Conventional night vision goggles all use image intensification (I2) tube technology that multiplies ambient, visible, and near-infrared light several thousands of times, allowing a user to see and operate in very-low-light conditions. One shortcoming of I2 tube night vision devices is that they cannot generate an image as a video signal that can be displayed on a monitor or transmitted externally. Further, the devices are sensitive to too much light, which can over-saturate the I2 tube and prevent the user from seeing any scene detail. This problem is called “blooming” or a “halo effect.” What is needed is an alternative imaging device that utilizes wavelengths of the electromagnetic (EM) spectrum currently unused in military environments.
Such a device was developed that operates as a direct-view, compact, shortwave infrared (SWIR) viewer-detector array, and is sensitive to the visible, near-IR, and SWIR regions.
An atmospheric phenomenon called night sky radiance emits five to seven times more illumination than starlight — nearly all of it in the SWIR wavelengths. Thus, with a SWIR camera and this night radiance — often called night-glow — it is possible to see objects with great clarity on moonless nights. This allows more photonic radiation to be used to create an image. In addition, SWIR illumination can be used to aid the sensitivity of the SWIR device.
Photonic energy from a scene enters the objective lens of the device and is focused onto the SWIR imaging detector. The detector's electronics create a video signal of the scene and provide the video signal to the display electronics. The display electronics create an image from the signal and present a visible image on the display panel.