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RL wavelength spectrum
Posted by rj-schneider on November 15, 2020 at 8:40 pmWondering out loud here about the use of RL distances on dark red brick. Shots well within operating range of instrument.
There are other factors involved in RL shots, but I was hoping to learn some about the physics (if it applies) of light spectrums
and affects on RL distancing. Thank you
rover83 replied 3 years, 5 months ago 8 Members · 13 Replies- 13 Replies
RL?
Historic Boundaries and Conservation EffortsReflectorless?
Maybe RL=Red Laser.
Maybe it’s Ralph Lauren. Anyway, this is a good example of why non-standard abbreviations do not work.
Historic Boundaries and Conservation EffortsI’ve used Topcon, Leica, & Trimble…..one of them uses RL in their documentation. I just can’t remember which one at the moment and lack the time to go look.
Leica uses RL and Topcon uses N/P for reflectorless
The reflectivity of brick is pretty low to begin with. Found this site which has approximations of reflectivity of common building materials.
As you mentioned, there are other factors as well. In my experience, the most critical factor is angle of incidence. No matter how reflective that object is, if most of that beam isn’t going back to the instrument it won’t get a good return.
“…people will come to love their oppression, to adore the technologies that undo their capacities to think.” -Neil Postman@bill93 that may be true, but I can tell you from experience that shooting brick house corners at 30+ degrees off angle with a Trimble S6 does not give reliable results.
@rover83 Thank you, Sir.
I was able to shoot two sides of a 4’x4′ brick column from two separate traverse points, and the results are within 0.01′ of what the 25′ tape reads.
I think my head got lost in wondering if it were that an object that appears red, to our eyesight, is absorbing all the remaining wavelengths
in the light spectrum, and reflecting only the red, or if it were absorbing the red .. or ???? no clue here.
There’s been documentation that certain surfaces or colors don’t return good RL results. Thanks registereds.
I have a study Charlie Glover and Geometrics performed from (portion) high atop our building that centered on Leica’s laser, its reflectivity, and what happens when it reflects off a corner. I will see if I can find it and if it not proprietary, will upload same. If I cannot find it, maybe Doug (if he is reading) or someone else can and will.
Depending on the type of instrument, as well as its age, certain EDMs will perform better than others.
Trimble used to have two options available for the S6, one using time-of-flight and the other using phase-shift. I believe the S7s are all TOF now…the signal processing has supposedly improved over the years as well, to the point where the TOF is pretty much neck-and-neck with phase shift, plus has the benefit of longer range.
I seem to remember reading a paper discussing Leica’s EDM and ATR capabilities that indicated Leica uses some combination of phase analysis and TOF to get results. No idea how they do that…but Leica still seems to have an edge over Trimble in the reflectorless department.
“…people will come to love their oppression, to adore the technologies that undo their capacities to think.” -Neil Postman
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