It's happening now, the laws of physics are pushing the limits of what can be resolved with a 6mm videoscope. But wait, can't you just put a higher pixel count chip and get more resolution? No, you can't. Find out why companies like Olympus don't advertise the pixel count of their videoscopes and why you should be weary of advertisements of more pixels when you're looking for the best image. What kind of things truly go into producing high quality and high resolution videoscope image. This presentation is about how optic companies optimize physics concepts such as the lens diffraction, Rayleigh criterion, Airy disk, circle of confusion, MTF, and aberration correction in reference to performing a remote visual inspection. Further explained will be the actual requirements to use higher density CCD chips as well as the reasons why more pixels do not translate simply to a better image. The factor of light emission using laser diode technology, even dispersion, optimized optics and finally the advanced processing and algorithms that enhance that goes into capturing and generating the highest resolution image for industrial videoscope. Find out what goes into getting an inspector the very best chance at detecting issues, and seeing them clearly to make confident decisions.

1. Approaching a Videoscope’s Highest
Physics-Limited Resolution to Improve RVI
What goes into optimizing inspection resolution to increase probability of detection?
Frank Lafleur
Long Beach, CA — October 25th, 2016

2. Premise of RVI
 Acquire an image that is not possible to see with the human eye on its own.
 Need to see as much of the area in front of the remote viewing device as
possible and have the entire view in focus and with ideal light and color.
 Better technology alone does not achieve these two key factors, but design and
assembly skill maximize physics.
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3. Main Components of a Remote Video Image
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Physics & skill Technology

4. Physics Challenges Acting Against Achieving a Good RVI Image
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Diameter
Flexibility
& access
requirements
Portability
Durability

5. The Physics of Maximizing Resolution
 In reference to optics
– Aberrations and distortions
 In reference to aperture
– Light
– Diffraction
– Circle of confusion
 In reference to camera chip
– Size of chip
– Size of pixels
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6. Optics — Monochromatic Optical Aberrations
 Spherical aberration
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7. Optics — Monochromatic Optical Aberrations
 Astigmatism
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8. Optics — Monochromatic Optical Aberrations
 Distortion
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9. Optics — Monochromatic Optical Aberrations
 Modulation transfer function (MTF) and line pair capability
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10. Optics — Chromatic Optical Aberrations
 Chromatic aberrations: axial and lateral
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11. Aperture — Effects of Aperture on Image
 Light availability and dispersion
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12. Aperture — Effects of Aperture on Image
 Diffraction and airy disc
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13. Aperture — Effects of Aperture on Image
 Depth of field and circle of confusion
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14. Chip — Physics Considerations of Camera Chip
 Size of chip
– It must typically fit inside a 4 mm or 6 mm distal end. If that isn’t a limitation,
the CCD size and aperture size are also not limited.
 Size of pixels
– Pixel sizes from 1.9 µm to 5.6 µm are common. At this size, the precision of
the required optic system is critical. Based on this, as pixel sizes approach
2.0 µm, diffraction patterns must be kept to 4–5 µm or they risk being
diffraction limited.
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15. Common Corrective Measures
 Lens materials
– The ability to use multiple materials to make a lens system opens many
possibilities.
– This type of system costs more and is more complex, including durability
considerations.
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16. Common Corrective Measures
 Stopping aperture
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Makes it darker; not
good for inspections.

17. Common Corrective Measures
 Offset aperture
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Longer distal end;
often not acceptable for
navigation/inspections.

18. Common Corrective Measures
 Lens systems
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Best solution, but costly
and requires greater
assembly skill.

19. Where are physics causing bottlenecks?
 Micro-optics manufacturing
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Greater chip density makes even the
smallest aberrations more obvious.

20. Where are physics causing bottlenecks?
 Diffraction limitation and aperture requirements
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Higher density chip will not correct
for diffraction limitation.

21. Conclusion and Advice
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• Be aware of the major physics factors:
• Micro manufacturing and assembly
• Diffraction limitation for <=6 mm videoscopes
• Don’t be lead astray by inconsequential specifications that don’t translate to
image quality:
• Pixel count, lumens, pixel size
• Use MTF and line pairs as guides, but color reproduction can only really
be evaluated in person.
• See videoscopes for yourself, on your application.