No description available.

No description available.

No description available.

No description available.

In this work the development and construction of a new near-infrared imaging spectrometer utilising inexpensive components is presented. The instrument is applied to measuring the distribution of constituents in fruit, in particular, soluble solids and dry matter in kiwifruit. The spectrometer, designed for collecting spectral-images of fruit, uses a diffraction grating for spectral dispersion, a scanning slit system for spatial resolution and a CCD detector to allow images of samples to be examined in different wavebands. The system described has a spectral range of 650 nm to 1100 nm at a resolution of better than 5 nm. Each spectral-image contains 150 x 242 pixels on the spatial plane and 755 pixels for the spectral ads. An interchangeable imaging lens enables investigation of samples at different scales. With a 58 mm camera lens objects up to 50 mm x 50 mm may be imaged at a spatial resolution of up to 2 line-pairs per millimetre (0.5 millimetre). One difficulty with calibration using spectral-images is that the independent measurements of concentration often come from areas much larger than a pixel. For spectral-imaging to be useful it is important that the calibration can estimate concentration at the pixel level. In effect this means estimates calculated using the model are more accurate than the independent measurements used in calibration. Using synthetic spectra and an investigation of the principal component regression algorithm, the ability of a calibration, from spectral-images, to estimate these pixel level concentrations has been demonstrated. To calibrate the instrument for measuring soluble solids concentration and dry matter content in kiwifruit, reflectance spectra from 650 nm to 1100 nm were collected from cut sections of 200 fruit. A near-infrared calibration was obtained by recording the soluble solids concentration and dry matter content of plugs extracted from thin slices of the fruit and relating these to the spectra collected. A prediction error of 1.2 °Brix over a range of 4.7 - 14.1 °Brix was achieved. It was not possible to obtain a useful model for estimating dry matter due to interference from specular reflections off free juice in the fruit. The models developed were used to show the spatial distribution of soluble solid concentrations over cut sections of fruit.

In this work the development and construction of a new near-infrared imaging spectrometer utilising inexpensive components is presented. The instrument is applied to measuring the distribution of constituents in fruit, in particular, soluble solids and dry matter in kiwifruit. The spectrometer, designed for collecting spectral-images of fruit, uses a diffraction grating for spectral dispersion, a scanning slit system for spatial resolution and a CCD detector to allow images of samples to be examined in different wavebands. The system described has a spectral range of 650 nm to 1100 nm at a resolution of better than 5 nm. Each spectral-image contains 150 x 242 pixels on the spatial plane and 755 pixels for the spectral ads. An interchangeable imaging lens enables investigation of samples at different scales. With a 58 mm camera lens objects up to 50 mm x 50 mm may be imaged at a spatial resolution of up to 2 line-pairs per millimetre (0.5 millimetre). One difficulty with calibration using spectral-images is that the independent measurements of concentration often come from areas much larger than a pixel. For spectral-imaging to be useful it is important that the calibration can estimate concentration at the pixel level. In effect this means estimates calculated using the model are more accurate than the independent measurements used in calibration. Using synthetic spectra and an investigation of the principal component regression algorithm, the ability of a calibration, from spectral-images, to estimate these pixel level concentrations has been demonstrated. To calibrate the instrument for measuring soluble solids concentration and dry matter content in kiwifruit, reflectance spectra from 650 nm to 1100 nm were collected from cut sections of 200 fruit. A near-infrared calibration was obtained by recording the soluble solids concentration and dry matter content of plugs extracted from thin slices of the fruit and relating these to the spectra collected. A prediction error of 1.2 °Brix over a range of 4.7 - 14.1 °Brix was achieved. It was not possible to obtain a useful model for estimating dry matter due to interference from specular reflections off free juice in the fruit. The models developed were used to show the spatial distribution of soluble solid concentrations over cut sections of fruit.

In this work the development and construction of a new near-infrared imaging spectrometer utilising inexpensive components is presented. The instrument is applied to measuring the distribution of constituents in fruit, in particular, soluble solids and dry matter in kiwifruit. The spectrometer, designed for collecting spectral-images of fruit, uses a diffraction grating for spectral dispersion, a scanning slit system for spatial resolution and a CCD detector to allow images of samples to be examined in different wavebands. The system described has a spectral range of 650 nm to 1100 nm at a resolution of better than 5 nm. Each spectral-image contains 150 x 242 pixels on the spatial plane and 755 pixels for the spectral ads. An interchangeable imaging lens enables investigation of samples at different scales. With a 58 mm camera lens objects up to 50 mm x 50 mm may be imaged at a spatial resolution of up to 2 line-pairs per millimetre (0.5 millimetre). One difficulty with calibration using spectral-images is that the independent measurements of concentration often come from areas much larger than a pixel. For spectral-imaging to be useful it is important that the calibration can estimate concentration at the pixel level. In effect this means estimates calculated using the model are more accurate than the independent measurements used in calibration. Using synthetic spectra and an investigation of the principal component regression algorithm, the ability of a calibration, from spectral-images, to estimate these pixel level concentrations has been demonstrated. To calibrate the instrument for measuring soluble solids concentration and dry matter content in kiwifruit, reflectance spectra from 650 nm to 1100 nm were collected from cut sections of 200 fruit. A near-infrared calibration was obtained by recording the soluble solids concentration and dry matter content of plugs extracted from thin slices of the fruit and relating these to the spectra collected. A prediction error of 1.2 °Brix over a range of 4.7 - 14.1 °Brix was achieved. It was not possible to obtain a useful model for estimating dry matter due to interference from specular reflections off free juice in the fruit. The models developed were used to show the spatial distribution of soluble solid concentrations over cut sections of fruit.

In this work the development and construction of a new near-infrared imaging spectrometer utilising inexpensive components is presented. The instrument is applied to measuring the distribution of constituents in fruit, in particular, soluble solids and dry matter in kiwifruit. The spectrometer, designed for collecting spectral-images of fruit, uses a diffraction grating for spectral dispersion, a scanning slit system for spatial resolution and a CCD detector to allow images of samples to be examined in different wavebands. The system described has a spectral range of 650 nm to 1100 nm at a resolution of better than 5 nm. Each spectral-image contains 150 x 242 pixels on the spatial plane and 755 pixels for the spectral ads. An interchangeable imaging lens enables investigation of samples at different scales. With a 58 mm camera lens objects up to 50 mm x 50 mm may be imaged at a spatial resolution of up to 2 line-pairs per millimetre (0.5 millimetre). One difficulty with calibration using spectral-images is that the independent measurements of concentration often come from areas much larger than a pixel. For spectral-imaging to be useful it is important that the calibration can estimate concentration at the pixel level. In effect this means estimates calculated using the model are more accurate than the independent measurements used in calibration. Using synthetic spectra and an investigation of the principal component regression algorithm, the ability of a calibration, from spectral-images, to estimate these pixel level concentrations has been demonstrated. To calibrate the instrument for measuring soluble solids concentration and dry matter content in kiwifruit, reflectance spectra from 650 nm to 1100 nm were collected from cut sections of 200 fruit. A near-infrared calibration was obtained by recording the soluble solids concentration and dry matter content of plugs extracted from thin slices of the fruit and relating these to the spectra collected. A prediction error of 1.2 °Brix over a range of 4.7 - 14.1 °Brix was achieved. It was not possible to obtain a useful model for estimating dry matter due to interference from specular reflections off free juice in the fruit. The models developed were used to show the spatial distribution of soluble solid concentrations over cut sections of fruit.

Major agronomic and economic losses are caused by inaccurate application of nutrients from ground based spreading vehicles. These losses come from both over and under application of fertiliser resulting from such practices as driving at inappropriate bout widths. This work reviewed current spreader testing procedures; compared the performance of international test methodologies and evaluated the use of a digital image processing program to perform spreader testing. Methods to evaluate field performance were developed; this analysis of field application was used to calculate the economic effect of using precision agricultural technologies in New Zealand dairy farming systems. A matrix of fourteen hundred 0.5 x 0.5 m fertiliser collection trays was used to evaluate individual test methodologies. Results indicated that there were major variations in calculated certifiable bout width between different methods and direct comparison should be avoided. Tray layout within ± 5 m of the centre spread line had the largest effect on calculated bout width whilst methods that incorporated rows of trays in the longitudinal direction were less variable compared to those using a single transverse test. The probability too accurately assign bout widths using different international test methods was analysed, the ACCU Spread (Australia) test method had the highest level of confidence in its bout width calculation followed by the ES (Europe) test method. The ISO(i) (World), ISO(ii) (World) and Spreadmark (NZ) tests were all found to be comparable to one another whilst the ASAE (USA) method had the lowest level of confidence in its bout width calculation because of wide collector tray spacing. A method to extract a wider range of data from spreader tests using a hybrid image processing system was developed. Results indicated that there was a strong relationship between two dimensional particle area and particle mass under laboratory (R2 = 0.991) and field (R2 = 0.988) conditions. Although transverse spreader tests provided a good indication of machine performance, they did not account for the interaction of the spreader and its operational environment. A method was developed that used the vehicle location during field application and the transverse spread pattern represented as polygons to create field application maps. Initial results showed large variations compared to the measured transverse spread pattern. A wider study over 102 paddocks on four dairy farms showed that average variation was 37.9%. An improvement to the field application method discussed is given; this tool used the geographical position, heading angle and a series of static spread pattern tests from the spreading vehicle to achieve greater accuracy in field measurements. The described field application methods were used to assess the ability to execute a nutrient plan using both actual and optimised spreading data collected during field application. A loss of $66.18 ha-1 was calculated when comparing the efficiency of using current spreading methods to those assumed in nutrient budgeting practice. If a guidance and control system were used correctly to provide optimised field application the loss could be reduced to $46.41 ha-1. This work highlighted the difficulties in achieving accurate field nutrient application; however, by developing the ability to quantify field performance, economic opportunities could be evaluated. Overall, this work found that there was a strong agronomic and economic case for the implementation of precision agricultural technologies in the New Zealand fertiliser industry. However, the current range of equipment used by the spreading industry would have difficulty in delivering these benefits.

Greater use of technology to assist aerial application of fertiliser will be of benefit to the topdressing industry and farmers. Benefits arise through automating the fertiliser flow control system; reducing off target fertiliser application, and managing fertiliser inputs based on the potential outputs of the farmland; thus increasing the profitability of hill country farming systems. A case for technology assisted application is developed by investigating the field performance of conventional and enhanced flow control systems and the effect of variable rate application on hill country pasture production. A single particle model that predicts flight trajectory from the particle force balance based on the aircraft groundspeed, axial and tangential propeller wash, wind characteristics and particle properties including sphericity was developed. Model predictions were compared to predictions from AGDISP 8.15. Results and trends were similar. The single particle ballistics model described above was extended to predict the lateral distribution of fertiliser after release from an aircraft. To achieve this, two parameters are important, the transverse flow profile of material leaving the hopper gatebox and the sphericity of the particles. Techniques for measuring these parameters are described and experimental results are presented for superphosphate. These data were used in the model to predict the lateral distribution pattern from a Gippsland Aeronautics 200C for a known discharge mass, which was compared to a measured pattern from the same aircraft for the same discharge mass. Good agreement between the shapes of the two distributions was found. The transverse distribution model provides a practical tool for optimising the design of spreaders, or optimum particle characteristics for a given spreader. It has the ability to predict the distribution profile of any particle size distribution from each, or all, of the spreader ducts. Culmination of the single particle and transverse distribution models led to the development of a deposition footprint model that was capable of predicting field application within a 25 ha trial site. The deposition footprint model was embedded inside a geographical information system and comparisons were made between the actual and predicted deposition across a series of transect lines. Good agreement was found. Following this, a comparison of the predicted field performance between an automated and manual control system were made. Economic benefits for a single application of superphosphate were identified through using automated control, where 10% less fertiliser was applied outside of the application zone when compared to the manually operated system. This equated to a net benefit of NZD $2800 for a 1500 ha hill country farming system. The value of improving the performance of a topdressing aircraft, on an industry level, was also examined. Cost/benefit analysis between a manual and automated system revealed a benefit of NZD $111,700 yr-1 for a single topdressing aircraft using the automated system. The economic impact of Variable Rate Application Technology (VRAT) is examined, using Limestone Downs as an example. The spatially explicit decision tree modelling technique was used to predict the annual pasture production over the entire Limestone Downs property. The resulting decision tree classes tended to follow the farm's digital elevation model. A series of six different fertiliser application scenarios were developed for comparison to a base line scenario using conventional aerial application techniques. VRAT outperformed the fixed rate applications in terms of pasture production and fertiliser utilisation. Full variable rate application and a model optimised prescription map, produced the highest annual pasture yield. Variable rate techniques were predicted to increase annual production and the spatial variability of that production. An economic analysis of the six production scenarios was undertaken. Farm cash surplus was calculated for each scenario and clearly revealed the benefits of using variable rate application technology. VRAT was found to be the most efficient and highest returning application method per hectare. Additional costs and increased charge-out rates were likely to occur under VRAT; nevertheless, the analysis indicated that significant financial incentives were available to the farmer. A sensitivity analysis revealed that even with a 20% increase in charge-out rate associated with VRAT, the farm's annual cash position varied by only $4500 (0.4%), suggesting the cost of implementing such a system is not prohibitive and would allow aircraft operators to add value to their services.