laser lidar for grass height measure

[mopi7120]

Good morning,
I'm looking for a laser lidar to measure the grass height.
This is a farm project, I need a sensor on a drone to measure the grass height.
I would like to know if you rekon that laser lidar would be the best solution ?
If yes which one do you advise me ?
I need one that could get ground level AND the top of the grass.
Else, if you rekon it won't work, one for the ground level and i will use an ultrasonic sensor for the top of the grass.

Thank you very much for your help,
Clement.

 

[solentlife]

As per my previous answer :

When we tried to use Ultra Sonic and Laser rangers for measuring freeboard of ships (thats the distance from deckline to surface of water) - we had serious trouble. That's at relatively short distance of 20m and less ...

Any movement of the water surface - even a tiny ripple threw the unit of and ERROR shown.

With grass - I would imagine even worse as its not dense enough to create the reflected beam to measure. Lets be honest - the VPS on the Pro / Adv models has enough trouble with grass !

If you do find a unit to work ... we'd be interested. I assume you are going to be far higher than 20m ? As the range increases - the problem increases exponentially.

Nigel

 

[Richard R]

Good morning,
I'm looking for a laser lidar to measure the grass height.
This is a farm project, I need a sensor on a drone to measure the grass height.
I would like to know if you rekon that laser lidar would be the best solution ?
If yes which one do you advise me ?
I need one that could get ground level AND the top of the grass.
Else, if you rekon it won't work, one for the ground level and i will use an ultrasonic sensor for the top of the grass.

Thank you very much for your help,
Clement.

After spending 30 years building Lidar for the DOD, pretty confident when I tell you you're not gong to do it wth anything that might fit on a small UAS. The best we developed had a range resolution of around 1 foot and weighed about 50 lbs. it did a great job distinguishing between the ground and the top of trees, but grass just doesn't produce a return signal that would allow you to break out returns from the grass and the ground below it.

 

[mopi7120]

Ok, even if I fly maximum 5m of the ground ?
Do you rekon I'll get the return signal of the ground or the top of the grass ?
Do you have an other idea how I could measure the grass height using an other technology?
Thank you very much for your help !

 

[Steve7777]

Ok, even if I fly maximum 5m of the ground ?
Do you rekon I'll get the return signal of the ground or the top of the grass ?
Do you have an other idea how I could measure the grass height using an other technology?
Thank you very much for your help !

You might try investigating programs which can provide measurements from photographs. Essentially you extrapolate to get measurements after having established a base target of known dimensions. There was one on the market years ago which was called i-photomeasure/u-photomeasure, but I don't know if it's still being developed. There may now be others available.