Color palettes - Page 1
Forum section: electronics / general

author: eKretz
author_rank: Frequent Contributor
timestamp: June 07, 2018, 08:29:57 am
content: Which color palettes do you guys find most useful for thermal imaging? I would imagine it differs depending on application - like I could see the Flir "iron" palette being useful for electronics and home inspection, but for detecting animals a white hot or black hot "gray" palette might be better. Can the Flir cameras like Ex or Exx series be switched from white hot to black hot?

author: Fraser
author_rank: Super Contributor
timestamp: June 07, 2018, 01:18:31 pm
content: I have tended to work in the Monochrome and Iron palettes but I know that building surveyors often like to use Rainbow High Contrast. For me, RHC is too 'noisy' as I like to see subtle temperature gradients with plenty of detail. Monochrome remains the purist mode of operation as no colour palette interpretation is present to distract the user. That said, people have their personal preferences and you will likely try all the available palettes and have a favourite that you tend to use more often than the others. Some palettes like th e high contrast types attempt to provide the clearest possible indication of the temperature Delta T in a scene. Hence why building surveyors like these palettes as they easily highlight hot and cold spots. There is also the isotherm imaging mode of course.It is possible to add palettes to the Ex and Exx series cameras and some users create their own custom palette files to meet their needs and desires. There are official colour palettes that were intended for vet and other medical uses. You can have a White or Black hot palette in both the Ex and Exx cameras. It is just a different palette file after all. One inverse of the other.Fraser

author: eKretz
author_rank: Frequent Contributor
timestamp: June 07, 2018, 02:00:20 pm
content: I've noticed the same regarding the multiple color palettes. For some reason they seem too distracting. That is interesting regarding the user-defined palettes. Is that something that has to be added via the config files or is that possible within the camera menu?

author: Fraser
author_rank: Super Contributor
timestamp: June 07, 2018, 02:49:48 pm
content: On the FLIR cameras the palettes are loaded as additional individual palette files into the operating system. Details are contained in the E4 teardown thread. Forum members have also created palette creation utilities to make a custom palette file.Fraser

author: eKretz
author_rank: Frequent Contributor
timestamp: June 07, 2018, 05:06:21 pm
content: Thanks for the info. I'm still chewing through the teardown thread - it's something like 350 pages.

author: Fraser
author_rank: Super Contributor
timestamp: June 07, 2018, 06:43:17 pm
content: You can search keywords on the thread using Google rather than the less than great forum thread search tool.Fraser

author: eKretz
author_rank: Frequent Contributor
timestamp: June 07, 2018, 09:17:56 pm
content: Vielen dank! That did work much better.

author: eKretz
author_rank: Frequent Contributor
timestamp: June 08, 2018, 09:53:35 am
content: Also for anyone else who might be wondering: I just finished a firmware update to 2.23 and a pile of upgrades and there is an "invert palette" option in the menu now, so "Gray" can be either white hot or black hot with the press of a couple buttons.

author: Vipitis
author_rank: Frequent Contributor
timestamp: June 08, 2018, 11:02:10 am
content: My first replay seems to have vanished... So here is a copy from memory.I mainly use monochrome greyscale with linear scaling. It's he graetest for identifying objects. Especially when you got low resolution imagers like I am limit to right now. It's a great view to just use it as navigation in the night. It's often visuals that I wish to take a picture of in black and white analog negatives(but there is nothing that could work as LWIR photographic film as far as I know) - so switching between black-hot and white-hot is something I do very often. Monochrome also gives he best options for post processing when you don't got radiometric raw images like the .pngs Thermal Camera + creates. So you can apply custom fake color pallettes I post.I dislike iron. It's overused and the contrast in the upper range is missing. Inverted iron is great but rare.Mixed pallets like ironbow or alert are good to detect body heat and ironbow does agreat job outdoorss by splitting alive objects from inanimate objects an backgrounds.Rainbow is far better as the red between the yellow and white on the top end and therefore my go to for inspection, interior, exterior or medical. The green makes the divider between the yellow/red/white object and blue background. It's noise is reasonable.Anything high contrast like color wheel 6/12 is not usable with my noise an resolution. Maybe works for medical side by side... Like two hands and it directly shows a distinctive difference.Magma/Lava or Arctic are sometimes really great for interior inspection like windows/doors because the contrast just fits... So I sketch between those once untill I find the best one.I use artistic pallettes that I handcraft for some images, but I have yet to find a good workflow apply the same pallette to a greyscale image from ThermalCamera+ in post - other then doing the curves by hand. I really dislike the flir blurring and histogram scaling because it's so inconsistent.

author: eKretz
author_rank: Frequent Contributor
timestamp: June 08, 2018, 12:13:10 pm
content: Good info, thanks. I was quite happy to see the addition of the "invert palette" button after the upgrades on my E40. It does work on every palette also - I found inverted iron to be pretty good too, though it might confuse some folks, heh.

author: Bill W
author_rank: Super Contributor
timestamp: June 17, 2018, 05:00:21 pm
content: As Fraser notes the main problem with thermal camera images is that they tend to be quite noisy, whether fixed or moving. The human eye is quite good at averaging out 'brightness' noise but colour noise drives it crazy.So the main thing is to stay away from very harsh colour changes. That is what 'Iron' and several variations on blue->green->red achieve.Simple palette design can be done in the likes of ImageJ, but only for still imagery.Black hot is classic for military use, goes back to mono displays, and was supposed to be better with cold skies which made 'white hot' imagery get too bright in the interesting areas.White hot is more sensible for commercial / technical use including firefighting, with limited colour for indicating temperatures of interest. A lot of palettes seem to be useless padding though.Bill