Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: Keavon on June 01, 2011, 05:06:22 PM

Title: Cheap Thermal Camera?/Best Way to Detect Location of Human/Animal?
Post by: Keavon on June 01, 2011, 05:06:22 PM
Hello!
I'm going to be building a gun turret (my website for the project is www.turret.tk (http://www.turret.tk)) and am wondering what's the best way to track the person? With motion software, I will be risking it shooting at trees or something not an animal/human. I want to use a thermal camera, but most of them seem like $5,000+ and have their own display on them. All I want is some really low resolution thermal camera so I can write a program to shoot at the biggest heat source above a certain color.
Is it possible to make a thermal camera or sensor that detects an image of heat (it must know an exact location for aiming).

Also, if there are any other ways to do this, please let me know!
Thank you!

-Keavon
Title: Re: Cheap Thermal Camera?/Best Way to Detect Location of Human/Animal?
Post by: rbtying on June 01, 2011, 08:32:33 PM
Use a normal webcam, remove the IR filter, and block visible light from it.  It won't be the best, but it'd suffice, I think.  The reason thermal cameras are expensive is because an accurate temperature reading is expensive at any range above a few centimeters - but for finding a max (probably indoors), a webcam may work.

Of course, for person detection, you could just run some more advanced vision processing code. 
Title: Re: Cheap Thermal Camera?/Best Way to Detect Location of Human/Animal?
Post by: Keavon on June 02, 2011, 08:51:10 AM
Thank you for your quick reply!
I'll Google how to do it.
But my only question is, does an IR camera really pick up heat? Looking at some IR photos, they don't seem to light up heat sources like people at all. And aren't IR cameras what they use for night-vision? That's not viewing heat.
Are you sure that an IR camera will work for heat sensing? Thank you!
Title: Re: Cheap Thermal Camera?/Best Way to Detect Location of Human/Animal?
Post by: adanvasco on June 02, 2011, 09:45:24 AM
How about using an IR thermometer mounted on a servo? You can always use a range finder to determine the distance to the object. One of those thermometers can be easily obtained for less than $5. You would just need to hack it to make it work in your project. 1k times cheaper though.

Just a thought.
Title: Re: Cheap Thermal Camera?/Best Way to Detect Location of Human/Animal?
Post by: Soeren on June 02, 2011, 03:44:13 PM
Scan a pyroelectric sensor (as found in a PID sensor) with a grating/Fresnel lens back and forth (or better, rotate it) - that way it cannot be fooled by a person standing still.
It will detect even minute temperature changes crossing it and may have to be desensitized a bit.
Title: Re: Cheap Thermal Camera?/Best Way to Detect Location of Human/Animal?
Post by: Keavon on June 04, 2011, 05:55:12 PM
How about using an IR thermometer mounted on a servo? You can always use a range finder to determine the distance to the object. One of those thermometers can be easily obtained for less than $5. You would just need to hack it to make it work in your project. 1k times cheaper though.

Just a thought.

If I can actually get it for less than $5, maybe I could use a PID setup in the eye to sense not where if when a target gets in range so it can open up, then use an array of many of those thermometers pointing in different directions, mounted on the gun panels to know exactly or roughly where the target is?
If they are so cheap, and assuming I can get them small enough, then that might just work.
I might also be able to mount multiple ones on a single axis, then scan back and forth with a motor in only one direction.
Thank you for your ideas! I hope there is an easy and cheap solution.
-Keavon