Need advice about fire-fighting TICs - Page 1
Forum section: electronics / general

author: Logan
author_rank: Frequent Contributor
timestamp: September 01, 2021, 01:42:14 pm
content: Hi guys.My brother want to get a thermal camera, and I think a used fire-fighting TIC is a good choice for him, because it's inexpensive, while having good resolution, frame rate, and FOV, the only downside is the size and weight, but per himself, it's acceptable.However I've never owned such a camera myself (although I saw a lot in this forum), so I want to know one particular thing that can only be answered by actual users, instead of reading the specs: what would the performance(picture quality) when use fire-fighting TICs in daily environment? When viewing low delta scenes, how the details can be seen compare to a consumer device?(such as my Seek)I did some searching and found that for those old TICs, A-Si sensors are pretty bad, the image is just flat without something on fire, but I'm hesitate between VOX and BST. BST seems to have the best contrast even through the NETD number is higher, which means more noise. While VOX seems to show less noise, but they seems to have lower contrast as well.So are there anyone have experience with both type TICs(maybe Fraser/Bill?) that can even compare them to tell me, which one shows more detail in a thermally-flat environment?Also, are there any notable difference among different vendors for VOX? (such as Flir, BAE, DRS...)Thank you!

author: Fraser
author_rank: Super Contributor
timestamp: September 01, 2021, 02:36:34 pm
content: The good news is that fire fighting thermal cameras can produce excellent imagery, even in low Delta T scenes. They employ very good quality imaging cores and provide the required wide temperature capability needed for a fire fighting camera by using two or three temperature ranges. The most sensitive range is normally -20C to +120c and equivalent to that of most generic thermal imaging cameras. If the scene contains a higher temperature source than 120C, the camera switches to a lower sensitivity mode in order to correctly image the scene with its high Dynamic range from background to very hot. Some cameras have a third range with even lower sensitivity in order to cope with very high temperatures. Ambient temperature low Delta T scenes often look very low contrast in the medium and low sensitivity modes and this is perfectly normal. The high sensitivity range provides all the required detail of a low Delta T scene.What a fire fighting camera lacks is the multitude of colour palettes found on many general purpose cameras and they tend to be ‘fully automatic’ in terms of the displayed span and centre temperature. Sometimes the older cameras LCD displays do not reproduce the thermal image that well and better results can be obtained with a more modern LCD display.Many fire fighting cameras can easily see the plaster dab spots on the walls of a plasterboard lined house and that is a decent quick test for low Delta T capability. The MSA5000 series camera that I dismantled contained a Indigo/FLIR Omega/M10 imaging core with 160 x 120 pixel resolution. That core was designed for military applications and is a decent performer, even today.Fire fighting cameras are a good source of good quality imaging cores and it is often the case that the core offers more capabilities than provided in the fire fighting embodiment. An example is the Raytheon/L3 3500AS, 3600AS and 4500AS cores found in many fire fighting cameras. It was a very capable and versatile imaging core series that were designed for military applications but were also used in fire fighting embodiments due to their excellent performance.Fraser

author: Logan
author_rank: Frequent Contributor
timestamp: September 01, 2021, 03:09:08 pm
content: Thank you Fraser!We don't care much about color palettes or measurement.So could you tell which type of core tend to produce more distinguishable details, VOX or BST? If VOX, are difference among vendors significant?

author: Bill W
author_rank: Super Contributor
timestamp: September 01, 2021, 04:34:12 pm
content: First off I did not do that much with VOx, mainly as export to the UK was a pain we never ventured into using them for cameras at a serious level.A BST will usually be better than a VOx of the same era, and both far better than an ASi.That is for around year 2000 Argus2 / Argus3 era. The older ASi (Argus3 blue, Bullard T3) are going to be a bit grim as you mentionMoving on to 2010 era VOx were very good sensors and cores but often suffered by cheapening elsewhere. A FLIR1 is a VOX afer all.... Also by this era the ASi were getting pretty good so should not be discounted, while the inevitable bulk of a BST counts against it in a head-to-head.ISG and MSA should be pretty good as well as Argus2 and the yellow (BST) Argus3. Be a bit more careful if looking at any Argus4's as those did vary a lot in sensor inside and most sellers do not care to say which is which. Stick to P7130 and P7150 serials.All fire cameras will do something to deal with high heat scenes, but what will differ. Some will lose all contrast (mainly those Raytheon 3500AS based) while others will increase noise in the cooler areas (Argus). However as Fraser notes, for most domestic use under 150°C (300°F) they will be in high sensitivity 'casualty search' mode and so similar to any thermography cameras that use the same cores. No problem finding hot pipe runs underfoor with an Argus2 (BST)I have some BST videos up on YouTube to go with a camera on eBay just now that might be of interest (sorry no sales to USA)https://www.youtube.com/channel/UCIYJyOc2KEuIbpjTiFVPBVw/videosand these links on fire-ticshttp://www.fire-tics.co.uk/Argus2_CD/explained.htmDomestic still images from BSThttp://www.fire-tics.co.uk/Argus3_CD/files/kettle.aviBoiling kettle video - see the mains lead glow - BST Argus3Bill

author: Ultrapurple
author_rank: Super Contributor
timestamp: September 01, 2021, 05:01:25 pm
content: I have cameras with A-Si, VOX and BST, so I can add my general ignorance to the topic.ModernA-Siiscan be pretty good, but as Bill says the earlier versions (even some of the early Seek cameras) can be poor.VOX is good and gives clean images, though all VOX sensors have slight 'fixed pattern noise' that's most visible atverylow temperature span scenes (1 to 2°C total). The digital processing gets rid of most, if not all of this, in normal use.BST sensors have no fixed pattern noise and are of generally comparable sensitivity to VOX sensors of the same era. But all BST cameras necessarily have a mechanical 'chopper' (usually a rotating spiral), which is required due to the way BST works. Also, images from BST sensors often have a characteristic 'halo' effect around bright or dark objects (this is often seen as a Good Thing because it can enhance images).A-Si and VOX cameras may or may not be radiometric, ie they may or may not giveactual-temperature information (at whatever degree of accuracy they were calibrated to, rarely closer than ±1°C). BST sensors cannot be radiometric, but some BST cameras (notably the Argus 3) have a separate spot (one-pixel) sensor, whose reading is superimposed on the video display.

author: Bill W
author_rank: Super Contributor
timestamp: September 01, 2021, 07:02:23 pm
content: Quote from: Ultrapurple on September 01, 2021, 05:01:25 pmIt is not one pixel, it is the business end of a 20:1 Raytek spot temperature gun, so covers about 20 pixels - hence the biggish box to fill on screenBill

author: Ultrapurple
author_rank: Super Contributor
timestamp: September 02, 2021, 07:42:39 am
content: @Bill W - Thanks; I sit corrected.

author: Bill W
author_rank: Super Contributor
timestamp: September 02, 2021, 10:28:43 am
content: Quote from: Ultrapurple on September 02, 2021, 07:42:39 amCame across a bit harsh, the *RAYTEK* component was indeed a single point detector but it is not one pixel on the camera image / screen.Here is the unit as fitted inside the camera case of an Argus3. Very simple to use, just feed it 5V and the temperature (average of the ~5 degree cone) comes back as 10mV/°C so 0 - 500°C is 0 to 5V

author: Logan
author_rank: Frequent Contributor
timestamp: September 02, 2021, 01:32:44 pm
content: Thank you everyoneYou are really helpful!