TrueIR Thermal Imager U5855A

Quick overview

Reap the benefits of a high resolution thermal imager that fits within your available budget

Extended Warranty

(to learn more click on the link above)


With the Fine Resolution capability, you can achieve effective resolution of 320 x 240 pixels from a 160 x 120 pixels detector – four times more resolution, four times more details.

  • Four times more pixels with Fine Resolution capability
  • View finer object details with 4x digital zoom
  • Quick access buttons to easily change settings or functions
  • Long product warranty – 3 years
  • Ergonomically designed with evenly distributed weight
  • In-camera monitoring for temperature trending
  • Ability to focus on objects, as close as 10 cm away

Predictive maintenance on electrical systems

Predictive maintenance on electromechanical systems

Get more details with Fine Resolution

Fine Resolution is a technology that restores the details originally inherent to the object while enhancing the resolution, at the same time minimizing fuzziness and noise. It is accomplished by performing sophisticated calculations on continuous multi-frames of the image – evaluated for misalignment caused mainly by hand tremor. The firmware then detects and corrects the information between images through one feature pixel.

With Fine Resolution,

  • Get an effective 320 x 240 pixels of radiometric JPEG IR image which is clearer and sharper
  • See fine details on objects as close as 10cm, especially when measuring temperature on small components which are close to each other.
  • With 4x digital zoom, magnify a thermal image of a far-away objects quickly to identify anomalies and to reveal even finer details.
  • These are essential for industrial, building inspection, electronics, as well as medical research.

              Figure 1. Samples of IR images

1. Torch light
2. Laser pointer
3. Visible image camera
4. Infrared (IR) image camera lens
(with shutter)
5. Focus adjustment ring
6. Camera trigger key
7. DC power inlet
8. Video out port
9. USB mini-B port
10. SD memory card slot
11. Adjustable hand strap (for right-handed or left-handed use)
12. Quick access buttons
13. Large 3.5” color LCD display

Perform more in-camera measurements and analysis

Capture thermal images effectively with its intuitive and easy to use tools:

  • Configurable quick access buttons that are able to change functions based on user preference.
  • Monitor temperature trends over time for quality checks when monitoring process parameters in industrial plant automation
  • Perform analysis using its extensive range of measurement tools.
  • Coupled with the U5855A’s high sensitivity of 0.07 °C, it can detect the slightest temperature difference to provide more accurate temperature readings.

Figure 2

Center spot, min, and max tracking three moveable spots

Figure 3

Three moveableboxes with statistics

Figure 4

Delta temperature

Ergonomically designed for comfort

The ergonomically built TrueIR thermal imager is designed to let you carry out daily tasks comfortably. With its evenly distributed weight of only 746 grams and good stability, it fits comfortably in your palm without straining your hands, even when used over a long period of time. With a stable grip, it allows you to single-handedly capture more images and to work more efficiently.

Figure 5. Ergonomically designed to have distributed weight. It can even stand on its own! Figure 6. Good grip with belt support

TrueIR Analysis and Reporting Tool

Import, analyze, edit and present your thermal images to your clients swiftly with TrueIR analysis and reporting tool. With this PC software, you could change color settings and corrective parameters, add color alarm, or pick and choose any of the six measurement analysis tools or diagrams to help you present your findings to your customers clearly.

Also, generate reports quickly with the help of ready templates and then customize them accordingly based on your clients’ requirements.

Figure 7. TrueIR Analysis and Reporting Tools GUI


  • Change color settings and corrective parameters, like emissivity, ambient temperature, atmospheric temperature, and more
  • Set color alarm
  • Choose between six measurement analysis tools or diagrams like spot, line, line profile, box, histogram and delta temperature
  • Capable to display thermal image, visual image, thermal-visual side-by-side, or fusion images as well as its associated photo or note tags
  • Create reports based on available templates and then customize them to suit your client’ needs
  • Generate reports in Microsoft Words or PDF
  • Eleven local languages to choose from - English, Spanish, Italian, French, German, Portuguese, simplified Chinese, traditional Chinese, Japanese, Korean and Russian

Download for free from

Figure 8. Sample of measurement analysis diagrams

Basic Performance


Measurement Range

-20° ~ 350°C

Range 1: -20° to 120°C

Range 2: 0° to 350°C

Thermal Sensitivity

Range 1: 0.07°C (at 30°C)

Range 2: 0.1°C (at 30°C)

Accuracy ±2 °C or ±2% (whichever is greater)
Detector Type Uncooled Focal Plane Array (a-Si)
Detector Resolution 160 x 120
Fine Resolution 320 x 240 (IR pixels)
Spectral Range 8 to 14µm
Frame Rate 9Hz
Field of View (FOV) 28° (H) x 21° (V)
Spatial Resolution (IFOV)

Fine Resolution OFF: 3.1mRad

Fine Resolution ON: 2.1mRad

Focal Resolution 10cm to infinity
Focus mechanism Manual focus

Image Processing and Enhancement

Correction Parameters Emissivity, reflected temperature, object distance, ambient temperature, humidity, transmissivity
Emissivity Correction 0.1 to 1.0 Predefined emissivity table
Digital Zoom Zoom ratio: 4x continous
Color Palette Rainbow, iris, hot iron, gray, inverted gray
Camera Mode IR image, visible image, picture in picture, blend

Measurements and Alarm

Measurements Center spot, 3x moveable spots, max/min tracking, delta temperature, 3x moveable boxes, (with min/max/avg)
Color Alarm

High/low temperature in all areas

Alarm zones: Above/below/inside/outside

1. Minimum distance with accuracy, 10cm to 50cm: ±4°C or ±4%

Supplemental Characteristics

Parameter Characteristic
Storage device Supports up to 32 GB SDHC memory card with class 4 and above
Image format IR image: Radiometric JPEG
Visible image: JPEG
State storage memory Three user-configurable stored states
Tagging/annotation 3 photo tags, note tag, note tag from template (downloadable from the Keysight Web site)
I/O USB 2.0 mass storage
NTSC/PAL via video RCA cable
Language English, French, German, Italian, Japanese, Korean, Portuguese, Russian, Spanish, Simplified Chinese, Traditional Chinese
Built-in quick start tutorial Available

Product Characteristics

Product Characteristics
Power Supply Power adapter Line voltage range: 50/60 Hz, 100-240 VAC (Auto/Universal voltafe), 1.2A
MAINS supply voltage fluctuations not to exceed ±10% of the nomial voltage
Output Voltage: 12VDC, 3 A
Installation Category I ( Isolated ELV supply source - connected to MAINS through an AC/DC power adapter)
Battery Li-Ion rechargeable battery, 7.4 VDC, 2500 mAh
Operating time: 4 hours
Display 3.5" TFT
Visible Camera 3.1 MP
Built-in led torch Available
Laser pointer Class 2
Warm-up time 2 minutes
Operating Environment Temperature  -15°C to 50°C
Humidity 50% RH to 95% RH at 40°C
Storage compliance Temperature -40°C to 70°C
Humidity 95% RH at 40°C
Altitude Up to 2000m
Pollution degree 2
Safety Compliance Laser safety: IEC 60825-1:2001 / EN 60825-1:2001 (Laser Class 2)
IEC 61010-1:2010 / EN 61010-1:2010
EMC Compliance IEC 61326-1:2005 / EN 61326-1:2006 • CISPR11:2003 / EN55011:2007, Group 1 Class A
Canada: ICES / NMB-001: Issue 4, June 2006
Australia / New Zealand : AS/NZS CISPR 11:2004
Shock Tested to IEC 60068-2-27 Ed. 3.0
Vibration Tested to IEC 60068-2-6
Drop Test 2m
Protection Class 2
IP Rating IP54
Dimensions (W x H x D) 95 x 250 x 85 mm
Weight 0.746 kg (with battery)

Refer to

3 years for the product

3 months for the standard accessories unless otherwise specified

Calibration cycle 1 year

Standard Shipped Accessories

Power Adapter with power cord

Rechargeable Li-Ion battery

SD card

Video RCA to RCA interface cable, 2m

USB Standard-A to Mini-B interface, 1m

Rugged, hard carrying case

Quick start guide

Certificate of calibration

Optional Accessories & Spares


Power adapter (with power cord)


Rechargeable Li-Ion battery


External battery charger (2-bay)


Video RCA to RCA interface cable, 2 m


USB Standard-A to Mini Type-B interface cable, 1 m


Rugged carrying case, hard


Hand strap, Adjustable for right-handed and left-handed use


We also recommend

Additional information

Manufacturer: Keysight Technologies