Author Topic: Yet another cheap thermal imager incoming.. Seek Thermal  (Read 679697 times)

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Offline termal lee

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2125 on: October 11, 2015, 12:11:08 pm »
seems like Ge is more resistant of scratches. and the material alone, is more expensive.
IR lenses in general are so expensive. lets wait until Seek releases their chalcogenic lenses instead.

and, did someone notice this in ebay?

XR's PRICE IS 228$ !!!
 

Offline jeffreythe00

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2126 on: October 11, 2015, 11:12:34 pm »
If anyone is looking for a solution to cleaning the optics of their thermal camera or any other optics for that matter. There is a company that makes a FANTASTIC cleaning solution. I use it myself to clean laser lenses and camera lenses and have not had any issues with it. Its called First Contact and it is sold here. http://www.photoniccleaning.com

This solution is delicate enough to clean laser dies which are only a few µm in size. I can confirm this.
 

Offline termal lee

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2127 on: October 12, 2015, 03:17:30 am »
nice info there, jeffrey, but this is for "dirty amateurs of seek", i will go with Fraser's IPA+soft cloth.
nonetheles, i will remember to use ur option when i am into high powered laser devilce, which i am going to get into, pretty soon  :-+
 

Offline jeffreythe00

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2128 on: October 12, 2015, 04:15:48 am »
No problem termal lee!

On the note of high powered laser devices, another good solution to getting your optics dust free is to use cotton swabs (not qtips because the glue can/will deposit on your optics. Not good) and lab grade methanol.

99.9% Methanol is much cheaper than First Contact and works very well but it is hydrophobic so not ideal if you store it for long periods of time.
« Last Edit: October 16, 2015, 01:43:22 am by jeffreythe00 »
 

Offline termal lee

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2129 on: October 15, 2015, 07:49:29 pm »
verry well noted. thanks jeffrey  :-+
 

Offline lod

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2130 on: October 17, 2015, 01:16:13 am »
Just a note to recent readers that I have summarised much of this thread in a publicly editable wiki
https://github.com/lod/seek-thermal-documentation/wiki

I am still routinely reading this thread for updates in addition to direct contributions.
 

Offline tomas123

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2131 on: October 17, 2015, 04:10:21 am »
Thank you for your wiki.

I know something about the Flir sensor values and I'm reading here by the way that seek make a linear interpolation.
https://github.com/lod/seek-thermal-documentation/wiki/Temperature-Values
Quote
kelvin(x) = -18.763 + 0.0378683*x Kelvin

Flir has a nice document:
http://flir.custhelp.com/ci/fattach/get/1667/
on page 2 they say, that the response of "A/D Counts" are linear to Radiance [Joules/m^3/sec/steradian] with an offset.

This make also sense for Seeks microbolometer.
I know, that the function temperature=f(radiance) is similar to linear  in our small temperature range but not exact.

I wrote here some details
http://u88.n24.queensu.ca/exiftool/forum/index.php/topic,4898.msg23944.html#msg23944
Quote
The Radiance formula you find in Planck's Law
http://en.wikipedia.org/wiki/Planck%27s_law

e^(h*c/(k*L*T)-1 = (2*h*c^2/L^5)/I
Planck’s Constant h = 6.626068x10-34 joule sec 
Boltzman’s Constant k =1.38066x10-23 joule deg-1
Speed of light in vacuum c =2.997925x10+8 m/s
T = object temperature in Kelvins
L = wavelength in m
I = radiance in Joules/m^3/sec/steradian
e Euler Number

solve it to Temperature formula
T= B / ln(R/I +1)
with ln => Natural logarithm
by substitute with
R = 2*h*c^2/L^5 
B = h*c/(k*L)

as explained above is Radiance "I" linear to  Flir A/D Counts "S"
we can write
I = R2*(S+O)
with
S = 16 Bit A/D Counts
R2 = constant factor
O = offset

and with R = R1/R2
T= B / ln(R/I +1)
goes to
T = B / ln(R1/(R2(S+O))+1)
« Last Edit: October 17, 2015, 11:29:52 pm by tomas123 »
 

Offline tomas123

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2132 on: October 18, 2015, 04:52:44 am »
Quote
kelvin(x) = -18.763 + 0.0378683*x Kelvin

that the response of "A/D Counts" are linear to Radiance  with an offset.
one day later and no reaction  :-//

for better understanding I made a excel sheet

the Flir E4 has a spectral range from 7.5–13 um (the peak 10.6 um) http://support.flir.com/DsDownload/Assets/63901-0101_en_50.pdf
 
I wrote a table for the planck law at 10600 nm wave length over the temperature range
There you can see, that the spectral radiance in [W / m^2] (per nm wave length) is not exact linear



source: http://www.ces.karlsruhe.de/culm/culm/culm2/th_physik/simulation/planck.xls
« Last Edit: December 21, 2016, 10:37:02 pm by tomas123 »
 

Offline frenky

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2133 on: October 18, 2015, 08:26:53 am »
Sorry for late response but when I saw your first post I was like.... emmm ok....  ;D And the second post didn't help a lot. :-//

If I understand you correctly you have found a formula "kelvin(x) = -18.763 + 0.0378683*x Kelvin" that converts seeks raw pixel data into temperature?

My big dilemma now is: Should I put another n*10 hours of development into custom SeekThemal software, to make it better or just sell it and forget about it.
(And buy I3-ThemalExpert when it becomes available in a few days/weeks...)

I took a shot at custom software a few months ago with stepper motors and super-resolution, but that was too hardware dependant and to clumsy to use when I wanted to make a thermal image of a pcb.

If I decide to try again I'll go from the scratch:
- direct seeks module at thermal plane with the same temperature
- record a value of each pixel at 20*C, 50*C and 100*C after 1minute, 5minutes, 10minutes, 1hour
- map all bad pixels (dead and "patent" pixels and calculate best values)
- just ignore frames of data taken with shutter closed
- perhaps attach a small Peltier element on the back of the seek to prevent huge thermal drift?

That should be enough to make a software that would produce really clean 206x156 images...
« Last Edit: October 18, 2015, 08:29:27 am by frenky »
 

Offline tomas123

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2134 on: October 18, 2015, 08:46:15 am »
If I understand you correctly you have found a formula "kelvin(x) = -18.763 + 0.0378683*x Kelvin" that converts seeks raw pixel data into temperature?
No, this is not my idea.

After reading this page
https://github.com/lod/seek-thermal-documentation/wiki/Temperature-Values
Quote
kelvin(x) = -18.763 + 0.0378683*x Kelvin
... I thought, that seek users make a linear interpolation between this poor reference points.

It's possible, that seek get A/D values from microbolometer like Flir, where RAW=functions(Radiance).
Only a suggest...
To illustrate this non linear relation, I wrote the Excel sheet.

I'm not a seek user. I only poked about in this forum.
« Last Edit: October 18, 2015, 08:51:19 am by tomas123 »
 

Offline brobbuilder

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2135 on: October 18, 2015, 03:47:30 pm »
Someone should hack together a Lytro-style superdepth camera with Seek or Lepton modules. I'm looking at you, mikeselectricstuff...
 

Offline encryptededdy

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2136 on: October 18, 2015, 04:37:40 pm »
Someone should hack together a Lytro-style superdepth camera with Seek or Lepton modules. I'm looking at you, mikeselectricstuff...
To do that wouldn't you need a camera with a relatively shallow depth of field?

Neither the Seek nor Lepton fit that bill due to small sensors and high f/stop lenses.
 

Offline encryptededdy

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2137 on: October 26, 2015, 09:25:07 pm »
http://inteliscopes.com/thermal-2/

Hmm... a questionable application for the Seek XR.

I wonder how well the Seek will work as a rifle scope considering it's low frame rate, constant shutter actuations and questionable sensitivity.

Especially after looking at Mike's teardown, I can't see that shutter assembly holding up to recoil very well.
 

Offline Uho

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2138 on: October 26, 2015, 09:42:48 pm »
Pig so will look on the screen from a distance of 8m. Where are they going to hunt? On a farm in California?
 

Offline arsenix

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2139 on: October 27, 2015, 12:26:01 am »
Somewhere in the fine print: "For hunting domestic pigs only from distances of no more than 10 feet."

Great CAD renderings though...
 

Offline frenky

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2140 on: October 27, 2015, 10:47:58 pm »
I decided to write a new version of Win software for Seek.

First step, know your enemy.  ;D

I'll take a raw reading of all pixels in 5sec intervals for 1 hour while pointing to uniform temp plate. This will show me the how big error each pixel has and thermal drift of each pixel though time.

I'm currently using a cork plate for uniform temperature reference (at room temp). Do any of you have a better suggestion?


Next step will be to make some kind of heating plate to take measurements of pixel values at 100*C.
What would be best approach for this. Perhaps a heat bed of 3d printer? Big peltier element?
I need something that will produce really uniform temperature plane.

Tnx for all suggestions.
« Last Edit: October 27, 2015, 11:00:33 pm by frenky »
 

Offline frenky

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2141 on: October 28, 2015, 05:44:20 am »
Drifting of 8 random pixels in 1 hour. On some pixels temperature readings go up and on some readings go down.
As you can see thermal pixels need at least 20min to output stable readings.



Explanation of values:
Dark red line is a pixel which starts with value 7537 and ends with 6818. That is 719 less.
« Last Edit: October 28, 2015, 05:49:54 am by frenky »
 

Offline encryptededdy

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2142 on: October 28, 2015, 07:58:02 am »
Drifting of 8 random pixels in 1 hour. On some pixels temperature readings go up and on some readings go down.
As you can see thermal pixels need at least 20min to output stable readings.



Explanation of values:
Dark red line is a pixel which starts with value 7537 and ends with 6818. That is 719 less.
I guess that explains the excessive shutter actuations that we see on the Seek.
 

Offline frenky

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2143 on: October 28, 2015, 10:30:07 pm »
There is more weird stuff going on...

Some pixels shift raw values after each shutter calibration. So pixel value is fluctuating like this: 8500,6700,8500,6700...
 

Offline encryptededdy

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2144 on: October 29, 2015, 06:19:56 pm »
Seek posted this on their Facebook page. It appears to be from the Reveal.

 

Offline frenky

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2145 on: October 29, 2015, 06:42:24 pm »
It's not bad quality and ratio is correct. But after fake marketing images fiasco I don't trust them any more...
It could be that they are using special "lab" version of Reveal which produces better images than production version.
 

Offline Fraser

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2146 on: October 29, 2015, 08:27:25 pm »
The marketing video of the Reveal is appallingly misleading to potential buyers. This latest image is more like I would expect. Plenty of noise evident.
« Last Edit: October 29, 2015, 08:33:49 pm by Fraser »
 

Offline frenky

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2147 on: October 30, 2015, 05:28:59 am »
Live graph of pixels raw values.
When pointing at 19*C uniform temp plate pixels have values from 6000 (up slope of the chart) to 9000 (down slope).
Middle of the hill is at 7500 so I guess that 7500=19*C.

 

Offline daves

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2148 on: October 31, 2015, 01:50:59 am »
Seek is piece of crap - imho.
Batch Thermal Images Editor (JPG, BMT, SNP, IRI, ISI, IS2, PGM, TIF, IMG, BMP):  http://www.eevblog.com/forum/testgear/flir-e4-thermal-imaging-camera-teardown/msg350556/#msg350556
 

Offline encryptededdy

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Re: Yet another cheap thermal imager incoming.. Seek Thermal
« Reply #2149 on: October 31, 2015, 12:34:39 pm »
Seek is piece of crap - imho.
Piece of crap when compared to their advertising images? Yes.
Piece of crap when compared to other 200x150 thermal cameras? Yes.

But Piece of crap compared to other imagers in the same price bracket? I don't think the Seek is too bad in that case.
 


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