Re: [TANKS] Re: cheap laser distance range finder with USB output

[OdysseySlipways]

 
 
In a message dated 4/15/2013 10:01:45 P.M. Eastern Daylight Time,  
dwconn...@comcast.net writes:

Little  miniature windshield wipers and squirters  ?


na, need something like they have on race cars where the cover spins  to a 
clean spot
 
Chris

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RE: [TANKS] Re: cheap laser distance range finder with USB output

[Doug Conn]

Little miniature windshield wipers and squirters ?

 

From: rctankcombat@googlegroups.com [mailto:rctankcombat@googlegroups.com]
On Behalf Of Joe Sommer
Sent: Monday, April 15, 2013 9:27 PM
To: rctankcombat@googlegroups.com
Subject: Re: [TANKS] Re: cheap laser distance range finder with USB output

 


On Monday, April 15, 2013 4:27:24 PM UTC-4, TyngTech wrote:

"More sophisticated calibrations can handle image center offset, camera
misalignment and lens distortion."

Whats the calculation to handle paintball goo all over the lens?

 

Any tank that carries such a sophisticated fire control system

will need a cloaking device.  Anvilus is currently beta-testing

adaptive IR camouflage from BAE systems.

http://www.youtube.com/watch?v=Pftna34TbJU

 

Fred Simms, Director

Stealth, Targeting and Disinformation (STD)

 

 

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Re: [TANKS] Re: cheap laser distance range finder with USB output

[Joe Sommer]

On Monday, April 15, 2013 4:27:24 PM UTC-4, TyngTech wrote:
>
> "More sophisticated calibrations can handle image center offset, camera 
> misalignment and lens distortion."
> Whats the calculation to handle paintball goo all over the lens?
>
 
Any tank that carries such a sophisticated fire control system
will need a cloaking device.  Anvilus is currently beta-testing
adaptive IR camouflage from BAE systems.
http://www.youtube.com/watch?v=Pftna34TbJU
 
Fred Simms, Director
Stealth, Targeting and Disinformation (STD)
 
 

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Re: [TANKS] Re: cheap laser distance range finder with USB output

[TyngTech]

"More sophisticated calibrations can handle image center offset, camera 
misalignment and lens distortion."

Whats the calculation to handle paintball goo all over the lens?


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[TANKS] Re: New Business

[TyngTech]

You were speaking with Joe and Frank on track design huh?  Joe's still 
running his plastic conveyor tracks and Frank's stuff are copies of my 
designs.  Neither of them have fielded a viable active suspension as of yet.

When you want to get serious about small scale performance tracked 
propulsion, drop me a line   ;-)  There's more than just big 
tabs in a well executed track and suspension system.

For your motors, I'd stick with brushed for reliability starting in the 
250W range per motor (as a minimum).  If you have the room, the geared 
scooter motors are probably the cheapest option.  Look to the robot 
competition world for tested and reliable motor controllers.  Two good 
sites are Vex Robotics and AndyMark.

Steve


On Monday, April 15, 2013 9:39:13 AM UTC-4, lo...@fieldofarmortanks.com 
wrote:
>
> Steve,
> I had that discussion with Joe and Frank. This "oversize" guide tooth will 
> not be implemented with the "scale Panther", but we might look into it if 
> we explore a variation of these tracks for this hull that will support 
> "gamer's performances". HOWEVER, our "surprise tank" that we are working on 
> right now, in the background of the Panther/Jagdpanther hull, does include 
> oversize guide tooth, and it does not even look bad for people interested 
> in scale. The tracks are "smooth" which will allow rubber pads or just 
> using as is, so make donuts on grass and asphalt, without chewing on the 
> hardware.
>
> As soon as the track is addressed, we also need to address motors. It is 
> obvious that the motors we have are under-powered, which is OK for the 
> purpose of scale and simple RC. But if we want a "gamer's product", we need 
> to upscale the entire engine, from gears, motors and strength of the hull. 
> We are also looking at those options for the "surprise tank"... Please note 
> that we are interested in keeping costs under control. For this to work as 
> a business, we need to offer these tanks at affordable prices. I'm still 
> looking at an affordable "gear/engine" system to install. Any suggestion?
>
> Thanks for your answer! We will keep on posting our progress
> Loic
>
> On Sunday, April 14, 2013 7:19:13 AM UTC-6, TyngTech wrote:
>>
>> Loic wrote:
>>
>> "I'm contemplating a NEW product right now using our experience with the 
>> Panther hull, but more oriented toward the "gamers". The difficult question 
>> is always: THE TRACKS?"
>>
>> You hit the nail on the head.  Our scale combat models operate in a very 
>> un-scale environment.  They are asked to do things by their operators that 
>> a full size tank could never accomplish (in like field conditions) without 
>> throwing tracks all day long.  The answer to a reliable track design is big 
>> ass tracking tabs!  The taller the tabs, the less likely your going to 
>> throw a track (especially with active suspensions).  Even with a tensioned 
>> solid suspension, large tracking tabs are beneficial.  Joe's little Hetzer 
>> is a well designed and executed vehicle with a solid suspension, but he 
>> went with OTS plastic conveyor tracks that have tiny little tracking tabs. 
>>  As a consequence, Joe's gotten very good at track remounting in the middle 
>> of a battle.  With an active suspension, where the track runs loose around 
>> the wheels, tracking tabs are the only thing keeping things were they 
>> belong.
>>
>> In my designs, I build as large a tracking tab as possible with no regard 
>> to scale.  This is for performance sake as I'm a "gamer" where function 
>> comes first and scale a distant second.  This offers a quandary for you as 
>> your designs are most decidedly scale first.  To offer 
>> a performance suspension for gaming, are you willing to redesign the entire 
>> suspension?  We're talking not only larger tabs, but also the wheels and 
>> drive sprockets to accommodate them, maybe drop the segmented 
>> tracks altogether and go with a TTS belted design?  Is there a market to 
>> support the time, effort, and expense?  All good questions.
>>
>> Steve Tyng
>>
>>
>> 
>>
>

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Re: [TANKS] Re: cheap laser distance range finder with USB output

[Joe Sommer]

On Monday, April 15, 2013 10:37:18 AM UTC-4, RocketMan wrote:
>
> I guess if the calculations turned out to be wrong, a system liek 
> this could always be calibrated as you suggest.
>

If you assume that both cameras have the same focal length 
and resolution with minimal distortion, the following simplified 
equation should work for range significantly longer than horizontal 
camera separation.

r = range of target point from center between focal points of cameras 
[inch, ft, yd, m]
s = horizontal separation between focal points of cameras [inch, ft, yd, m]
d = horizontal distance between the image of the target point in right 
camera
 and the image of the target point in left camera [pixels]
f = focal length of cameras [pixels]

r = s * f / d

You must measure s accurately with a ruler or caliper.

For focal length in pixels units, you need to know focal length
of the lens [inch or mm units] and physical pixel spacing [inch 
or mm units].

Alternately, place the target point at several known range distances 
(r_1, r_2 ... r_n) and measure pixel separation distance for each (d_1, d_2 
... d_n).
.
f = sum( r_1*d_1 + r_2*d_2 + ... + r_n*d_n ) / (n*s)

More sophisticated calibrations can handle image center offset,
camera misalignment and lens distortion.

Joe

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Re: [TANKS] Re: cheap laser distance range finder with USB output

[dwconn404]

Hi Joe - 



>>  measure camera separation distance, 

Sure. My back of the envelope run through assumed a 6" separation. 



It seems like most of the other camera parameters you mention go into 
calculating the camera field of view. That value is published for many webcams. 
For example, the one I use has a 53 degree horizontal FOV. If you know those 
values couldn't you calculate distances ? It does ignore lens distoration, and 
the fish-eye lenses on some webcams would certainly screw things up. 



I guess if the calculations turned out to be wrong, a system liek this could 
always be calibrated as you suggest. 



    - Doug 





- Original Message -


From: "Joe Sommer"  
To: rctankcombat@googlegroups.com 
Sent: Monday, April 15, 2013 8:13:09 AM 
Subject: Re: [TANKS] Re: cheap laser distance range finder with USB output 


On Sunday, April 14, 2013 9:41:02 PM UTC-4, RocketMan wrote: 





Now, I guess I HAVE to see if it actually works… 

" I’m not even sure they’d need to pivot. It would be great not to use moving 
parts for this if possible. Cheap webcams now have a 1280 pixel horizontal 
resolution. If you separate two of those, facing straight ahead, by a known 
distance then you could calculate the physical distance based on the pixel 
separation of an image feature. 


Doug, 
  
Do not bother doing the trigonometry.  You will ultimately 
need to measure camera separation distance, focal length 
of each camera and lens distortion (barreling, pin cushion) 
which can be difficult to do accurately. 
  
I will dig out an algortihm that we used  in the bad old days of 
photogrammetry called the Direct Linear Transform (DLT).  See 
https://me363.byu.edu/sites/me363.byu.edu/files/userfiles/5/DLTNotes.pdf 
  
It inherently includes intrinsic camera paramters (focal length 
and lens distortion) and extrinsic camera parameters (focal 
point location and prinicipal axis orientation). 
  
To calibrate, you place a grid of points printed on a flat 
plate at several known ranges and measure pixel locations 
of the points.  The algoithm then calculates binomial coefficients 
that provide simple computation of global locations for 
a point that is visible to both cameras. 
  
We used it for photogrammetry in biomechanics of human 
movement for scientific analyses similalry to multicamera 
motion capture for computer generated images in movies 
(e.g. Golem in LOTR). 
  
Joe 
  

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[TANKS] Re: New Business

[l...@fieldofarmortanks.com]

Thanks for your suggestions Fred. Actually this is our exact direction. 
Modelers, RC, and gamers do not "eat at the same table"... (-;
As for "cute accessories", we are still going to offer our resin 
accessories, but they will be SCREWED to the tank, rather than superglued. 
Not sure if it will take a paintball?

Cheers,
Loic

On Sunday, April 14, 2013 9:58:11 AM UTC-6, Fred Thomson wrote:
>
> You could use the same suspension but have different drive sprockets, 
> idler, and road wheels by using 2060 attachment chain. This would 
> pretty much solve the "throwing a track" problem. You could also 
> design the track plates to have a more "authentic look" and you could 
> bundle the whole thing up as an "option" for an extra cost. Call it 
> the Combat Gaming Track Option, to go with the Paintball Combat Gun 
> Option. 
>  Actually, you could save yourself a ton of grief by simply making two 
> distinct tanks. One for modelers and one for gamers (I hate that 
> connotation, btw). Make your combat tank a little more spartan in add- 
> on (read breakable) details that modelers slavishly apply to their 
> creations. A paintball gun that has been dialed up to 240ft/sec or so, 
> makes short work of plastic headlamps, open hatches, and at point 
> blank range, has been known to remove an RC antenna block mount quite 
> cleanly. Also give your customer a stern lesson in Battery Care & 
> Maintenance. 
>
>  As Steve pointed out, we ask our toys to sometimes do the impossible. 
> I had 3/4" Grade 8 bolts as road wheel axles and I bent them. Not just 
> one but 4 out of 10. This was after bending 7/16, 1/2, 5/8 in the same 
> application. I broke the bottom of my hull by hitting a pointy rock 
> hidden in the grass, at full speed. 3/4", fiberglass reinforced, 
> marine grade mahogany plywood and it didn't survive. Full speed was 
> only 12kmph, pretty close to scale speed. Oh yeah, water-tight is a 
> good thing. You know your customers are going to abuse them, I mean 
> it's a tank. What fun is there in owning a tank if you cannot drive 
> it, run over things, and shoot stuff with it? I think, for me, hell 
> would be defined as having a 1/6th scale tank sitting on the shelf and 
> being too afraid to drive or battle it cuz it's too pretty. 
>
> Hey Steve, how many man-hours does it take to make a set of TTS 
> tracks? It took me a horribly long time, but I made lots of 
> mistakes. :-) 
>
> Just my 2 cents. :-) 
>
> Cheers, 
> Fred 
>

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[TANKS] Re: New Business

[l...@fieldofarmortanks.com]

Steve,
I had that discussion with Joe and Frank. This "oversize" guide tooth will 
not be implemented with the "scale Panther", but we might look into it if 
we explore a variation of these tracks for this hull that will support 
"gamer's performances". HOWEVER, our "surprise tank" that we are working on 
right now, in the background of the Panther/Jagdpanther hull, does include 
oversize guide tooth, and it does not even look bad for people interested 
in scale. The tracks are "smooth" which will allow rubber pads or just 
using as is, so make donuts on grass and asphalt, without chewing on the 
hardware.

As soon as the track is addressed, we also need to address motors. It is 
obvious that the motors we have are under-powered, which is OK for the 
purpose of scale and simple RC. But if we want a "gamer's product", we need 
to upscale the entire engine, from gears, motors and strength of the hull. 
We are also looking at those options for the "surprise tank"... Please note 
that we are interested in keeping costs under control. For this to work as 
a business, we need to offer these tanks at affordable prices. I'm still 
looking at an affordable "gear/engine" system to install. Any suggestion?

Thanks for your answer! We will keep on posting our progress
Loic

On Sunday, April 14, 2013 7:19:13 AM UTC-6, TyngTech wrote:
>
> Loic wrote:
>
> "I'm contemplating a NEW product right now using our experience with the 
> Panther hull, but more oriented toward the "gamers". The difficult question 
> is always: THE TRACKS?"
>
> You hit the nail on the head.  Our scale combat models operate in a very 
> un-scale environment.  They are asked to do things by their operators that 
> a full size tank could never accomplish (in like field conditions) without 
> throwing tracks all day long.  The answer to a reliable track design is big 
> ass tracking tabs!  The taller the tabs, the less likely your going to 
> throw a track (especially with active suspensions).  Even with a tensioned 
> solid suspension, large tracking tabs are beneficial.  Joe's little Hetzer 
> is a well designed and executed vehicle with a solid suspension, but he 
> went with OTS plastic conveyor tracks that have tiny little tracking tabs. 
>  As a consequence, Joe's gotten very good at track remounting in the middle 
> of a battle.  With an active suspension, where the track runs loose around 
> the wheels, tracking tabs are the only thing keeping things were they 
> belong.
>
> In my designs, I build as large a tracking tab as possible with no regard 
> to scale.  This is for performance sake as I'm a "gamer" where function 
> comes first and scale a distant second.  This offers a quandary for you as 
> your designs are most decidedly scale first.  To offer 
> a performance suspension for gaming, are you willing to redesign the entire 
> suspension?  We're talking not only larger tabs, but also the wheels and 
> drive sprockets to accommodate them, maybe drop the segmented 
> tracks altogether and go with a TTS belted design?  Is there a market to 
> support the time, effort, and expense?  All good questions.
>
> Steve Tyng
>
>
> 
>


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Re: [TANKS] Re: cheap laser distance range finder with USB output

[Joe Sommer]

On Sunday, April 14, 2013 9:41:02 PM UTC-4, RocketMan wrote:
>
> Now, I guess I HAVE to see if it actually works…
>
> "I’m not even sure they’d need to pivot. It would be great not to use 
> moving parts for this if possible. Cheap webcams now have a 1280 pixel 
> horizontal resolution. If you separate two of those, facing straight ahead, 
> by a known distance then you could calculate the physical distance based on 
> the pixel separation of an image feature.
>
Doug,
 
Do not bother doing the trigonometry.  You will ultimately
need to measure camera separation distance, focal length 
of each camera and lens distortion (barreling, pin cushion)
which can be difficult to do accurately.
 
I will dig out an algortihm that we used  in the bad old days of
photogrammetry called the Direct Linear Transform (DLT).  See
https://me363.byu.edu/sites/me363.byu.edu/files/userfiles/5/DLTNotes.pdf
 
It inherently includes intrinsic camera paramters (focal length
and lens distortion) and extrinsic camera parameters (focal
point location and prinicipal axis orientation).
 
To calibrate, you place a grid of points printed on a flat
plate at several known ranges and measure pixel locations
of the points.  The algoithm then calculates binomial coefficients
that provide simple computation of global locations for
a point that is visible to both cameras.
 
We used it for photogrammetry in biomechanics of human 
movement for scientific analyses similalry to multicamera
motion capture for computer generated images in movies
(e.g. Golem in LOTR).
 
Joe
 

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