Good thermal color palettes for B&W screens? - Page 1
Forum section: electronics / general

author: flyingfishfinger
author_rank: Contributor
timestamp: July 21, 2022, 09:09:53 pm
content: Hi,I have a Infiray P2 I'm using as a way to stream UVC thermal video (nice feature). I'm using a black and white TV screen for viewing the output though, and I'm wondering what color palette will "scale" best to a black and white screen.For example, if I use the actual black hot or white hot palette and display them, I get less thermal resolution than if I select the "rainbow" palette.I'm guessing that's because there are just more distinct colors available with the latter that can be displayed even when converted to B&W. However, it seems like the temperature-adjacent colors, while looking good on a color monitor, are too different from each other when viewed in black and white. The result is that as soon as the gain changes or objects of other temperatures are viewed, parts of the scene will "flip" from dark to light instead of getting lighter or darker, even if they didn't change much in temperature.Ideally it seems like I just need more "shades of grey", but I don't know if that can be achieved by just turning contrast and brightness knobs or if I need to define some other color palettes.Does anyone have suggestions of how this can be improved?R

author: Bill W
author_rank: Super Contributor
timestamp: July 22, 2022, 10:04:51 am
content: You could look at the ImageJ palettes, would be easy to test on a PC and you can make your own.Then just use paint etc to convert to greyscaleA pure B/W is likely to be 256 levels at most (8 bit) but can be just 64 (to suit 16 bit 5:6:5 LCD's and similar colour matrix IC's).Bill

author: Krist-win
author_rank: Contributor
timestamp: July 26, 2022, 12:59:42 am
content: Have you try the color bar，change the temperature measurement range，so the display color would bedifferent.

author: markb1980
author_rank: Regular Contributor
timestamp: November 26, 2022, 11:59:38 am
content: Quote from: flyingfishfinger on July 21, 2022, 09:09:53 pmI know that's a pretty old toppic and you have propably figured it out but maybe somone else will need the information also... Theironorironbow(yellow/violette) palette can be printed or viewed in black-and white very well. This palette was designed with black and white copies of a report in mind!

author: DaJMasta
author_rank: Super Contributor
timestamp: November 27, 2022, 07:47:16 am
content: I don't know if you have the option to, but you could try just throwing out the most significant bits of the data and mapping the 8 least significant bits (or maybe drop one or two lsb for noise and pick the rest). Basically, modern thermal cores should be outputting more than 8 bits of data - 14 bits is pretty standard, but for 24 bit color, for example, you really only have 256 greys to play with. Now more modern displays may give you 10 bits of color and then the same number of greys, but that's still quite a bit shy of the dynamic range of a thermal camera, so they scale the extra bits into different color channels, so we can better visualize the full dynamic range with our eyes that see more than just black and white.I've played around with some manual pixel depth configurations in some digital capture devices and you get a very neat banding effect somewhat similar to a rainbow palette when you look at 14 bit data in a mode looking at fewer bits, because you see the ramping up of the thermal gradient in the frame, and then it suddenly resets as those more significant but now hidden bits turn over. Not great for a normal looking image, but great for seeing the detail of the dynamic range in an image.