXIF)

Exported Data: Panorama for the first test
Layers for the final bracket render

Output: Strongly recommended to save stitch setup first. Render output will use the setup name – as it always should be

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Output

You’ve stitched your equirectangular panorama

Congrats! Let’s convert to QuickTimeVR and pan around, and check the stitching quality


QuickTime VR

I’m using Pano2VR to convert the panorama image to a QuickTimeVR

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Create QuickTime

1. Select Input

2. Confirm image ratio is exactly 2:1. One missing pixel and QuickTime won’t work. Fix in Photoshop if needed

3. Save Pano2VR setup

4. Add QuickTime, deselect HTML in QuickTime window

Enjoy the QuickTimeVR and pan around to check for stitching errors

If you’re happy with the overall stitching quality, move on to Stitching the Brackets

If quality is not good and detailed high quality is needed for close-up reflections, jump to section Improving Stitch


Stitching Brackets

Stitching the normal exposure went well, let’s move on to stitching all brackets

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Import

Repeat the Import, now with all brackets

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Create Stacks

Select all images > right-click > Create stacks by N…

This will group exposures by shots

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Number of pictures per stack:
Number of exposures / brackets

Index of main picture:
My normal exposure is image 3

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Rough Blend

Hit Detect and wait for the rough blend
Preview is in Edit View

Also check Color Correction is None

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RMS Error value

First check is RMS error value
Green flag, excellent

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Preview and Horizon

Preview the stitch

If horizon is not leveled, use Move Tool, grab picture and move to adjust

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Layer View

If result shows unwanted artifacts, i.e. from floor handheld shots, visit Layer View

Try several combinations of floor shots by disabling and enabling all exposures of one shot

Group by Stacks will sort by exposure, but still requires you to open all groups

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Render Settings

Save stitch first, then render

 

Output Size: Set to 100% for final render

Blending Preset: Anti-Ghost

Format: JPEG or TIFF (Both support EXIF)

Exported Data: Layers for final bracket render

Output: Strongly recommended to save stitch setup first. Render output will use the setup name – as it always should be

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Output

We’ve rendered one Layer for each exposure


Improving Stitch

There are several ways to improve the stitch quality. We can dig deeper by adding manual control points with the Control Point Editor or even masking out regions with the Mask Tool

 

Optimization

Older Autopano versions have manual optimization settings

Edit view > Control Points Editor > Optimization Settings > Optimizer Stages: Lower the value of Keep only control points below this error

Then still in Control Points Editor hit Optimize

Leave Control Points Editor and check in General Information if Global RMS has improved

 

Control Point Editor

We can add control point pairs for 2 overlapping images if we feel that the automatic detection missed obvious and important features. This can become a time-consuming effort, hopefully, you won’t need it. I would rather re-shoot with more images if possible

Edit view > Control Points Editor

Select an image pair in the Current Link View. The idea is to find a pair which has too few common control points and too high RMS error values


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Control Points Editor

Use Add auto control points to drag shape over same features in image pair

Use Add manual control points to position a cross-hair over same features in image pair

Use Quick Optimization to evaluate new control points

Finally, use Optimize to recalculate and check if RMS improved

Video tutorial Control Points Editor from Kolor on YouTube