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Multispectral camera systems
In recent years, multispectral camera systems have grown from solely scientific instruments to industrial applications. But what is their added value compared to conventional machine vision cameras?
The electromagnetic spectrum ranges from radio waves of wavelength λ>1m to gamma rays with a λ<10-12m. The portion of this spectrum that can be directly observed by human beings is incredibly small compared to this. The human visual system is only responsive to light with wavelengths from 400 to 700nm. It is this small spectral band, which defines how we see the world, and it is only logical that we tend to use image sensors that are responsive to the same wavelengths. The standard-practice in machine vision nowadays is to use the spectral range between 200nm (ultra violet) and 2000nm (infrared). Most applications use CCD or CMOS sensor based cameras that are responsive to wavelengths between 400nm (blue) and 1000nm (near infra red).
A grayscale sensor creates for each pixel a scalar value, which is a measure of the amount of light that falls on it. All color information is lost since it does not matter whether a blue light particle (a photon with λ=450nm ) or a red one (λ=650nm) hits the sensor.
The term multispectral is used when multiple colors or spectral bands are sampled separately. A consumer photo camera that captures color images is a simple example of a multispectral camera, but often the term multispectral is reserved for more advanced systems. As with any technology there is a large range in systems; this article aims to provide an overview of the most commonly used concepts of multispectral systems.
The complete content of the article can be found at our website.
Schiebel CAMCOPTER multispectral NVDI inspection
 Monitoring the soil composition of agricultural land is important for maximizing crop-yields. Carinthian Tech Research, Schiebel GmbH and Quest Innovations B.V. have developed a multi-spectral imaging system that is able to simultaneously capture three visible and two near infrared channels. The system was mounted on a Schiebel CAMCOPTER S-100 UAV for data acquisition. Results show that the system is able to classify Different land types and calculate vegetation indices.
Soil monitoring is important for maximizing crop-yields. Accurate and up-to-date maps of water status, nutrient deficiencies and pest infestation allow farmers to take rapid, targeted action that minimizes costs and environmental impact. Manual monitoring involves taking ground samples and estimating the soil water status at random locations. For large areas this is time consuming and cost intensive, furthermore, it gives only a sparse sampling of the area.
Recently Unmanned Aerial Vehicles (UAV's) have become much more widely used and economic advances in imaging and computation have also made spectral imaging techniques more affordable. By combining these technologies, remote sensing techniques, which were previously limited to satellite-based or military systems, can now be economically applied to make frequent and high resolution surveys of agricultural land.
The complete article can be found here.
SPIE Photonics West 2011
 As announced in the previous newsletter Quest Innovations BV will be present at the SPIE Photonics West show in San Francisco by the end of this month (22 - 27 January).
You are more than welcome to visit our booth to get a demonstration of our newest products. The main product on display is our Condor-1000 MS1-FV which uses a Foveon X3 sensor to capture three visible bands Red, Green and Blue.
Other products include the Condor-1000 MS3-RGB-618, a 3CDD color camera that creates images at a speed of 120+ fps and the Condor-1000 MS3-BNN-285 which uses three Sony ICX285 sensors to take high resolution images in the Visible and NIR spectrum. The brand new Architector Vision Suite shall also be showcased during this event.
We hope to welcome you at the Holland Pavilion, booth no. 4301.
Upcoming events
- SPIE Photonics West, 22 - 27 January 2011, San Francisco, California, USA
- SPIE Medical Imaging, 12 - 17 February 2011, Lake Buena Vista (Orlando), Florida, USA
- Fotonica Evenement, 29-30 March 2011, Nieuwegein, The Netherlands
- Vision & Robotics, 25-26 May 2011, Veldhoven, The Netherlands
- The Vision Show, 25-27 May 2011, Boston, Massachusetts, USA
- Health & Technology, 14-15 September 2011, Arnhem, The Netherlands
- VISION 2011, 8-10 November 2011, Stuttgart, Germany
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