MWLW140 Multi Aperture
The Multi-Aperture infrared seeker shown in the photograph has two spectral bands: MWIR for detecting very hot targets; LWIR for detecting colder targets. The sensor and electronics were developed by DRS to enable true simultaneous dual band capture without the need to dither back and forth between bands. Simultaneous capture is especially important for image high speed events such as explosions. The multiple apertures of the optical system enable wide angle imaging across a very wide spectral bandwidth. The seeker’s performance characteristics are listed below:
• FOV: 140 deg with 2FtanΘ/2 mapping function
• Focal Length; F/#: 7.033 mm; F/3
• MWIR Spectral Band: 3.6 – 5.20 µm across 860 x 480 pixels
• LWIR Spectral Band: 7.8 – 9.65 µm across 860 x 480 pixels
The 2FtanΘ/2 mapping function is a compromise between oversampling at the periphery (wasting pixels) and limiting distortion, which can be corrected in software. The video snaps demonstrate the utility of the two spectral bands.
In the image of lab at night with cold drink next to hot soldering iron on table (below, right) structural beams are still hot, lights are hot. Solar tube skylights are cold. Both bands capture hot and cold equally well, but MW image on left is slightly sharper than LW image on the right, which also shows defective pixels in bottom left sector.
Below is the day image showing cold car on left appearing black in MW (left) and clouds appearing white in LW (right) and the night image showing hot car exhaust in MW (left) and brighter mountains in LW (right).
And here is the demonstration of the stitching and warping.
