Pulsar have led New Zealand’s hunting and professional thermal imaging market for over a decade, with high quality and innovative products. Many of the features that we take for granted on a thermal imager were developed by Pulsar.
Their latest product line for 2023 includes the first of the XL class Lynred sensors, with a pixel resolution of 1024×768.
Sensor resolution is an important specification for cameras and thermal imagers alike. More pixels provides finer detail and the ability to increase magnification while maintaining a clear image. Larger sensors also increase field-of-view, which is very important, especially at night and in adverse conditions.
Size is not the only consideration though, the performance of each pixel and the sensor overall is also important. Pulsar chose sensors made by global leader’s Lynred, which meet stringent performance and durability standards. The 1024×768 sensor has a pixel pitch of 12µm and, according to the Lynred spec sheet, is qualified for thermal weapon use and conforms to MIL810-MIL883 standards for reliability.
Sensor resolution
Sensor resolution is determined by the quantity and size of the pixels that gather the image formed by the lens. The new Pulsar XL sensor has a total of 786,432 pixels whilst a 640×480 sensor has 307,200 pixels. This is huge increase of 255%, to put this into perspective, a 1024×768 sensor has a greater number of pixels than a 640×480 sensor by the equivalent of almost four and half 384×288 sensors.
The pixel pitch of a sensor relates to the size if each pixel in the array. Smaller pixels can form a more detailed image because the pixels are closer together. Due to the long wavelength of Long Wavelength Infrared (LWIR), pixels of 12 µm or 12 thousands of a millimeter, are the smallest pixel size that is possible before performance loss becomes an issue. In comparison, a good digital SLR camera which is optimumised to work with shorter wavelength visible light, has a pixel pitch of around 4µm-6µm.
The downside of small pixels is less light/ LWIR falling on each pixel. This lowers the sensitivity, also known as Net Equivalent Temperature Difference (NETD) of the sensor when compared to with larger pixels. The new Pulsar Merger LRF XL50 has an industry leading <40mK NETD with its Lynred 1024×768 / 12µm sensor. Beware of Chinese thermal manufactures that claim that their 12µm sensors deliver <25mK NETD. For instance, our tests with a PARD SA32-35 12µ <25mK indicate that this sensor is nowhere near 25mK NETD.
Applications
The Lynred 1024×768 / 12µm XL sensor is similar in physical size to their 640×480 / 17µm sensors. This is because the larger pixels take up more space. Therefore, Pulsar products with the XP designation may be fitted with the new XL sensor. More resolution and field-of-view will benefit recreational hunters and professional users alike. The future may see some interesting developments.
