Abstract:The use of consumer digital cameras or webcams to characterize and monitor different features has become prevalent in various domains, especially in environmental applications. Despite some promising results, such digital camera systems generally suffer from signal aberrations due to the on-board image processing systems and thus offer limited quantitative data acquisition capability. The objective of this study was to test a series of radiometric corrections having the potential to reduce radiometric distorti… Show more
“…Digital photography uses either silicon-based charge-coupled detectors or complementary metal-oxide-semiconductors, both of which have a spectral sensitivity from about 350 nm to about 1,100 nm wavelength [18,19]. Most digital cameras use a Bayer pattern array of filters to obtain red, green and blue bands for a digital image [18,19]; however, the chemical basis for making these filters is proprietary and there is variation in filter spectral transmittances among various digital cameras.…”
Section: Introductionmentioning
confidence: 99%
“…Most digital cameras use a Bayer pattern array of filters to obtain red, green and blue bands for a digital image [18,19]; however, the chemical basis for making these filters is proprietary and there is variation in filter spectral transmittances among various digital cameras. Typically, Bayer-pattern filters transmit at least some near-infrared (NIR) light through either the blue, green or red channels, so almost all commercially-available digital cameras have an internal hot-mirror filter blocking NIR light.…”
Section: Introductionmentioning
confidence: 99%
“…Typically, Bayer-pattern filters transmit at least some near-infrared (NIR) light through either the blue, green or red channels, so almost all commercially-available digital cameras have an internal hot-mirror filter blocking NIR light. This filter can be removed allowing detection of reflected NIR radiation from vegetation [18,19].…”
Payload size and weight are critical factors for small Unmanned Aerial Vehicles (UAVs). Digital color-infrared photographs were acquired from a single 12-megapixel camera that did not have an internal hot-mirror filter and had a red-light-blocking filter in front of the lens, resulting in near-infrared (NIR), green and blue images. We tested the UAV-camera system over two variably-fertilized fields of winter wheat and found a good correlation between leaf area index and the green normalized difference vegetation index (GNDVI). The low cost and very-high spatial resolution associated with the camera-UAV system may provide important information for site-specific agriculture.
“…Digital photography uses either silicon-based charge-coupled detectors or complementary metal-oxide-semiconductors, both of which have a spectral sensitivity from about 350 nm to about 1,100 nm wavelength [18,19]. Most digital cameras use a Bayer pattern array of filters to obtain red, green and blue bands for a digital image [18,19]; however, the chemical basis for making these filters is proprietary and there is variation in filter spectral transmittances among various digital cameras.…”
Section: Introductionmentioning
confidence: 99%
“…Most digital cameras use a Bayer pattern array of filters to obtain red, green and blue bands for a digital image [18,19]; however, the chemical basis for making these filters is proprietary and there is variation in filter spectral transmittances among various digital cameras. Typically, Bayer-pattern filters transmit at least some near-infrared (NIR) light through either the blue, green or red channels, so almost all commercially-available digital cameras have an internal hot-mirror filter blocking NIR light.…”
Section: Introductionmentioning
confidence: 99%
“…Typically, Bayer-pattern filters transmit at least some near-infrared (NIR) light through either the blue, green or red channels, so almost all commercially-available digital cameras have an internal hot-mirror filter blocking NIR light. This filter can be removed allowing detection of reflected NIR radiation from vegetation [18,19].…”
Payload size and weight are critical factors for small Unmanned Aerial Vehicles (UAVs). Digital color-infrared photographs were acquired from a single 12-megapixel camera that did not have an internal hot-mirror filter and had a red-light-blocking filter in front of the lens, resulting in near-infrared (NIR), green and blue images. We tested the UAV-camera system over two variably-fertilized fields of winter wheat and found a good correlation between leaf area index and the green normalized difference vegetation index (GNDVI). The low cost and very-high spatial resolution associated with the camera-UAV system may provide important information for site-specific agriculture.
“…The only modification made to the off-the-shelf version was removal of the NIR blocking filter. This modification increases the camera's sensitivity to red light and hence allows a better use of the spectral sensitivity of the image sensor (Lebourgeois et al 2008). The Canon 1000D camera has an optical resolution of 10.1 million effective pixels (3888 ¥ 2592) and a sensor size of 22.2 ¥ 14.8 mm.…”
A simple, high resolution colormetric planar optode imaging approach is presented. The approach is simple and inexpensive yet versatile, and can be used to study the two-dimensional distribution and dynamics of a range of analytes. The imaging approach utilizes the inbuilt color filter of standard commercial digital single lens reflex cameras to simultaneously record different colors (red, green, and blue) of luminophore emission light using only one excitation light source. Using the ratio between the intensity of the different colors recorded in a single image analyte concentrations can be calculated. The robustness of the approach is documented by obtaining high resolution data of O 2 and pH distributions in marine sediments using easy synthesizable sensors. The sensors rely on the platinum(II)octaethylporphyrin (PtOEP) and lipophilic 8-Hydroxy-1,3,6-pyrenetrisulfonic acid trisodium (HPTS) salt derivate for O 2 and pH measurements, respectively. The brightness of both indicators is dramatically enhanced by making use of energy transfer from a donor molecule (Macrolex yellow coumarin). Furthermore, the emission from the donor serves as an internal reference for the O 2 sensor. The approach relies on semitransparent sensors, facilitating visual inspection of the sediment behind the sensors during measurements. Software for data acquisition and calibration will be available from the authors, whereas all hardware is available from a range of commercial sources. The total cost of the complete measuring system is approximately $3000 US.
“…Although pixel interpolation lowers the effective spatial resolution of the band images, there is no need to align the three band images. Consequently, consumer-grade digital color cameras have been increasingly used by researchers for agricultural applications [16][17][18][19].…”
This paper describes the design and evaluation of an airborne multispectral imaging system based on two identical consumer-grade cameras for agricultural remote sensing. The cameras are equipped with a full-frame complementary metal oxide semiconductor (CMOS) sensor with 5616 × 3744 pixels. One camera captures normal color images, while the other is modified to obtain near-infrared (NIR) images. The color camera is also equipped with a GPS receiver to allow geotagged images. A remote control is used to trigger both cameras simultaneously. Images are stored in 14-bit RAW and 8-bit JPEG files in CompactFlash cards. The second-order transformation was used to align the color and NIR images to achieve subpixel alignment in four-band images. The imaging system was tested under various flight and land cover conditions and optimal camera settings were determined for airborne image acquisition. Images were captured at altitudes of 305-3050 m (1000-10,000 ft) and pixel sizes of 0.1-1.0 m were achieved. Four practical application examples are presented to illustrate how the imaging system was used to estimate cotton canopy cover, detect cotton root rot, and map henbit and giant
OPEN ACCESSRemote Sens. 2014, 6 5258 reed infestations. Preliminary analysis of example images has shown that this system has potential for crop condition assessment, pest detection, and other agricultural applications.
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