 |
 |
 |
|
|
|
|
   |
|
|
How difficult is it to operate the CropCam, ground control station and image software? What does the CropCam image software do? What is the maximum wind it can fly in? What kind of landing surface is required? How much open area is required to land the CropCam? Does CropCam have video capabilities? Can I purchase the video option? Can the CropCam fly in the winter? What is the spatial resolution of the imagery acquired from CropCam? Are the images taken by CropCam georeferenced? How can the images taken for the CropCam be integrated into my GIS? What can be used for ground control in the georegistration process? Are CropCam images orthophotos? Can CropCam images be viewed stereoscopically? How does CropCam compare to satellite imagery? How does CropCam compare to traditional aircraft acquired imagery? Can CropCam acquire Near Infrared Imagery?
The CropCam is a radio controlled (RC) glider with elevators, rudder, ailerons and flaps controlled by the autopilot. For navigation, the autopilot is equipped with GPS for waypoint navigation. Included is ground control software and pre-programmed flights. The CropCam can be flown autonomous from launch to landing. Specifications Carry case The altitude can be adjusted to suit application and country regulations. CropCam has flown 400 feet to 2100 feet Above Ground Level (AGL). In Canada, Transport Canada has approved the CropCam to fly up to a maximum altitude of 2200 feet. Regulations vary throughout the world and potential users must consult with their regulatory authority. The CropCam is designed to work with the Pentax Optio models. Recommended Pentax Optio models For more camera information, visit the Pentax link at http://www.pentax.com/ The Pentax camera has an infrared sensor for the shutter. An infrared L.E.D. switch triggers the shutter through commands given by the autopilot. The camera fits in a universal camera box that attaches securely to the wing and held by elastics bands. The camera and camera box together weigh five ounces (145 grams). The camera box is designed to fit all recommended Pentax Optio models. The number of images depends on the altitude and acres you choose fly. Generally, the higher you fly the more acres you can cover. For example at 2100 feet:
If you have less acres, you could fly lower. In addition, the images are overlapped 50% to allow for use with third party software, such as PT-GUI, software to stitch images together. For more on working with images, see FAQ on GIS applications. It should takes approximately 30 minutes to set up your CropCam. Depending on the wind, to fly 640 acres at 2100 feet takes 23-27 minutes. To fly 160 acres at 2100 feet, it takes 10 -14 minutes. How difficult is it to operate the CropCam, ground control station and image software?The ideal skill set includes both RC and computer skills. Radio Control experience is crucial to the operation of the CropCam. If you do not have Radio Control experience we strongly recommend you acquire these skills to ensure success or must have a RC pilot as a safety pilot for all CropCam flights. For computer competency if you can configure your Windows operating system or install programs, you should have no problem following the CropCam Manual. RC skills are be an asset. We also offer 5 days of training. The CropCam Image Software combines a set of pictures from a digital camera and a datalog into a set of geo-referenced pictures. The CropCam image software rotates each image so that the top of the image is north and saves the rotated image in a sub-folder called Rotated. Each time the CropCam initializes and the GPS locks, the autopilot automatically starts recording a data log. Among other things, the datalog records the position of the CropCam throughout the flight. The CropCam software matches the images from the camera to the latitude/longitude /altitude of the CropCam when they were taken. Finally the CropCam image software allows you to export the images in a TIFF format with associated World files (.tfw) for use with GIS or agricultural software. Please note it does not stitch images together. RC Control RC Transmitter / Receiver The normal life of a CropCam should be 200 plus flights. However, we have a CropCam with over 250 flights that is still flying with only minor repairs to the airframe. From personal stories our users tell us the CropCam has survived encounters with a telephone wire, trees, rocks and a hard landing on a frozen field. We offer replacement airframes. For minor repairs and maintenance, the CropCam can be fixed with RC parts that can be purchased directly from a local hobby store or website. If you are not confident to do your own repairs, you can send it back to us for repair. 60 km/h. The CropCam can fly in winds up to 30 km/h. The calmer the days, the better your images will be. The CropCam is an RC airframe that requires grass, soft crops or dry mud. Hard surfaces such as stubble, trees and concrete are not suitable and cause damage to the fuselage. If CropCam lands in autopilot or Computer in Control (CIC), you need 100-150 meters. In autopilot, depending on the wind it will land normally within 25 metres from where it was launched. To land manually in RC or Pilot in Control (PIC) you need 75 meters. Does CropCam have video capabilities? Video is pulled directly off the Pentax camera and sent to an additional base receiver where the laptop and/or monitor can pickup the signal. The camera gives a 640x480 video image at 30 fps and the system has a usable range up to and beyond 1 mile. The transmitter is quite small and light, it adds maybe an ounce to the airplane, the power in can be taken from the autopilot LIPO, so no extra battery is needed. Power consumption is only 100 MA every 10 minutes. A simple Velcro attachment to the bottom of the wing is all that’s needed for mounting, a few more leads are used to attach to the camera and for power. It is quite handy in that you can view and record a video image, and then take a full size picture any time using the picture button in horizon when something good comes into view. See a fly over a farmyard. The black dropout is when the picture was taken at the waypoint. click here to download the video [WMV]
The additional items needed for video can be
purchased through a RC hobby store: For more on video systems see
Yes and snow is perfect for landing. With respect
to temperature the CropCam should not be flown in temperatures colder
than -20 celsius. Please note, CropCam can fly, but you may have problems
with the camera operating at -20 celsius. CropCam and GIS The spatial resolution of imagery acquired from the CropCam depends on the camera being used and the height of the platform above the terrain when the images are acquired.
Where SR(x) represents the spatial resolution of the imagery in that specific axis, S represents the physical size of the sensor (mm), which in a digital system is the Charged Coupled Device (CCD), H’ represents the flying height of the platform above the ground (m), f represents the focal length of the camera used (mm) and nP(x) represents the number of photosites present on the CCD for that axis. The imagery that comes out of the CropCam and the
software that is provided with the system are georeferenced by means
of world files that are generated for each image. These world files
define the coordinates of the upper left hand pixel, the rotation of
the image and the spatial resolution of the image. This world file is
calculated from the GPS coordinate of the plane which is the centre
of the image when taken and the pitch, roll and yaw of the aircraft.
These parameters are written to the planes log file and downloaded to
a text file upon completion of the flight. Although the imagery that comes out of the CropCam are not currently automatically georeferenced they can easily be implemented into a GIS. Currently for implementation into a GIS users are following this process:
This georeferenced imagery can then be loaded into
nearly every GIS and remote sensing, image processing software packages
including:
The process of determining and using ground control points to be using in the georegistration can be done by two methods:
The raw images acquired by CropCam are not orthophotos. Orthophotos are the result of the orthorectification process which involves standardizing photo scale across a photo which could have varied in the raw imagery due to variation in the topography of the terrain being acquired and the camera. Imagery from CropCam could be orthorecitified if the appropriate parameters like an accurate digital elevation model were present. To allow for stereoscopic coverage the CropCam flight
log can be adjusted to at least 50% end lap to ensure that the entire
area was acquired from two different perspectives. Endlap
refers to the amount of overlap that success images have, that is the
amount of one image that is overlapped by the next image acquired. There are a number of advantages that CropCam has over traditional satellite based image acquisition systems, including:
Most satellite based systems acquire multi or hyper spectral imagery beyond the visual portion of the electromagnetic spectrum. Currently CropCam only records reflected energy in the Red, Green and Blue or visible portion of the electromagnetic spectrum. CropCam is similar to traditional aircraft systems
but does offer some advantages. CropCam allows its users to preview
the imagery acquired and re-fly areas if needed. As CropCam can be packed
into a personal vehicle and driven to the area of interest the cost
per acre of land acquired is greatly reduced. CropCam is currently in the process of developing
a Near Infrared version of CropCam. Near infrared (NIR) imagery
is used for vegetation measurement due to the fact that plant cell structures
are very good and reflecting that portion of the electromagnetic spectrum,
approximately 750 - 1200 nanometre wavelengths. In contrast plants high
vegetation absorb a high of solar radiation in the visible portion of
the spectrum which they use as a source of energy in the photosynthesis
process amount of the red portion of the spectrum, approximately 630
- 690 nanometre wavelengths. This difference in the NIR reflection and
the red absorption is the basis the development of the Normalized Difference
Vegetation Index (NDVI). |
|
