MIL-rated series high-speed cameras

The selection should be based on the required image format, frame rate and available illumination. The N-EM records 1,920 × 1,400 at 846 fps and 1,920 × 1,080 at 1,096 fps, making it suitable when Full HD analysis must exceed 1,000 fps. The Q-EM provides 2.90 MP at 500 fps and can reach 1,546 fps at 1,280 × 720. The S-EM records 1,280 × 1,024 at 500 fps and uses larger 14 μm pixels where light collection is a central consideration. Engineers should calculate the spatial resolution needed at the subject before selecting a model solely from its maximum frame rate.

All three cameras are identified for MIL-STD-810 environmental and MIL-STD-461 electromagnetic testing, but the complete installation must still be assessed separately. N-EM applies MIL-STD-461E and MIL-STD-810 methods covering altitude, high and low temperature, temperature shock, vibration, mechanical shock and humidity. Its mechanical shock figure is 150 g for 10 ms on all axes, with spikes up to 200 g, while Q-EM and S-EM are rated at 100 g for 15 ms on three axes. These values apply to the camera rather than automatically covering lenses, mounts, cables or external power equipment. Qualification planning should therefore include every installed component and the actual platform vibration spectrum.

Memory should be selected from the required resolution, frame rate, bit depth and duration surrounding the trigger event. N-EM provides four seconds with 8 GB or eight seconds with 16 GB when recording 1,920 × 1,080 at 1,000 fps. Q-EM provides approximately 1.8, 3.6 or 7.2 seconds at full resolution and 500 fps with 2.6, 5.2 or 10.4 GB respectively. S-EM provides approximately 2, 4, 8 or 16 seconds at full resolution and 500 fps across its four memory capacities. Reducing the region of interest or frame rate extends these durations, so test engineers should allow sufficient pre-trigger history as well as post-event recording time.

Hardware synchronisation and IRIG-B should be used when recordings must align with other cameras, sensors or range timing systems. Each model provides synchronisation, trigger, status and GPIO functions, while Gigabit Ethernet handles configuration, live viewing and data transfer. N-EM supports IRIG-B 122–127 AM and 002–007 DCLS for frame synchronisation and time stamping. Q-EM uses IRIG B 122 B2, while S-EM provides IRIG-B timing and a return connection on its I/O interface. For a multi-camera installation, the system design should define the timing master, cable delays, trigger polarity and required timestamp accuracy before wiring is finalised.

Lens selection must account for image-circle diameter, focal length, aperture control and the mechanical mount. N-EM uses a C-mount and can be fitted with EF- or F-mount adapters, including remote focus and aperture control for the EF option. Q-EM has an adjustable-back-focus C-mount, and a 1-inch lens is intended to cover its complete image area. S-EM also uses a C-mount, but its full 1,280 × 1,024 format requires a lens image circle larger than 1 inch; a 1-inch lens covers a reduced 800 × 600 format. Field of view and edge illumination should be verified with the intended resolution and enclosure window before procurement.

External power should remain the primary design basis unless the test requires temporary autonomous operation. N-EM accepts 10–36 V DC at 30 W and provides up to ten minutes of battery operation or memory backup. Q-EM accepts 24–36 V DC, consumes 14 W without the data link or 18 W with it, and provides a 30-minute internal battery with an optional two-hour pack. S-EM uses the same 24–36 V DC input range, consumes 10 or 15 W depending on data-link activity, and offers a three-hour extended pack. Vehicle and airborne installations should include voltage-transient protection, connector derating and enough reserve capacity for download or memory-backup activity after the event.

All three models use Gigabit Ethernet and separate camera-control connections, but the available connector arrangements differ. Standard N-EM connectivity includes a lockable RJ45 data port and a 14-pin I/O connector with trigger, armed, triggered, remote-on, synchronisation, strobe and IRIG-B functions. Its optional MIL backplane can combine Ethernet and discrete I/O in one MS27508E12F35PN connector or separate Ethernet and I/O through two connectors. Q-EM and S-EM use lockable RJ45 data ports and 14-pin LEMO or ODU I/O connector configurations. The selected arrangement should reflect available panel space, service access, cable separation requirements and the connector system already qualified for the platform.

Sensitivity and minimum exposure time determine how effectively the camera can freeze motion under the available lighting. N-EM is rated at ISO 10,000 monochrome and ISO 5,000 colour without gain, with exposure adjustable from 2 μs to one frame period. Q-EM provides ISO 2,000 monochrome and ISO 1,000 colour with a 2 μs minimum, while S-EM provides ISO 3,200 and ISO 1,600 respectively with a 1 μs minimum. Short exposures reduce motion blur but require more light, a wider aperture or increased gain. ISO values should be treated as a starting point because lens transmission, gain setting, colour filtration and scene reflectivity will affect the final exposure margin.