Aerial imaging can mean a lot of things, from reconnaissance satellites to foliage imagery from Low Earth Orbit (LEO) high-spectral imagers.

Our version is a lot closer to the subject and much more useful in protecting, observing and enabling a business like commercial photography.

There are many uses for low-altitude aerial imaging. These include:
     • Aerial Surveillance
     • Aerial Photography for commercial purposes
     • Aerial Photography for research, archaeology, geology and global warming studies
     • Oblique aerials for land planning and development
     • Medium-altitude imagery of the atmosphere
     • Traffic management
     • Accident investigation
     • Crowd control and management
     • Roof inspections
     • Construction site monitoring
     • Environmental clean up site progress monitoring

There are also many different methods and technologies for aerial imaging. Individually most are only effective for specific requirements. What realtor really needs a frontal photo of a property in the thermal spectrum? How much value is a digital SLR up on a balloon to a security detail on the ground? The point is, Aerial Products’ has a lot of capabilities and we strive to match our systems to customer needs. Sometimes there isn’t a match, when that happens the customer is the first to know.

All of our methods are based on lighter-than-air balloons and pneumatic masts. For the balloons we use Helium in all cases. As a Nobel gas Helium is as safe as oxygen. Further, all of our balloons are made of premium polyurethane(TPU) which is highly effective at retaining the very small Helium molecule.

When discussing an aerial imaging project the first thing we do is determine what detector is suitable. A detector is like a camera but may not have on-board data storage and may see things that are not visible to the naked eye, which is why we call them detectors instead of just cameras. As the realtor and security detail examples illustrate, one size doesn’t fit all when it comes to detectors. The same is true for the means of getting data from the detector down to the ground. In some cases we transmit low-quality live video of what the detector sees. This is the method for aerial photography. In other cases we use a high-data rate digital transmission to show 16 million pixels every third of a second. This method is used for aerial surveillance.

Our transmission methods are as varied as the uses for aerial imaging. These include:
     • Line transmission through a “smart” tether, analog or digital signal, including Kevlar reinforced fiber optic
     • Line transmission using an ancillary data-only line attached to the tether, analog or digital using twisted-pair
     • Wireless analog transmission, where video is sent and received similar to a TV signal
     • Wireless digital transmission, where video can be sent as packets of data or as modulated signals similar to the new digital TV standards

Like the detector, we match the appropriate data transmission method with the customer’s requirements. In one recent project, due to frequency magnetic concerns, we employed four forms of digital transmission in the same solution. This proved to be important since the customer’s experiment was affected by the high-powered radio, one form of line transmission was affected by ship’s power, and the remaining two provided the data rates required for the mission. We can design nearly anything to make our customer’s successful.

The final component to aerial imaging is the means of getting the payload in the air and retrieving it. There are options ranging from plastic cord winders and manual winches to electric-hydraulic winches with line levelers. These can operate from generators, line power and batteries. Generally we recommend the approach based on the size of the balloon, which is determined by the weight of the payload.

As a recap, with aerial imaging there are multiple facets to a system:
     • The detector used to see the subject or experiment
     • The transmission method for getting the detector’s image to the operator
     • The balloon used to carry the detector
     • The launcher used to manage the launch and recovery of the balloon

Getting back to the aerial sensor, detector or camera, light needs to bounce off of the subject for a visible light detector to work, and energy in the form of heat needs to be emitted for a thermal sensor to work. Energy, in the form of light, is the key; it is either emitted or reflected and wavelength as measured in microns is how devices are categorized.

The next main point to understand is that visible light is cheap to capture, thermal energy is expensive to capture. As you move from visible light wavelengths toward the infrared spectrum of thermal imaging, the cost increases exponentially. The inverse rule is true for resolution, sensors for visible light can be high resolution, up to 16 mega pixels, sensors for thermal imaging are commonly at 300,000 pixels or less.

So what are these detectors used for? From a practical standpoint, visible light sensors are great for commercial photography and in many cases for surveillance. Thermal sensors are good for no light conditions like border surveillance and for energy loss applications like roofing inspections. Wavelengths are as varied as people. You can start at one end of the spectrum, visible light, and move toward the other end, thermal, in infinitely defined steps.

Let’s break it down to three main wavelengths, their equivalent detectors and how they are best used:
1. Visible light
     • Photography
     • Daytime surveillance
2. Near-infrared
     • Archeology dig studies
     • Geological observations
     • Surveillance in low-light and no-light conditions (light amplification with IR illuminators)
3. Thermal-infrared
     • No light surveillance (borders, combat theaters of operation)
     • Energy loss detection and inspection (buildings, experiments)

To put this in context, the Aerial Products’ aerial imaging systems are grouped in the same fashion as the main wavelengths.
     • Commercial photography systems are visible light
     • LTAS100 is visible light and infrared augmented illumination (low LUX)
     • LTAS 200 has a visible light detector and a separate thermal detector (on separate gimbal)
     • LTAS 300 has a visible light detector and a thermal detector (on the same gimbal)