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Top 8 things you need to know about a thermal imaging monocular

Jun 30, 2023 Mileseey tools

Thermal monoculars are highly favored due to their compact size, affordability, and popularity in the field of thermal optics. They offer a wide range of detection distances, starting from 90 meters and reaching beyond 1.2 kilometers. Whether you're interested in spotting game, enhancing security measures, exploring the outdoors, or hunting , a thermal monocular is an excellent and versatile tool suitable for anyone. This article serves to instill some of the important things of a thermal monocular in order to help people make the best decision of purchase and make the most use of their device.

1. What is a good thermal monocular?

TNV30 thermal monocular

A good thermal imaging monocular should have several key features. Firstly, it should offer a high resolution, preferably 320px and above, to provide detailed and clear images. The display should have a high refresh rate and contrast ratio for improved image quality. Advanced image processing technology, such as digital detail enhancement or image smoothing, can further enhance the overall image quality. The monocular should also have a good detection range, allowing it to detect heat signatures at a considerable distance. Higher sensitivity, measured in mK, enables accurate differentiation even between heat signatures of very small temperature differences.

The materials used should be of high quality to ensure durability, and a weather resistance rating of IPX4 or higher is desirable for protection against various weather conditions. The monocular should feature lenses with high refractive index or multi-coated lenses for clearer and sharper viewing. Lastly, a wide field of view will enable you to observe a larger area at a given distances.

2. How do thermal vision monocular work?

Thermal imaging

Thermal vision monoculars work by detecting and capturing infrared light, which is not visible to the human eye but can be felt as heat. Objects emit infrared radiation as a form of heat transfer, with higher temperatures producing more radiation. Inside a thermal monocular, microbolometers measure the temperature of each pixel on the sensor. The microbolometers then assign colors to represent different temperature levels, creating a visual image of the heat patterns in the scene. This allows us to see and interpret the variations in temperature across objects and their surroundings. The captured thermal data is processed and displayed on the camera screen, providing valuable insights into heat emissions and temperature differences.

3. How effective is thermal imaging monocular through heavy tree cover?

Thermal optics can be somewhat effective when used through heavy tree cover, but there are notable challenges to consider. The dense foliage of trees poses obstacles to thermal imaging, as trees not only absorb heat but also emit it. This makes it difficult to differentiate heat signatures behind the trees. Additionally, as the tree cover becomes thicker, it acts as a barrier, blocking the infrared radiation emitted by objects hidden behind it.

However, there are thermal imaging devices specifically designed for use in dense foliage environments that may be able to detect heat signatures through heavy tree cover. Additionally, employing a lower-resolution camera with a wider field of view could also enhance the chances of detecting heat signatures through dense tree cover. It is crucial to acknowledge that thermal imaging devices are not entirely infallible, and the results may vary depending on the device's specifications and the specific environmental conditions.

4. Can thermal imaging monocular see through walls and glasses?

Thermal optics cannot see through walls as depicted in movies. Walls are thick and insulated, blocking infrared radiation from the other side. When aimed at a wall, the thermal monocular detects the wall's own heat, not what's behind it. However, if there is a significant temperature difference caused by something within the wall, like water leakage, the device can sense it on the wall's surface. Glass and reflective materials like polished metal act as mirrors for infrared radiation, reflecting the temperatures of objects instead of allowing transmission through. When pointed at a window, a fun fact is that the device shows a thermal reflection of the user rather than what's on the other side of the glass.

5. How do I use a thermal monocular for security purposes?

Thermal imaging technology plays a pivotal role in bolstering security measures by effectively detecting intruders based on body heat, even in low-light or adverse weather conditions. Moreover, thermal imaging technology significantly contributes to security by minimizing nuisance alarms. Unlike visible cameras that can be triggered by movement caused by headlights, reflections, animals, or debris, thermal optics ignore such non-threatening factors. This reduces the occurrence of false alarms.

With advancements in technology, thermal infrared devices have become more affordable and versatile, offering continuous surveillance capabilities. They are capable of detecting fires, monitoring traffic flow, and performing non-invasive screenings for elevated body temperatures to identify potential illness or fever. This makes them invaluable tools in maintaining comprehensive security systems across various industries and applications.

6. Why are thermal imaging monocular expensive?

Thermal optics devices are expensive primarily due to specialized components and unique requirements. IR detectors, essential for detecting heat, are made from costly exotic materials like Indium Antimonide (InSb), Gallium Arsenide (GaAs), or Mercury Cadmium Telluride (HgCdTe), which increases production costs. Additionally, thermal lenses require distinct materials like germanium, which is expensive at around $1,500 per kilogram in its raw state. The use of cryogenic coolers to reduce noise in high-end devices adds further expense.

Moreover, achieving uniform temperature measurement poses a challenge, necessitating calibration and sophisticated interpreting algorithms. These factors, including the specialized components, unique lens materials, cooled sensors, and calibration requirements, contribute to the high price of thermal infrared devices. While advancements and economies of scale may eventually lower costs, these factors currently make thermal devices more expensive compared to visible light cameras.

 7. What are the differences of the color palettes the thermal monocular offers?

color palettes of thermal monocular


A thermal imaging monocular can provide users with a range of color modes, each offering distinct advantages for various scenarios. The  Black Hot and White Hot modes delivers high level of contrast. In areas with abundant vegetation, the Red Hot mode is particularly useful for quickly detecting heat sources. The  Rainbow mode is designed to highlight even the smallest temperature differences, enabling precise temperature identification. The Green Hot mode maintains higher details at low screen brightness.

 8. Does thermal imaging monocular work in daylight?

Thermal infrared devices are designed to capture infrared light emitted by objects, making them independent of visible light. This characteristic allows a thermal monocular to be used effectively in various lighting conditions, including daylight. Unlike traditional cameras, thermal vision monocular do not rely on visible light to produce images. Instead, they detect and measure the heat signatures of objects. This makes them particularly useful in applications such as industrial inspections, search and rescue operations, and security monitoring, where the ability to detect heat anomalies during daylight hours is crucial.

However, it is important to note that while thermal monocular can operate in daylight, the quality and clarity of the thermal images may be affected by factors such as the intensity of sunlight and the presence of strong heat sources. Therefore, proper interpretation and analysis of images captured during daylight hours may require careful consideration of these factors.

The Mileseey TNV30 handheld thermal monocular

TNV30 thermal monocular

The Mileseey TNV30 hand held thermal monocular is a versatile device designed for hunting and wildlife observation. It features a powerful 384x288 thermal sensor for detecting heat signatures up to 1,300 yards away. With an OLED display of 800x600 pixels, it delivers clear and detailed images. The monocular is constructed with a corrosion-resistant Mg-Al alloy and operates in temperatures from -13°F to 122°F. The TNV30 offers 1-8x magnification, built-in photo recording, a 16GB memory card, and a battery life of up to 15 hours, making it an ideal companion for outdoor activities.

Key features:

384×288 IR resolution

25mm F1.0 Germanium Lens with Adjustable Focus

Distance measurement

Capable of connecting to an external screen

built-in 16GB memory card

Overall 24x magnification

Detection range up to 1,300 yards

Mag-Al alloy housing

Wide range of operating temperature

Up to 15-hour battery runtime


Overall, thermal imaging monoculars offer a valuable and reliable means of detecting and interpreting heat signatures. By understanding their capabilities and limitations, users can harness the power of thermal imaging technology to enhance security, outdoor exploration, hunting, and various other applications.



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