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Services : Aerial Imagery Acquisition

Aerial Imagery Acquisition
The methods for capturing aerial photography have drastically evolved over the years.  Improvements in technology and the demand for a wider range of products have dramatically advanced the art and flexibility of aerial photography. The types of cameras and the diversity of the images they produce have changed substantially, enabling Triangle Aerial Surveys to offer a wider variety of features.

 

Film Photography

Film photography is still being generated from frame image cameras.  Panchromatic, color and infrared images can be captured, developed and digitized.
 


Digital Photography

In contrast to standard film photography, digital cameras capture images and store the data in a form readily accessible to computer systems. The enhanced remote sensing information provided by cutting-edge digital camera sensors is becoming the standard for aerial image acquisition:  The resultant raw imagery can be handled by image processing software without the need for time-consuming printing and scanning.

Modern digital cameras are equipped with an array of different sensors, enabling the cameras to capture multiple spectral bands at the same time.  This means that a single camera can capture panchromatic, color and near infrared imagery in a single pass over the target area.  For large aerial acquisition projects that require more than one type of image deliverable, these Multispectral cameras can be cost-effective. 

TAS is able to provide aerial photography in both film and digital formats.

 

Lidar

Lidar (Light Detection and Ranging) systems use near-infrared laser light to obtain accurate measurements of elevation.  An on-board Global Positioning System (GPS) lets the Lidar system know exactly where and when each laser was fired.  The beams of light are released in a wide swath towards the ground as the aircraft moves.  Measuring the time it takes for the beam of light to return to the aircraft allows the system to calculate the distance from the aircraft to the ground below.  The data is stored in a computer as X, Y and Z values.

The values obtained from Lidar systems are visualized as a point cloud for the purposes of mapping.  These data points are processed through a series of algorithms to remove inaccurate values and create a smoother surface.  Once the raw Lidar data is edited and cleaned the data points comprise a Digital Elevation Model (DEM).

Lidar data can also be used to generate a set of intensity images.  The intensity of the laser beam is recorded when it reflects from the ground and returns to the plane.  The picture created is useful for identifying the overall terrain, vegetation and bare-earth elevation.  Viewed stereoscopically, the intensity images can be used to collect planimetric detail and breaklines.  Combining breaklines and Lidar points into a Digital Terrain Model (DTM) allows accurate contours to be generated. 
 

 


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