Author Topic: Uni-t UTi260B  (Read 15210 times)

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Offline edigi

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Re: Uni-t UTi260B
« Reply #25 on: November 18, 2020, 04:29:32 pm »
Probably you're right, spec-wise it's a good match.

I've checked the link and it occurred to me very soon what's the clicking noise: Aperture (or is diaphragm the correct word?) change.
I don't know if it's common with all such cameras but the purpose is the very same as with photo cameras: The amount of light can be controlled so good sensitivity can be kept without over driving the sensor in case of strong light (heat) source.
I just did not expect it to be used also here.
 

Online Fraser

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Re: Uni-t UTi260B
« Reply #26 on: November 18, 2020, 05:58:26 pm »
It is the mechanically operated Flat Field Correction (FFC) flag being activated to correct for pixel drift in the sensor array. Most microbolometer based cameras have them but some manage to avoid using an FFC flag by using compensation tables and maths. Some high temperature cameras do have a calibrated diaphragm that is brought into the optical path to assist the microbolometer in coping with the high levels of energy present in high temperature situations. Not a common item on budget cameras however.

Fraser
« Last Edit: November 18, 2020, 06:04:00 pm by Fraser »
Cogito, ergo sum
 
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Offline edigi

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Re: Uni-t UTi260B
« Reply #27 on: November 18, 2020, 06:48:42 pm »
Thank you, I think I've learned something also in this area today.

Is guess FFC is somewhat comparable to dark noise (current) extraction of astro cameras but it tries to do a pixel sensitivity calibration at the same time, doesn't it?
I've made a quick check of the acronym but to me it's not obvious how the uniformity of pixel sensitivity is achieved.
Is some reference object placed very briefly in front or the sensor? is that then the clicking noise?

UPDATE: I've checked the clicking noise once more: It's roughly periodic with a 5-6s period (maybe it also depends on a lot of factors like ambient temperature etc.) and after the click the LCD update freezes for roughly 0.5s. This frequent correction is crazy but I couldn't find a way in the manual to make it less frequent.
« Last Edit: November 19, 2020, 03:51:24 pm by edigi »
 

Offline chofroa

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Re: Uni-t UTi260B
« Reply #28 on: November 20, 2020, 11:11:03 am »
Hello,

. is there, in the caracteristics of this camera, any one(s) that would make it inappropriate or less appropriate for a home inspection ?
https://www.uni-trend.com/html/product/NewProducts/UTi%20industrial%20Series/UTi260B.html
Specifications
Model        UTi260B
Certifications    CE/RoHS
Temperature range      -15~550℃
IR resolution        256x192 pixel
Field of view (FOV)    56°x 42°
Thermal sensitivity (NETD)    50mk
Spatial resolution (IFOV)    3.8mrad
Frame rate        25Hz
Measurement accuracy    ±2℃ or ±2% whichever is greater
Palettes        7
Emissivity    Adjustable (0.01-1)
Focus        Focus free
Display modes     Thermal, blending, visible, PIP
Display       2.8”LCD
ROI (eliminates interference)    √

. what could be the distance min and max from the target to measure ?

thanks !
 

Online Fraser

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Re: Uni-t UTi260B
« Reply #29 on: November 20, 2020, 11:40:58 am »
From the provided specification, the UTI-260B will be OK for personal home inspection purposes. It is not up to the standard expected for commercial home energy audits and building inspections though.

The unit has a relatively wide 56 degree horizontal field of view which suits both interior and close range exterior building inspection. Minimum focus distance from the fixed focus lens will be around 1 metre and it will provide reasonable focus all the way to infinity. Practical measurement distance is likely to be limited by the resolution as the pixel size ‘on-target’ gets larger the further away you get. The IFOV is 3.8mrad so you can use that to see how large a measurement pixel is on the target at a particular distance.

This camera appears to be a reasonable ‘general use’ budget product that will meet the less demanding users needs. I would place it in a similar category to the Seek Thermal Dongles and Reveal series in terms of market segment. In terms of price, it looks to be value for money but you do get what you pay fir so expectations needs to be managed.

Fraser
« Last Edit: November 20, 2020, 12:11:35 pm by Fraser »
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Online Fraser

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Re: Uni-t UTi260B
« Reply #30 on: November 20, 2020, 12:06:25 pm »
edigi

The FFC event is used by the core to recalibrate its temperature measurement system and to maintain a relatively flat field output from the pixels. It is some times called “touch-up” as the FFC trims the pixel gains to maintain a nice even output for a given input across the whole sensor array. Without the FFC event or a replacement mathematical correction, the image can degrade due to pixel drift and measurement accuracy is also degraded.
The FFC flag acts as a thermally flat scene in front of the microbolometer against which the image processing and measurement systems calibrate. The period between FFC events is dependant upon several factors including the manufacturers preference for the intended use. An FFC event is normally periodic, as set in the cameras configuration but may be instigated at will be the user or when the cameras ambient temperature changes significantly.

When a microbolometer based thermal camera is first switched on, the microbolometer die begins to warm up to normal operating temperature and stabilises at a point of equilibrium that is often in the range 30C to 34C. During the warming up period that can last up to 2 minutes, the FFC events occur more regularly as the camera self calibrates to compensate for the temperature rise in the microbolometer. Once the camera has warmed up to operating temperature the frequency of FFC events drops back to the period set by the manufacturer for ‘maintain accuracy and flat field’ purposes. The period is chosen based upon the manufacturers experience of the microbolometers behaviour during environmental testing at the design stage. As stated, a common FFC event interval is 2 minutes but some cameras permit this interval to be changed or even switched off altogether for video recordings etc.

In the case of the Seek Thermal thermal imaging cores, we saw a very regular FFC event but the duration is very short. SEEK Thermal are regularly applying the FFC event to maintain their microbolometers flat field and accuracy. It could be that the microbolometer is somewhat thermally unstable or it may be a way to maintain image quality on the 12um pixel based tiny microbolometer. It would seem that the Imaging core in the UTi-260B behaves in a similar way. It is unlikely that the FFC event period can be changed on this budget camera. This may just be something that must be tolerated as part of owning an inexpensive thermal camera. There is no such thing as a free lunch in life ;)

Fraser

« Last Edit: November 20, 2020, 03:20:16 pm by Fraser »
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Offline chofroa

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Re: Uni-t UTi260B
« Reply #31 on: November 20, 2020, 01:48:46 pm »
thank you very much Fraser,

Quote
It is not up to the standard expected for commercial home energy audits and building inspections though.

may I ask you what caracteristics/numbers you would mainly look for ?
 

Online Fraser

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Re: Uni-t UTi260B
« Reply #32 on: November 20, 2020, 01:56:38 pm »
This article should answer your questions.

https://irinfo.org/04-01-2014-warner/

Fraser
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Online Fraser

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Cogito, ergo sum
 
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Online Fraser

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Re: Uni-t UTi260B
« Reply #34 on: November 20, 2020, 02:07:45 pm »
Cogito, ergo sum
 
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Online Fraser

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Cogito, ergo sum
 
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Online Fraser

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Re: Uni-t UTi260B
« Reply #36 on: November 20, 2020, 02:12:22 pm »
Cogito, ergo sum
 
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Offline chofroa

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Re: Uni-t UTi260B
« Reply #37 on: November 20, 2020, 02:35:15 pm »
thanks, I go reading :)
 

Offline edigi

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Re: Uni-t UTi260B
« Reply #38 on: November 20, 2020, 03:04:24 pm »
I've made a quick series of my GPSDO (serial socket as main subject) from approx. 15, 10 and 5cm distance to show how close distance photos look like.

Even 10 minutes after switch on clicking is as frequent as 10 sec.
[attachimg=1][attachimg=2][attachimg=3]
« Last Edit: November 20, 2020, 03:07:05 pm by edigi »
 
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Offline discrete

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Re: Uni-t UTi260B
« Reply #39 on: December 05, 2020, 10:18:13 pm »
Got my unit in yesterday.

+ It works about as well as expected and nothing to complain about the basic design or user interface.
+ The resolution is high enough to not need the visible light camera image mixing. This is fortunate, because the visible light image has some lag and does a snail trail when panning.
+ The PC app is basic but responsive. You can have a live mirror of the imager's screen, or play around on the recorded images to get point readings.
- Initially I had one or two startup- hiccups and it even reverted to Chinese once. These problems went away once I fully charged the battery. But it hints to flaky power management or a bad/missing cap somewhere.
- It seems to be held together with screws, but the screws are hidden below glued rubber inserts. So will be tricky to swap out the battery when eventually needed.
- Unfortunately my unit developed a kind of 'hot spot' after the first few uses. It was fine in the morning and when I used it again in the afternoon I had this:

[attach=1]

Of course it is somewhat exaggerated in that 'flat' image that spans only 2 C, but when you know it is there you can see it on most images.

Here is a span of 10 C:

[attach=2]

And with a different palette:

[attach=3]



« Last Edit: December 05, 2020, 10:24:16 pm by discrete »
 
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Offline Vipitis

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Re: Uni-t UTi260B
« Reply #40 on: December 06, 2020, 12:06:06 am »
that is not a hot pixel or line. It seems like some debris on either lens or sensor. Or a wrong correction, because it is actually warmer.
 

Offline analogRF

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Re: Uni-t UTi260B
« Reply #41 on: December 06, 2020, 07:33:16 pm »
I would like to get this thermal camera but my only use (almost) is looking at circuit boards and inside instruments looking for hot components

so can somebody confirm if this camera is suitable with acceptable resolution (I mean differentiating between closely spaced components)?

can someone post some thermal pictures of a circuit board at various distances, please?

thanks
 

Offline discrete

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Re: Uni-t UTi260B
« Reply #42 on: December 09, 2020, 02:51:32 am »
This is at 10-12 cm from the top board. Focus is not great, but it does a reasonable job.
Three of the 7 available palettes, visible images also included for comparison.

There is an option to mix the visible and IR image in steps of 25% opacity, but image offset makes it kind of useless at short range.

 
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Offline edigi

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Re: Uni-t UTi260B
« Reply #43 on: December 09, 2020, 07:11:51 am »
RPi4. Those components next to the USB-C plug are 3-5mm ones.
All pictures are probably taken closer than the min distance spec of the camera (0.25m).

So while it can be used to check PCBs to a certain extent it's far from ideal.
If you need to check small SMD components (like 0805 or even 0612) and you use the camera almost exclusively for this look for a camera that has adjustable focus. Fixed focus cameras like this result in blurred images if you move it too close to the PCB (that is required as it does not have very good spatial resolution).

I don't know if special macro lens could improve this. I'd be also definitely interested to try one if someone could recommend such reasonable priced variant that works also with this fixed focus camera (I can 3D print, so mounting would not be an issue).

Note: I always have to convert the camera images to jpg as the forum engine does not seem to like bmp.
[attachimg=1][attachimg=2][attachimg=3]
 
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Offline frenky

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Re: Uni-t UTi260B
« Reply #44 on: December 09, 2020, 09:15:27 am »
This is at 10-12 cm from the top board. Focus is not great, but it does a reasonable job.
Based on tech specs "Focus: Focus free" it has fixed focus lens.
Perhaps lens are mounted on plastic screw so you could screw them out more to get closer focus.

There is always an option of mounting cheap ZnSe lens with focal length between 50mm and 100mm in front of existing lens to get sharp focus at close range.
https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2334524.m570.l1313&_nkw=znse+lens&_sacat=0&LH_TitleDesc=0&_osacat=0&_odkw=znse+100mm
« Last Edit: December 09, 2020, 09:19:28 am by frenky »
 
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Offline analogRF

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Re: Uni-t UTi260B
« Reply #45 on: December 09, 2020, 01:34:19 pm »
RPi4. Those components next to the USB-C plug are 3-5mm ones.
All pictures are probably taken closer than the min distance spec of the camera (0.25m).

So while it can be used to check PCBs to a certain extent it's far from ideal.
If you need to check small SMD components (like 0805 or even 0612) and you use the camera almost exclusively for this look for a camera that has adjustable focus. Fixed focus cameras like this result in blurred images if you move it too close to the PCB (that is required as it does not have very good spatial resolution).

I don't know if special macro lens could improve this. I'd be also definitely interested to try one if someone could recommend such reasonable priced variant that works also with this fixed focus camera (I can 3D print, so mounting would not be an issue).

Note: I always have to convert the camera images to jpg as the forum engine does not seem to like bmp.
[attachimg=1][attachimg=2][attachimg=3]

still  it's not that bad. how does it look like if you do look at the board at 25cm?
variable focus thermal cameras are way beyond anything I can pay :-(
even this one is not so cheap unless you have more than one application for it so i'm still undecided  :-//
 

Offline edigi

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Re: Uni-t UTi260B
« Reply #46 on: December 09, 2020, 03:03:11 pm »
how does it look like if you do look at the board at 25cm?

The spatial resolution (IFOV) of this camera is 3.8mrad as per data sheet. That means that around 25cm each pixel corresponds to roughly 1mm (unless I've miscalculated it), so although the picture will be slightly less blurry (the transition is continuous) you won't get more detail (actually less; and also as hotspots are smeared a bit, so lower temperate will be measured as in reality or when you move the camera closer).
If you check my earlier photo of the keyboard of my laptop that's was made from around 25cm distance.

I plan to make a try with the ZnSe lens proposed above (unfortunately any shipping takes ages and is totally unreliable nowadays so it won't happen anytime soon).
 
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Offline picazzo

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Re: Uni-t UTi260B problem
« Reply #47 on: December 28, 2020, 04:24:31 pm »
Hello, I bought a uni-t uti260b thermal camera, but for some time the video and photos still show two points in the same place (marked) that falsify the measurements are quite large, about 5 mm in diameter. What can it be, thank you.
 

Online Fraser

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Re: Uni-t UTi260B
« Reply #48 on: December 28, 2020, 07:22:54 pm »
Those appear to be caused by contamination of the microbolometer window with specs of dirt.

This could be caused by poor build area hygiene or rubbish inside the cores casing that moved onto the microbolometer in transit. Accessing the microbolometer to inspect it may not be a simple task depending upon how the OEM constructed it and whether any screws are hidden under labels etc.

If you can access the microbolometer you will likely need to remove the lens by unscrewing it and look at the microbolometer window under magnification. Cleaning the window must be done with great care and in some cores, such as the Seek Thermal types, the FFC flag sits across the microbolometer window when the camera is off.

If you can send the camera back for an exchange, I recommend that you take that path.

Fraser
« Last Edit: December 28, 2020, 07:30:16 pm by Fraser »
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Offline picazzo

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Re: Uni-t UTi260B
« Reply #49 on: December 31, 2020, 07:46:07 pm »
Thank you for the answer, unfortunately it will be difficult, although the price was a bargain, I noticed it only after some time. Generally, the housing is dust-proof and impact-resistant, but there is dust in it, can it be lightly blown with compressed air from a sufficient distance?
 


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