Tetracam Multispectral Imaging Systems Overview

 

This article consists of a basic Overview of Tetracam Systems and a detailed Comparison between the ADC Micro and ADC Lite Systems. Overview Tetracam is the leading provider of multi-spectral cameras in the world.  All of our cameras are sensitive to visible and near-infrared light.  Because healthy plants reflect near-infrared light much better than unhealthy plants, the largest use of our systems is for agriculture.  Farmers all over the world use our systems as early warning systems for spotting plant threats and increasing crop yield.   We make two basic types of systems, ADCs and Micro-MCAs.  ADCs Camera models in our Agricultural Digital Camera or ADC family each consist of a single camera.  These are equipped with fixed filters that look at the same wavelengths that Landsat satellite systems view.  Just as scientists have used Landsat satellites for years to spot problems with crops or forests or coral reefs from space, our ADC systems can be used on the ground or in manned or unmanned aircraft to spot the same kinds of problems.  Our camera systems have become very popular lately because they are inexpensive and they are easy to fly over crops in comparatively inexpensive unmanned aircraft systems. They see greater detail than can be viewed from satellites and their views are never obscured by clouds. Each of our ADC models is designed for use in a specific venue:    Our ADC camera model is designed for hand-held use. Details about the ADC can be viewed on our web site at: http://www.tetracam.com/Products-ADC.htm   Our ADC Air is designed for use in manned aircraft. Details about the ADC Air can be viewed on our web site at http://www.tetracam.com/Products-ADC_Air.htm   Our ADC Lite and ADC Micro systems are designed for use in unmanned aircraft.   Details about the ADC Lite can be viewed on our web site at http://www.tetracam.com/Products-ADC_Lite.htm   Details about the ADC Micro can be viewed on our web site at http://www.tetracam.com/Products-ADC_Micro.htm   For a detailed comparison between the ADC Micro and ADC Lite systems, please see the write-up below.   Micro-MCAs   Miniture Multiple Camera Arrays are systems that consist of multiple cameras that are all aligned to view the same image.  The Micro-MCA4 consists of four aligned cameras.  The Micro-MCA6 consists of six aligned cameras and the Micro-MCA12 consists of twelve aligned cameras.    While ADC systems contain fixed broadband filters that match those carried in Landsat satellites, Micro-MCAs let users select any filter they wish to use within the sensor's range (450 nm to 1000 nm).  This allows Micro-MCA users to tell the difference between different types of plants, spot specific plant and soil conditions or specific compounds like a fertilizer or insecticide.  Users can spot any conditions at all that are identifiable by a unique spectral signature.   Details about our Micro-MCA systems can be viewed on our web site at http://www.tetracam.com/Products-Micro_MCA.htm     Software   PixelWrench2 software comes with every one of our cameras.  This software lets users move images captured on each camera's flash memory cards into their computer where the images can be manipulated, analyzed or converted to other standard file formats such as JPEG, PNG, BMP or TIFF.  PixelWrench2 lets users extract vegetation indices like NDVI or SAVI from captured images.  And it allows users to read the GPS data stored with the images that identifies the exact location where the images were captured.  This data enables users to use other vendors' mosaicking and geo-referencing software to stitch together the individual images they captured with Tetracam cameras.   Details about PixelWrench2 can be viewed on our web site at http://www.tetracam.com/Products_PixelWrench2.htm     Documentation and Training   Each of our cameras has its own user manual that can be downloaded off of the web site.  A hardcopy of the user manual is included with each camera.  PixelWrench2 contains a Help file embedded in the software that explains how each of its functions work.  We have a crop and application database on our web site that explains basic information about our technology and provides links to references on the web that show how multi-spectral technology has been used with specific crops or for other applications.   The Crop and Application database can be viewed on our web site at http://www.tetracam.com/MS%20Database.htm   We hold a training class three or four times a year near our headquarters in Los Angeles, California in the US.  The class uses lectures and hands-on lab and outdoor field exercises to teach about our hardware and software, how to interpret multi-spectral images, how to integrate our systems with manned and unmanned aircraft and how to stitch multi-spectral images together into geo-referenced image mosaics.     Comparison between Tetracam ADC Micro and the ADC Lite Systems   Both the ADC Micro and ADC Lite are specifically designed for use in UAVs. Physically, the ADC Micro fits into the palm of your hand.  It weighs 90 grams.  The ADC Lite is about double the size of the ADC Micro and weighs 200 grams.  Both systems are easy to mount into aircraft.  The ADC Lite contains four mounting points at the corners of its front side.   The ADC Micro mounts with three holes located on the system's base.  Both systems use the same sensor.  ADC sensors monitor red, green and infrared at the same wavelengths as Landsat satellites.  They are essentially equivalent to TM2, TM 3 and TM4.  Software that comes with every one of our multi-spectral imaging systems converts the captured images to CIF images or extracts vegetation indices such as NDVI or SAVI from these. These vegetation indices simplify differentiating healthy photosynthetically-active vegetation from areas in the image showing no vegetation or vegetation under stress. The ADC Micro and ADC Lite come with a 2 GB memory for holding approximately 600 to 900 images plus metadata such as GPS coordinates to correlate with each image. The ADC Lite uses a CF card for its memory.  The ADC Micro uses a 2 GB micro SD card for its memory.  ADC Lite images may be accessed via the camera's USB interface or by removing the card from the camera and plugging it into a computer.  ADC Micro images may be accessed by removing the SD card from the ADC Micro and plugging the card directly into a computer or using the included USB to SD card adapter to connect the card to a computer. The table shows maximum system capture intervals for full resolution images. The ADC Micro and ADC Lite are both able to store 8 and 10 bit images at sub-second speeds, if necessary, if their resolution is halved. Besides their size and weight, the major difference between the two systems is their optics and interface.  The ADC Lite comes with an 8.0 mm changeable C-mount lens.  The camera body has a CS Lens mount system with a C mount adapter so the ADC Lite may use thousands of lenses available from standard camera shops all over the world.  The ADC Micro comes with a fixed 8.43 mm lens. The ADC Lite is equipped with discrete Power, Trigger, RS232, USB and Video out connectors on the side of the unit.  The ADC Micro is equipped with a USB interface, external menu control buttons and a 15-pin Multi-IO connector that provides access to each of the trigger, RS232 and video functions through the individual wires or through a test and control box assembly provided with the system. In order to change ADC Lite menu configurations, users must connect the camera to a laptop running PixelWrench2 via its USB interface to gain access to system configuration menus.  ADC Micro users can access the menu through the USB interface or they can use external buttons on the camera or test box and view the menu via the video out connector on the Test box. Both systems run on 12 V DC power and consume about two watts.  The ADC Lite is tolerant of voltage inputs ranging from approximately 6 volts DC to 14.7 volts DC.  The ADC Micro can accept 6 volts DC up to 18V DC input, more than 3V higher than the ADC Lite. This makes it a better choice for UAVs running Lithium Polymer (LiPo) battery packs. Both systems are able to be triggered in the following ways: Shutter Release:  Both systems contain external shutter release buttons. When the button is depressed the camera captures a multi-spectral image Auto-Timer: The systems  may be configured via the system menus to capture images continuously at intervals specified by the user via the camera's system menus. External Remote Trigger: This is the most common trigger method used by UAVs for both cameras.  In the ADC Micro, a ground level signal is applied to this imput typically from the autopilot as the craft arrives at a waypoint pre-defined by the autopilot.  In the ADC Lite, closing the connection between the RING and the TIP on the included External Trigger Cable causes the camera to trigger when the autopilot arrives at a waypoint. USB Triggering:  The camera may be triggered through its USB interface. Optional GetShot software enables remote triggering under command of a linked computer. Optional SensorLink GPS waypoint triggering application enables camera triggering at pre-defined waypoints - a popular method used in manned aircraft.  Neither method is typically used aboard UAVs. RS-232 Triggering:  The camera may be commanded to trigger by receiving an <ESC> T command via its RS232 serial interface.  Due to the delays incumbent in a serial link, the RS232 link is more commonly used to transfer GPS position coordinates to the camera at camera trigger time. When the camera is connected to a GPS receiver via its RS232 link, the camera records the coordinates of the location at which each image is captured into its log file upon receiving any camera trigger command. The list price of both systems is the same $3795 USD plus shipping and handling.  Availability of these systems is about 2 to 4 weeks from the time the order is placed.