Pursuit Camera on Curved Monitors

Many sites including LinusTechTips, RTINGS, TomsHardware, and others use the free Blur Busters pursuit camera invention. Now also avaialble as a rail-less smartphone wave, too!
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Pursuit Camera on Curved Monitors

Post by Chief Blur Buster » 24 Jun 2020, 12:30

Support question recently answered to a reviewer who asked.
I decided to publicly post an answer to publicize pursuit camera knowledge for curved monitors.

Sync Track = Temporal test pattern = that horizontal ladder visible at www.testufo.com/ghosting

Pursuit Camera on Curved Monitors

Regular Pursuit Camera Is Fine, Including Camera Rails
Curve radius of curved actually produces error margins that are well below typical camera tracking error margins, so don't worry about curvature.
Rail-Based Method (Professional Reviewer Technique) (classic method)
Handwave Smartphone (Video Pursuit + Freezeframe Selection)
Are Handwaves Stupid? (Why Handwave Puruits Can Be Valid Science)

Monitor Curvature Won't Affect Sync Track Error Margins Meaningfully, Even For Straight Camera Rails
Most review sites use a photo crop of a pursuit camera test, covering only a few inches or few centimeters of monitor surface. The curvature over that tiny crop is almost equivalent to a flat monitor.

For handwaves the slight curvature might amplify hand rotation issue or parallelogramming issue of an oblique-angle pursuit photo. As long as the Sync Track has correct error margins (preferably subpixel), geometric corrections are acceptable for reviewer image presentation. It can be fixed via rotation/keystone correction. This is already as-seen by human eye, like viewing a monitor from an oblique angle, but all the WYSIWYG ghosting/blurs are still there, in the captured image.

For reviewer-image presentation to public, minor geometric corrections to pursuit camera photography is acceptable (crop, position, rotation, parallogram correction, keystone correction, bow correction, fisheye correction, etc) to help align them with standard pursuit imagery on the rest of your reviewer website.

Geometric-corrections can help align multiple separate pursuits to create interesting pursuit-versus-pursuit animations like this one.

Scientist Point Of View On Error Margins Of Monitor Curvature In Pursuit Camera
Now, researchers who read the scientific conference paper (peer reviewed, co-authored by me). Researchers who want to avoid geometric corrections, and map pursuits to oscilloscope graphs (GtG plot along a horizontal axis) -- with ultra-high-resolution cameras that want require tighter tolerances (e.g. Say, even as tiny as 1/100th pixelwidth error margin of ultra-accurate pursuit photography). Those may prefer to only use screen-centre zooms if using a straight camera rail. In our experience, straight rails have still generally created accuracy more cheaply (even with curved monitors) than rotating-camera setups, as real-world humans generally won't notice 1/100th pixelwidth artifacts (micrometers).

Alternatively, mathematics (algebra/calculus) can be theoretically curvature-compensate the horizontal linearity of a resulting pursuit photograph. However, lens distortions (fisheye) actually are a far bigger scientific error margin to the linearity of a photo along a vector along the plane of the resulting photograph.

My post is targeted to monitor reviewers who tend to be happy with approximately 0.1 to 0.5 pixelwidth tracking error margin for pursuit camera. For this, monitor curvature is not a meaningful error margin for straight camera rails. For showing WYSIWYG motion blur artifacts to the end user, these subpixel error margins tend to not matter.

Camera Depth of Focus Issue Is The Main Error-Margin Gotcha To Compensate
That said, bigger issue is fixed-focus cameras with a large depth of focus. You can decrease your aperture (increase F stop) to reduce the depth-field defocussing problem. Typical pursuit camera distance is usually same as human viewing distance for best emulation of a human viewing (you can use a slight amount of optical zoom if necessary, and/or simply use sheer megapixels and crop). Most cameras will not have focus problems in the focus depth range of a curved monitor.

Now, if you had a burst-shoot or video pursuit setup, and you were worried about distortions, you can prioritize the captures of the center of the pursuit.  Even so, good photos / freezeframes at left edge or right edge (even on a curved monitor) is better than screen centre.

In other words, "Trust the Sync Track".
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