 ADS40 ALS50 DMC |
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Because a scanning process captures the imagery, forward lap is not required and control requirements are greatly reduced. A single lens captures the images and a trichroid filter separates the images into discrete bands. Thus, the ability to perform image classification (supervised and unsupervised) is far superior to any film-based or other CCD array systems. The ADS40 is based on the three-line-scanner principle where linear arrays on the focal plane capture reflectance data looking forwards, downwards, and backwards from the aircraft. The entire ground surface is imaged three times, which is far superior to the 50% triple coverage in typical film aerial photography. Additionally, the ADS40 simultaneously captures data from three panchromatic and four multispectral bands, avoiding the need to make a difficult choice between panchromatic, color, and false-color film. The ADS40 captures high resolution panchromatic and multispectral data together with position and attitude information to facilitate ground-processing. The absence of film errors combined with the tight integration of the inertial measurement unit (IMU), focal plate, and airborne global positioning system (GPS), greatly reduces ground control requirements, decreases pre-processing time, and increases accuracy. |
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The laser scanner measures the topography of the Earth's surface by acquiring large sets of ground surface XYZ coordinate triplets. These are computed using a laser range from the aircraft in combination with position and attitude data derived from airborne global positioning system (ABGPS) and inertial subsystems. The ALS50 is a high performance, robust solution for acquiring geospatial information. It provides users with digital surface models for a myriad of applications, including:
The LiDAR system consists of an ABGPS with attendant GPS base station(s) that ascertains the in-flight 3D position of the sensor; an inertial measurement unit (IMU) that delivers precise information about the attitude of the sensor, and the light-emitting scanning laser. LiDAR data are captured as the aircraft flies across a project area, emitting laser pulses with a high rapidity towards the ground. These points are reflected by the ground and/or objects upon it such as trees and buildings. For each pulse the elapsed time between the emitted and returning signals is measured enabling a slant distance to be computed. At the same time, the position and attitude of the aircraft are measured with airborne GPS and IMU sub-systems. During post-processing, these data are combined with the slant distance, together with information on atmospheric conditions, hardware characteristics, and other relevant parameters, to generate an XYZ coordinate triplet of a point on the ground. Our focus for DEM production is to achieve higher altitudes than existing commercial devices. This is accomplished using a high-powered laser with rapid repetition rates and a narrow pulse width capable of producing millions of points to provide a dense digital terrain model (DTM). LiDAR data can be acquired coincident with aerial photography as an efficient means to develop products with high information content. Using LiDAR, Gis Ground is able to produce 2' - 5' contours from as high as 8,000'. This far exceeds the capabilities of traditional photogrammetric techniques. |
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The DMC is unlike a film camera in that it uses eight individual lenses instead of a single lens. The lenses operate simultaneously and collect color imagery (red, green, and blue bands), color infrared (CIR), and black-and-white (panchromatic) imagery on charged coupled device (CCD) arrays. The panchromatic imagery and the color imagery are then combined to form a single high-resolution image. In fact, the sensor can capture imagery with a ground pixel resolution as high as 1.5 inches. The ability to capture infrared imagery has many practical applications. Since active vegetation reflects near-infrared radiation, imagery can be used to study the location, type, and condition of vegetation. A challenge with film-based solutions has been the capture of aerial imagery while using airborne GPS, as constellations are not always available and the flight must take place within a certain distance of a base-station. With the DMC, even if the global positioning system (GPS) signal is completely lost, flight conditions are severely turbulent, or light conditions are poor, high-quality metric imagery is assured. The DMC incorporates a Flight Management System that allows the aircraft to follow very precise flight lines even in the roughest of conditions. The imagery itself is captured in 12-bit per pixel radiometric resolution. Conventional film is captured as a single emulsion and separated into bands to create 8-bit pixels, meaning only 256 levels of color are available per band (three bands for natural color - red, green, and blue). With the DMC, 4,096 levels are available. Therefore, a great deal more can be done to control the contrast and brightness of images than with film. The result of using digital imagery versus film is increased efficiency in the overall production process as well as higher quality deliverables such as orthophotos. The consistency of image capture avoids many of the problems historically associated with film photography such as film scratches, dust, and Newton ring artifacts. In addition to the latest technology, our staff is continually being trained on the latest hardware and software. |
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The ADS40 represents a unique design in aerial imaging, using a pushbroom scanner to capture stereo panchromatic (black and white), true color, and false color-infrared (CIR) imagery simultaneously. Although we have acquired 4-inch imagery, the ADS40 fills a niche for 6-inch to 2-meter (ground sample distance) pixel resolution imagery. 
Gis Ground is recognized for it's high quality and quick turnaround LiDAR processing in the US, often completing projects for our competitors due to our experience, quality of work, and breadth of LiDAR editing knowledge. Our advantages stem from the use of our own technology both in hardware and software. 
The Z/I Imaging Corporation's Digital Mapping Camera (DMC) is a turnkey digital aerial camera system designed to support aerial photogrammetric missions demanding high-resolution and high geospatial positional accuracy. Designed from the ground up as a digital replacement for film-based photogrammetric mapping cameras, the DMC features breakthrough technologies enabling successful projects from small-scale mapping operations to precision, high-resolution corridor engineering projects.