Basic Parameters Introduction

NETD (mK Number) 

The term NETD stands for Noise Equivalent Temperature Difference, which refers to the thermal sensitivity and resolution of a thermal imaging camera. It directly reflects the quality of the camera's installed sensor. The lower the NETD value, the higher the clarity of the camera's image. NETD is measured in millikelvin (mK), with most devices from the HIKMICRO offering impressive values of ≤ 20 mK.

Thermal Resolution / Detector Size

The sensor serves as the foundation of a thermal imaging camera, playing a vital role in determining the overall performance of the system. Key parameters that define the sensor's capabilities include its resolution, measured by the sum of pixels, and pixel pitch. When it comes to resolution, a higher number of pixels directly translates to a superior image quality. The number of pixels per column, such as 384 × 288 pixels, provides a quantitative measure of resolution. Opting for a higher pixel count results in a sharper and more detailed display of the image.

Pixel Pitch

Pixel pitch refers to the distance between individual pixels on a screen or display, and it is measured in micrometers (μm). The term "picture element pitch" is used to describe this distance. Specifically, pixel pitch is measured from the center of one pixel to the center of the adjacent pixel, both horizontally and vertically. Depending on the direction of measurement, different values may be obtained. In general, a smaller pixel pitch indicates a more detailed image, as the distance between pixels is reduced.

Aperture / Focal Length / F-Number

The aperture is the main lens that focuses light into the focal point. The larger the aperture, the more light the system collects and the more details you can see.

Focal length is the distance between the point in space at which distant light is focused and the center of the aperture.

The f-number (e.g. F1.0) represents the ratio of the focal length to the objective lens diameter, indicating the field of view.

Field of View (Degree / m @100m)

The field of view is a crucial factor in selecting the right thermal device. Several key elements determine the field of view, including sensor size, basic magnification, and focal length. In general, devices with larger objective lenses have longer focal lengths, resulting in a smaller field of view, which is suitable for hunting in the open field. The devices with smaller focal lengths usually have a larger field of view which is suitable for hunting in forests because of the great overview. On the other hand, devices with smaller f-numbers offer higher information density and superior imaging performance. Additionally, larger sensors contribute to a larger field of view. Consider these factors when choosing a thermal device to ensure optimal field of view and overall performance.

Detection Range 

The detection range refers to the maximum distance at which an object can be detected as a heat source. Devices with a longer focal length offer a higher detection range, making them more suitable for open terrain. Conversely, thermal devices with smaller lenses are better suited for forest areas. In these settings, a wider field of view, achieved through lower magnification, is advantageous. The detection range is typically determined using the Johnson criteria, which considers a target size of an upright standing man measuring 1.8 × 0.5 meters. However, it's important to note that this calculation is primarily theoretical and does not take factors like image quality into account.

Basic Magnification / Digital Zoom

The basic magnification indicates the level of optical magnification when viewing the device's display. This magnification is customized for each device, depending on its type. Digital zoom refers to the act of enlarging the image on the screen. However, the perceived imaging performance can be affected by factors such as the device's resolution and the chosen zoom level.

Frame Rate

The frame rate determines the number of image changes a device can achieve per second, measured in Hertz (Hz). The higher the frame rate, the better the image will be for viewing while in motion. To ensure a seamless and flicker-free display of moving objects, a minimum frame rate of 50 Hz is recommended. Currently, thermal imaging cameras successfully meet this standard.

CMOS, Lux, Resolution

CMOS is the abbreviation for "complementary metal-oxide semiconductor". In other words, a complementary metal-oxide semiconductor. This sensor absorbs photons, i.e. light, and converts them into an electrical signal. In the realm of digital night vision devices, these sensors vary in their light sensitivity (lux) and their size (resolution). To put it into perspective, 0.1 lux is equivalent to the brightness of a full moon, while 0.0001 lux represents the lighting conditions of a starry night.

IR Wavelength (850nm / 940nm)

By incorporating an internal or external IR illuminator, night vision devices can greatly enhance their range. Opting for emitters with a light color of 850 nm significantly boosts brightness, although they may occasionally be detected by well-eyed game species. On the other hand, 940 nm emitters emit a less luminous light color, but are completely game-safe and go unnoticed by well-eyed game species.

*Before purchasing any thermal or digital day & night vision device, please make sure you adhere to the local ledislation and only use it when it is allowed. Our ambassadors come from various countries and travel a lot, which allows them to test different devices. We do not encourage or support the illegal use of our devices in any events.