KERRY B WALSH | CQ University Australia (original) (raw)

Papers by KERRY B WALSH

Molecules

Infrared spectroscopy (wavelengths ranging from 750–25,000 nm) offers a rapid means of assessing ... more Infrared spectroscopy (wavelengths ranging from 750–25,000 nm) offers a rapid means of assessing the chemical composition of a wide range of sample types, both for qualitative and quantitative analyses. Its use in the food industry has increased significantly over the past five decades and it is now an accepted analytical technique for the routine analysis of certain analytes. Furthermore, it is commonly used for routine screening and quality control purposes in numerous industry settings, albeit not typically for the analysis of bioactive compounds. Using the Scopus database, a systematic search of literature of the five years between 2016 and 2020 identified 45 studies using near-infrared and 17 studies using mid-infrared spectroscopy for the quantification of bioactive compounds in food products. The most common bioactive compounds assessed were polyphenols, anthocyanins, carotenoids and ascorbic acid. Numerous factors affect the accuracy of the developed model, including the ana...

Sustainability, Jan 17, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Clinical Complementary Medicine and Pharmacology, 2022

Journal of Ethnopharmacology, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Acta Horticulturae, 2016

Spectral indices can be used in assessment of pigment level of intact plant material, and thus th... more Spectral indices can be used in assessment of pigment level of intact plant material, and thus there exists the possibly of using spectral indices as a measure of fruit maturity and ripeness. Spectra of tomato, banana and mango fruit were collected with a Nirvana handheld unit (Integrated Spectronics, Australia). A number of spectral indices: greenness index = R554/R677; DA index = A670-A720; chlorophyll index = R800/R700-1; Car/Chl ratio = (R678-R500)/R750; chlorophyll ratio = (R750/R700) and xanthophyll index = (R530-R570)/(R530+R570) were assessed. Tomato maturity was best discriminated using the Tomato index and carotene/chlorophyll ratio, while mango maturation and banana ripening were best indexed by DA index and chlorophyll ratio.

Postharvest Biology and Technology, 2009

... Manufacturing Co. in 1986 (www.makiss.co.jp). In this technique, the fruit was impacted by a ... more ... Manufacturing Co. in 1986 (www.makiss.co.jp). In this technique, the fruit was impacted by a small hammer, and the resulting sound wave was detected using three microphones positioned around the equator of the fruit. The sound ...

Sensors, Jun 18, 2019

Pre-harvest fruit yield estimation is useful to guide harvesting and marketing resourcing, but ma... more Pre-harvest fruit yield estimation is useful to guide harvesting and marketing resourcing, but machine vision estimates based on a single view from each side of the tree ("dual-view") underestimates the fruit yield as fruit can be hidden from view. A method is proposed involving deep learning, Kalman filter, and Hungarian algorithm for on-tree mango fruit detection, tracking, and counting from 10 frame-per-second videos captured of trees from a platform moving along the inter row at 5 km/h. The deep learning based mango fruit detection algorithm, MangoYOLO, was used to detect fruit in each frame. The Hungarian algorithm was used to correlate fruit between neighbouring frames, with the improvement of enabling multiple-to-one assignment. The Kalman filter was used to predict the position of fruit in following frames, to avoid multiple counts of a single fruit that is obscured or otherwise not detected with a frame series. A "borrow" concept was added to the Kalman filter to predict fruit position when its precise prediction model was absent, by borrowing the horizontal and vertical speed from neighbouring fruit. By comparison with human count for a video with 110 frames and 192 (human count) fruit, the method produced 9.9% double counts and 7.3% missing count errors, resulting in around 2.6% over count. In another test, a video (of 1162 frames, with 42 images centred on the tree trunk) was acquired of both sides of a row of 21 trees, for which the harvest fruit count was 3286 (i.e., average of 156 fruit/tree). The trees had thick canopies, such that the proportion of fruit hidden from view from any given perspective was high. The proposed method recorded 2050 fruit (62% of harvest) with a bias corrected Root Mean Square Error (RMSE) = 18.0 fruit/tree while the dual-view image method (also using MangoYOLO) recorded 1322 fruit (40%) with a bias corrected RMSE = 21.7 fruit/tree. The video tracking system is recommended over the dual-view imaging system for mango orchard fruit count.

Journal of Near Infrared Spectroscopy, 2021

Fourier-transform near infrared spectroscopy (FT-NIR) has been used in assessment of sectioned or... more Fourier-transform near infrared spectroscopy (FT-NIR) has been used in assessment of sectioned or pulverised teeth, and some consideration has been given to intact teeth in context of demineralisation and decay. This study considered the use of FT-NIR for characterization of sound (undecayed) intact teeth, both inside and outside custody bags. Replicate spectra of the same unbagged tooth were consistently grouped in principal component (PC) space, while spectra from different teeth were separated in PC space. The window of the custody bag carried a spectral signature that impacted the tooth-in-bag spectra, but subtraction of the window spectrum from tooth-in-bag spectra was successful in removal of this influence, with the corrected tooth-in-bag spectra aligning to the spectra of the same tooth outside the bag in PC space. Spectra of teeth of the same individual were discriminated from those of other individuals. Potential applications of this technology are discussed.

Infrared Physics & Technology, 2021

Abstract Estimation of on-tree mango maturity is essential for the prediction of harvest time. Dr... more Abstract Estimation of on-tree mango maturity is essential for the prediction of harvest time. Dry matter (DM) is a useful index in deciding mango maturity, and post-harvest quality. Existing NIR based maturity meters employ machine learning regressors to predict a maturity index value (such as DM, oBrix, or etc.) and then impose a hard threshold on predicted value to estimate maturity state of the fruit. In this paper, a new approach for non-destructive hand-held fruit maturity meter is investigated. The developed approach directly classifies the maturity state (mature/immature) using a classifier trained on maturity labels assigned through standard DM thresholds for investigated mango varieties. To develop the hardware of the device, a commercial-off-the-shelf development kit of NIR micro-spectrometer in the spectral range of 400 - 1100 nm was used with an embedded computational hardware, a micro-halogen lamp, a lithium battery, and a display. The application software (developed in C++) is designed to collect interactance spectra, remove noise, reduce dimensionality, and classify maturity state. Performance of the developed approach is evaluated by on-tree test samples of mango fruit of different season. Comparison of both the literature reported indirect maturity estimation and proposed direct maturity classification is conducted. The test results show that the maximum accuracy achieved using indirect maturity estimation using hard thresholds is 55.9%. Whereas direct maturity classification using KNN achieved 88.2% accuracy in predicting the maturity state (mature/immature) of the test mangoes. Overall results show that the developed DM mango maturity method has considerable potential to detect maturity state of mangoes in practical situations.

Postharvest Biology and Technology, 2021

Short wave near infrared spectroscopy has found use in non-invasive assessment of dry matter cont... more Short wave near infrared spectroscopy has found use in non-invasive assessment of dry matter content (DMC, % fresh weight) of mango fruit, both as a guide to harvest maturity and ensure eating quality of ripened fruit. In this study, this application is optimised in terms of pre-processing of spectra, the source of variations important to model performance documented, and the performance of cultivar or physiological stage specific partial least squares regression (PLSR) models, global PLSR and an artificial neural network (ANN) model are compared. The data set consisted of 4675 samples acquired across four seasons, ten cultivars and two growing regions, with harvest populations used as cross validation groups. The data of the fourth season was reserved as an independent test set. Spectra pre-treatment of mean centred Savitzy-Golay second derivative (second order polynomial using a 17 point interval) and use of the wavelength range 684−990 nm gave the lowest RMSECV for PLSR models, although other ranges had similar statistics. The fruit physiological stage had the greatest impact on PLSR model performance, compared to cultivar, year or growing region, as estimated using a 'variable importance metric' devised and implemented using a random forest regression. The use of specific (cultivar or physiological stage) PLSR models improved prediction results of the independent validation set (RMSEP on DMC decreased from 1.01 to 0.88 %), and was similar to the result of a global ANN model (0.89 %). The use of an ANN model is recommended in terms of ease of use of a single model across all cultivars.

Acta Horticulturae, 2016

There is a trend to take instrumentation from the laboratory to the field, e.g., a range of spect... more There is a trend to take instrumentation from the laboratory to the field, e.g., a range of spectrophotometers are commercially available for in field assessment of fruit attributes. Unfortunately, field users tend to place less emphasis on instrument maintenance, so understanding performance issues is important. Deterioration of lamp output quality over time and degradation of detector signal to noise ratio are some of the issues associated with aging of an instrument. To document the effect of instrument aging on fruit quality prediction, an experiment was conducted with three handheld spectrophotometers, with repeated spectra of a reference Teflon tile, and spectra of 20 apple fruit acquired at yearly intervals. Fruit TSS was also assessed, and used in development of a PLS regression models. The repeatability of each instrument was assessed as the standard deviation of absorbance, typically around 0.1 mAbs. Instrument changes were identified in performance and in PCA plots, but performance (apple TSS model) was not related to instrument repeatability.

Agronomy

A web mapping XYZ Tile Layer Service, such as Google Earth (GE), provides an amazing resource for... more A web mapping XYZ Tile Layer Service, such as Google Earth (GE), provides an amazing resource for the visualization of spatial data against aerial and satellite imagery with global coverage, typically at a resolution finer than 5 m. However, the increasing requirement on spatial accuracy in farm information requires a greater appreciation of the issues involved in the use of such services. Position errors can be created in the georeferencing and orthorectification of images, transformation between reference frames (datums) in map projection, e.g., using a spheroid as compared to an ellipsoid earth model, and tectonic shifts. A review is provided of these issues, and a case study is provided of the horizontal positional accuracy of web map imagery for Australian mango orchards. Positional accuracies varied from 1.804 to 6.131 m across four farms using GE 2021 imagery, between 1.556 and 3.365 m in one farm for the most recent imagery available from each of four web map providers, and ...

Applied Spectroscopy, May 1, 2001

In near-infrared (NIR) spectroscopy, the transfer of predictive models between Fourier transform ... more In near-infrared (NIR) spectroscopy, the transfer of predictive models between Fourier transform near-infrared (FT-NIR) and scanning-grating-based instruments has been accomplished on relatively dry samples (,10% water) using various chemometric techniques-for example, slope and bias correction (SBC), direct standardization (DS), piecew ise direct standardization (PDS), orthogonal signal correction (OSC), nite impulse transform (FIR) and wavelet transform (W T), and application of neural networks. In this study, seven well-known techniques [SBC, DS, PDS, doublewindow PDS (DWPDS), OSC, FIR, and WT], a photometric response correction and wavelength interpolative method, and a model updating method were assessed in terms of root mean square error of prediction (RM SEP) (using Fearn's signi cance testing) for calibration transfer (standardization) between pairs of spectrometers from a group of four spectrom eters for noninvasive prediction of soluble solid content (SSC) of melon fruit. The spectrometers were diffraction grating-based instruments incorporating photodiode array photodetectors (M MS1, Carl Zeiss, Jena, Germ any), used with a standard optical geometry of sample, light source, and spectrometer. A modi ed W T method performed signi cantly better than all other standardization methods and on a par with model updating.

Acta horticulturae, Feb 1, 2023

Applied sciences, Apr 20, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Molecules

Infrared spectroscopy (wavelengths ranging from 750–25,000 nm) offers a rapid means of assessing ... more Infrared spectroscopy (wavelengths ranging from 750–25,000 nm) offers a rapid means of assessing the chemical composition of a wide range of sample types, both for qualitative and quantitative analyses. Its use in the food industry has increased significantly over the past five decades and it is now an accepted analytical technique for the routine analysis of certain analytes. Furthermore, it is commonly used for routine screening and quality control purposes in numerous industry settings, albeit not typically for the analysis of bioactive compounds. Using the Scopus database, a systematic search of literature of the five years between 2016 and 2020 identified 45 studies using near-infrared and 17 studies using mid-infrared spectroscopy for the quantification of bioactive compounds in food products. The most common bioactive compounds assessed were polyphenols, anthocyanins, carotenoids and ascorbic acid. Numerous factors affect the accuracy of the developed model, including the ana...

Sustainability, Jan 17, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

Clinical Complementary Medicine and Pharmacology, 2022

Journal of Ethnopharmacology, 2021

This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Acta Horticulturae, 2016

Spectral indices can be used in assessment of pigment level of intact plant material, and thus th... more Spectral indices can be used in assessment of pigment level of intact plant material, and thus there exists the possibly of using spectral indices as a measure of fruit maturity and ripeness. Spectra of tomato, banana and mango fruit were collected with a Nirvana handheld unit (Integrated Spectronics, Australia). A number of spectral indices: greenness index = R554/R677; DA index = A670-A720; chlorophyll index = R800/R700-1; Car/Chl ratio = (R678-R500)/R750; chlorophyll ratio = (R750/R700) and xanthophyll index = (R530-R570)/(R530+R570) were assessed. Tomato maturity was best discriminated using the Tomato index and carotene/chlorophyll ratio, while mango maturation and banana ripening were best indexed by DA index and chlorophyll ratio.

Postharvest Biology and Technology, 2009

... Manufacturing Co. in 1986 (www.makiss.co.jp). In this technique, the fruit was impacted by a ... more ... Manufacturing Co. in 1986 (www.makiss.co.jp). In this technique, the fruit was impacted by a small hammer, and the resulting sound wave was detected using three microphones positioned around the equator of the fruit. The sound ...

Sensors, Jun 18, 2019

Pre-harvest fruit yield estimation is useful to guide harvesting and marketing resourcing, but ma... more Pre-harvest fruit yield estimation is useful to guide harvesting and marketing resourcing, but machine vision estimates based on a single view from each side of the tree ("dual-view") underestimates the fruit yield as fruit can be hidden from view. A method is proposed involving deep learning, Kalman filter, and Hungarian algorithm for on-tree mango fruit detection, tracking, and counting from 10 frame-per-second videos captured of trees from a platform moving along the inter row at 5 km/h. The deep learning based mango fruit detection algorithm, MangoYOLO, was used to detect fruit in each frame. The Hungarian algorithm was used to correlate fruit between neighbouring frames, with the improvement of enabling multiple-to-one assignment. The Kalman filter was used to predict the position of fruit in following frames, to avoid multiple counts of a single fruit that is obscured or otherwise not detected with a frame series. A "borrow" concept was added to the Kalman filter to predict fruit position when its precise prediction model was absent, by borrowing the horizontal and vertical speed from neighbouring fruit. By comparison with human count for a video with 110 frames and 192 (human count) fruit, the method produced 9.9% double counts and 7.3% missing count errors, resulting in around 2.6% over count. In another test, a video (of 1162 frames, with 42 images centred on the tree trunk) was acquired of both sides of a row of 21 trees, for which the harvest fruit count was 3286 (i.e., average of 156 fruit/tree). The trees had thick canopies, such that the proportion of fruit hidden from view from any given perspective was high. The proposed method recorded 2050 fruit (62% of harvest) with a bias corrected Root Mean Square Error (RMSE) = 18.0 fruit/tree while the dual-view image method (also using MangoYOLO) recorded 1322 fruit (40%) with a bias corrected RMSE = 21.7 fruit/tree. The video tracking system is recommended over the dual-view imaging system for mango orchard fruit count.

Journal of Near Infrared Spectroscopy, 2021

Fourier-transform near infrared spectroscopy (FT-NIR) has been used in assessment of sectioned or... more Fourier-transform near infrared spectroscopy (FT-NIR) has been used in assessment of sectioned or pulverised teeth, and some consideration has been given to intact teeth in context of demineralisation and decay. This study considered the use of FT-NIR for characterization of sound (undecayed) intact teeth, both inside and outside custody bags. Replicate spectra of the same unbagged tooth were consistently grouped in principal component (PC) space, while spectra from different teeth were separated in PC space. The window of the custody bag carried a spectral signature that impacted the tooth-in-bag spectra, but subtraction of the window spectrum from tooth-in-bag spectra was successful in removal of this influence, with the corrected tooth-in-bag spectra aligning to the spectra of the same tooth outside the bag in PC space. Spectra of teeth of the same individual were discriminated from those of other individuals. Potential applications of this technology are discussed.

Infrared Physics & Technology, 2021

Abstract Estimation of on-tree mango maturity is essential for the prediction of harvest time. Dr... more Abstract Estimation of on-tree mango maturity is essential for the prediction of harvest time. Dry matter (DM) is a useful index in deciding mango maturity, and post-harvest quality. Existing NIR based maturity meters employ machine learning regressors to predict a maturity index value (such as DM, oBrix, or etc.) and then impose a hard threshold on predicted value to estimate maturity state of the fruit. In this paper, a new approach for non-destructive hand-held fruit maturity meter is investigated. The developed approach directly classifies the maturity state (mature/immature) using a classifier trained on maturity labels assigned through standard DM thresholds for investigated mango varieties. To develop the hardware of the device, a commercial-off-the-shelf development kit of NIR micro-spectrometer in the spectral range of 400 - 1100 nm was used with an embedded computational hardware, a micro-halogen lamp, a lithium battery, and a display. The application software (developed in C++) is designed to collect interactance spectra, remove noise, reduce dimensionality, and classify maturity state. Performance of the developed approach is evaluated by on-tree test samples of mango fruit of different season. Comparison of both the literature reported indirect maturity estimation and proposed direct maturity classification is conducted. The test results show that the maximum accuracy achieved using indirect maturity estimation using hard thresholds is 55.9%. Whereas direct maturity classification using KNN achieved 88.2% accuracy in predicting the maturity state (mature/immature) of the test mangoes. Overall results show that the developed DM mango maturity method has considerable potential to detect maturity state of mangoes in practical situations.

Postharvest Biology and Technology, 2021

Short wave near infrared spectroscopy has found use in non-invasive assessment of dry matter cont... more Short wave near infrared spectroscopy has found use in non-invasive assessment of dry matter content (DMC, % fresh weight) of mango fruit, both as a guide to harvest maturity and ensure eating quality of ripened fruit. In this study, this application is optimised in terms of pre-processing of spectra, the source of variations important to model performance documented, and the performance of cultivar or physiological stage specific partial least squares regression (PLSR) models, global PLSR and an artificial neural network (ANN) model are compared. The data set consisted of 4675 samples acquired across four seasons, ten cultivars and two growing regions, with harvest populations used as cross validation groups. The data of the fourth season was reserved as an independent test set. Spectra pre-treatment of mean centred Savitzy-Golay second derivative (second order polynomial using a 17 point interval) and use of the wavelength range 684−990 nm gave the lowest RMSECV for PLSR models, although other ranges had similar statistics. The fruit physiological stage had the greatest impact on PLSR model performance, compared to cultivar, year or growing region, as estimated using a 'variable importance metric' devised and implemented using a random forest regression. The use of specific (cultivar or physiological stage) PLSR models improved prediction results of the independent validation set (RMSEP on DMC decreased from 1.01 to 0.88 %), and was similar to the result of a global ANN model (0.89 %). The use of an ANN model is recommended in terms of ease of use of a single model across all cultivars.

Acta Horticulturae, 2016

There is a trend to take instrumentation from the laboratory to the field, e.g., a range of spect... more There is a trend to take instrumentation from the laboratory to the field, e.g., a range of spectrophotometers are commercially available for in field assessment of fruit attributes. Unfortunately, field users tend to place less emphasis on instrument maintenance, so understanding performance issues is important. Deterioration of lamp output quality over time and degradation of detector signal to noise ratio are some of the issues associated with aging of an instrument. To document the effect of instrument aging on fruit quality prediction, an experiment was conducted with three handheld spectrophotometers, with repeated spectra of a reference Teflon tile, and spectra of 20 apple fruit acquired at yearly intervals. Fruit TSS was also assessed, and used in development of a PLS regression models. The repeatability of each instrument was assessed as the standard deviation of absorbance, typically around 0.1 mAbs. Instrument changes were identified in performance and in PCA plots, but performance (apple TSS model) was not related to instrument repeatability.

Agronomy

A web mapping XYZ Tile Layer Service, such as Google Earth (GE), provides an amazing resource for... more A web mapping XYZ Tile Layer Service, such as Google Earth (GE), provides an amazing resource for the visualization of spatial data against aerial and satellite imagery with global coverage, typically at a resolution finer than 5 m. However, the increasing requirement on spatial accuracy in farm information requires a greater appreciation of the issues involved in the use of such services. Position errors can be created in the georeferencing and orthorectification of images, transformation between reference frames (datums) in map projection, e.g., using a spheroid as compared to an ellipsoid earth model, and tectonic shifts. A review is provided of these issues, and a case study is provided of the horizontal positional accuracy of web map imagery for Australian mango orchards. Positional accuracies varied from 1.804 to 6.131 m across four farms using GE 2021 imagery, between 1.556 and 3.365 m in one farm for the most recent imagery available from each of four web map providers, and ...

Applied Spectroscopy, May 1, 2001

In near-infrared (NIR) spectroscopy, the transfer of predictive models between Fourier transform ... more In near-infrared (NIR) spectroscopy, the transfer of predictive models between Fourier transform near-infrared (FT-NIR) and scanning-grating-based instruments has been accomplished on relatively dry samples (,10% water) using various chemometric techniques-for example, slope and bias correction (SBC), direct standardization (DS), piecew ise direct standardization (PDS), orthogonal signal correction (OSC), nite impulse transform (FIR) and wavelet transform (W T), and application of neural networks. In this study, seven well-known techniques [SBC, DS, PDS, doublewindow PDS (DWPDS), OSC, FIR, and WT], a photometric response correction and wavelength interpolative method, and a model updating method were assessed in terms of root mean square error of prediction (RM SEP) (using Fearn's signi cance testing) for calibration transfer (standardization) between pairs of spectrometers from a group of four spectrom eters for noninvasive prediction of soluble solid content (SSC) of melon fruit. The spectrometers were diffraction grating-based instruments incorporating photodiode array photodetectors (M MS1, Carl Zeiss, Jena, Germ any), used with a standard optical geometry of sample, light source, and spectrometer. A modi ed W T method performed signi cantly better than all other standardization methods and on a par with model updating.

Acta horticulturae, Feb 1, 2023

Applied sciences, Apr 20, 2023

This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY