Thermal Camera 'Color' / Palette Tutorial

By: Ethan Ace, Published on Oct 31, 2013

When many think of thermal cameras, they visualize their use in movies and TV, with a multi-colored science fiction color scheme, familiar to anyone who's seen 1987's Predator:

Predator's thermal vision

Indeed, some manufacturers offer more than a dozen palette options in their cameras. The question is: are these color schemes actually useful in surveillance applications? In order to show the differences between these options, we examine the typical palettes used in thermal surveillance, and potential for lesser-used palettes.

White Hot/Black Hot

The most common palette used in thermal cameras, generally the default setting, is "white hot", in which warm objects appear as lighter shades of grey, and cooler objects appear darker. "Black hot" is an inverted version of this scheme, still greyscale, with warm objects on the black end of the scale. This scheme is available in most thermal camera models. These two schemes may also be referred to as simply "greyscale" and "inverted."

This image shows our subject in the same scene using white hot and black hot palettes (click for larger version):

White hot vs. black hot

And again, at approximately 620', very little difference in detail can be seen.

White hot vs. Black Hot, 620'

These two palettes essentially show the same amount of detail, with neither truly besting the other. However, we see two key factors which affect the decision of which to use:

Get Notified of Video Surveillance Breaking News
Get Notified of Video Surveillance Breaking News

  • Monitor setup: Many users' monitors are set up to maximize brightness, with contrast being a secondary concern. Because of this, differentiation between shades of grey on the brighter end of the greyscale may be more difficult than distinguishing between dark shades. Thus, black hot images may be easier to monitor than white hot, with small subjects easier to make out against a lighter background. The effects of this will vary depending on the monitor and individual user, and likely may be compensated for simply by lowering monitor contrast and brightness to prevent whites from running too "hot."
  • Scene type: In many scenes, operators are more accustomed to looking for dark subjects against lighter backgrounds. Intruders in desert settings, open fields, commercial offices, etc., are all generally darker than their surroundings. Because of this, black hot may simply seem more "natural", and be easier to adjust to than white hot images. In other areas, such when monitoring marine vessels against water, or vehicles against a road or parking lot, the object is often brighter than the background. Operators used to these scenes may find white hot easier to monitor.

Ice and Fire

Some manufacturers offer a color mode called "ice and fire" which may be useful where other color modes are not. Essentially, this mode is the same as white hot, but instead of displaying the hottest object in the scene as white, red is used, and blue is used for the coolest. In theory, this could serve to increase visibility, since warm red objects against a greyscale background should be easier to spot than brighter shades of grey/white. However, in practice, hot objects to not always display as red, and cool objects do not always display as blue.

For example, in this image, our subject was by far the warmest object in the scene. The outside temperature was around 35° F, and the SUV had not been moved from this spot during the day, making it quite cool. Additionally, he is clearly visible and prominent in the FOV. However, the camera at no point displayed any part of him as red while in ice and fire mode:

Ice and Fire

This is not unique to one manufacturer of camera, either. In other tests, warm objects have failed to display as anything other than greyscale on multiple manufacturers' cameras. If ice and fire were configurable, with users able to adjust what objects triggered as red, we believe it would be a truly useful color mode for thermal surveillance, but this is not currently the case.

Color Modes

In security, the main purpose of thermal cameras is simply detection, since fewer details are provided than when using visible cameras. In other applications, however, detecting and displaying minute variations in temperature may be desired. In these cases, colored palettes are far more common, since the full spectrum of color may more easily display a wide variety of temperatures than when using greyscale images. For security purposes, colored palettes may quickly become tiresome for operators to monitor, and thus may actually obscure detail across a larger field of view.

This image shows some examples of colored palettes compared to white hot and black hot images in the same scene (click for larger version):

Color palette comparison


For surveillance purposes, we see white hot, black hot, and ice and fire (with qualification) as the only viable palettes. We have seen no advantage to using colored palettes when using thermal cameras, and potentially some decrease in visibility and increase in operator fatigue. For those choosing between white or black hot, much of the decision comes down to operator preference, with monitor setup having modest impact. For those using cameras which support ice and fire mode, we believe it is worth testing in the individual scene. If it does perform, the displaying of subjects as red against the grey background may aid in detection. At worst, if it does not perform reliably, this mode is will be no different than using standard white hot mode, with little downside.

Comments (7) : PRO Members only. Login. or Join.

Related Reports

Milestone Machine Learning Camera Auto-Setting Examined on Mar 13, 2019
Milestone wants to improve image quality using Machine Learning to solve the problem of "a camera doesn't know what it is being used for",...
Startup Spectral Edge RGB+IR Claims "Unique Low Light Performance Tech" on Apr 03, 2019
This UK startup, born out of university research, is boldly proclaiming that they deliver "Unique low light performance tech for video surveillance...
False Verkada 'Unrivaled' Low Light Performance Claim Removed on Jun 12, 2019
Verkada falsely claimed that it delivered 'UNRIVALED LOW LIGHT PERFORMANCE' until IPVM questioned. In fact, Verkada's low light performance is...
Axis Live Privacy Shield Analytics Tested on Jun 25, 2019
Privacy is becoming a bigger factor in video surveillance, driven both by increased public awareness and by GDPR. Now, Axis has released Live...
Lens Iris Tutorial on Aug 08, 2019
Cameras, like humans, have irises, controlling the light which hits the imager and impacting image details. However, cameras have multiple types of...
Lasers Impact on Surveillance Cameras Tested on Sep 25, 2019
Hong Kong protests have brought global attention to video surveillance and the ongoing attempts of protesters to disable or undermine those cameras...
Biggest Low Light Problems 2019 on Nov 08, 2019
Over 150 integrators responded to our survey question: "What are the biggest problems you face getting good low-light images?" Inside, we share...
Hidden Camera Detectors Tested on Nov 18, 2019
Hidden cameras are a growing problem as cameras become smaller, cheaper and easier to access. However, some companies claim to be able to detect...
Budget Covert Cameras Tested on Nov 26, 2019
Covert cameras under $100 are widely available online but are they any good? To see how these models really work in the real world, we bought...
IPVM Opens 12,000 Sqft Testing Facility on Dec 16, 2019
IPVM is proud to announce the opening of the world's first video surveillance testing facility that will allow us to significantly expand our...

Most Recent Industry Reports

Verkada Paying $100 For Referrals Just To Demo on Jan 22, 2020
Some companies pay for referrals when the referral becomes a customer. Verkada is taking it to the next level - paying $100 referrals fees simply...
Camera Analytics Shootout 2020 - Avigilon, Axis, Bosch, Dahua, Hanwha, Hikvision, Uniview, Vivotek on Jan 22, 2020
Analytics are hot again, thanks to a slew of AI-powered cameras, but whose analytics really work? And how do these new smart cameras compare to top...
Intersec 2020 Final Show Report on Jan 21, 2020
IPVM spent all 3 days at the Intersec 2020 show interviewing various companies and finding key trends. We cover: Middle East Enterprise...
Vehicle & Long Range Access Reader Tutorial on Jan 21, 2020
One of the classic challenges for access control are parking lots and garages, where the user's credential is far from the reader. With modern...
Clearview AI Alarm - NY Times Report Says "Might End Privacy" on Jan 20, 2020
Over the weekend, the NY Times released a report titled "The Secretive Company That Might End Privacy as We Know It" about a company named...
Favorite Camera Manufacturers 2020 on Jan 20, 2020
The past 2 years of US bans and sanctions have shaken the video surveillance industry but what impact would this have on integrators' favorite...
"Severely Impacted" Mercury Security 2020 Leap Year Firmware Issue on Jan 17, 2020
One of the largest access controller manufacturers has a big problem: February 29th. Mercury Security, owned by HID, is alerting partners of the...
Apple Acquires, Loss For The Industry on Jan 16, 2020
Apple has acquired for $200 million, reports GeekWire. This is a loss for the video surveillance industry. stunned the industry...
Installation Course January 2020 - Last Chance on Jan 16, 2020
Thursday, January 16th is your last chance to register for the Winter 2020 Video Surveillance Installation Course. This is a unique installation...
Halo Smart Vape Detector Tested on Jan 16, 2020
The Halo Smart Sensor claims to detect vaping, including popular brand Juul and even THC vapes. But how well does it work in real world...