title: Investigation of in vitro diabetic inflammation and  treatment with Piper excelsum tea extract

authors: Harvey, Savannah

subjects: Piper excelsum

abstract: Induction of inflammation through hyperglycaemia and adiposity has been shown to contribute to the pathogenicity of type 2 diabetes (T2D). The pro-inflammatory cytokine, tumour necrosis factor α (TNF-α) was the first cytokine found to bridge the connection between the immune system and T2D. This was found due to its increased production in the disease state. TNF-α has specifically been linked to the onset of insulin resistance in T2D models. Evidence has shown that heat shock protein 60 (HSP60) may also play a role as a danger signal for the immune system as it can result in the induction of inflammation. Currently, there are no pharmaceutical options for T2D patients which target inflammation. Tea made from the leaves of kawakawa (Piper excelsum) has been used for many generations by Māori as a traditional rākau rongoā (traditional medicine) to treat a range of ailments including inflammation. The aim of this project was to investigate the modulation of inflammation using a commercially available kawakawa tea in human cancer cells in vitro. 

This project involved measuring the growth rate, cytotoxicity, TNF-α production and HSP60 expression upon exposure to three treatments: high glucose, lipopolysaccharide (LPS) or kawakawa tea extract (KTE).

This study showed that a high concentration of KTE (1000 µg/mL) inhibited cell growth in both HEPG2 and HeLa cell lines. Cells treated with this concentration also showed typical morphological signs of apoptosis. Cytotoxicity testing confirmed that there was a significant (p <0.05) decrease in mitochondrial dehydrogenase activity for this treatment which confirmed the cells were likely dying through apoptosis. Over a course of 24-hours three LPS treatments were found to be cytotoxic. These were the 10 ng/mL, 10 µg/mL, and 100 µg/mL concentrations of LPS. After 48-hours all treatments apart from 100 µg/mL KTE treatment were also found to be cytotoxic. The cytotoxicity for these treatments was either due to a reduction in mitochondrial dehydrogenase activity (infers mitochondrial stress) or increased lactate dehydrogenase (LDH) release from cells (infers necrotic cell death). These cytotoxicity experiments allowed for identification of which concentrations should be selected or removed for future experiments. 

Cytotoxicity levels were taken into consideration and experiments were run investigating the induction of TNF-α using enzyme-linked immunosorbent assays (ELISA). Issues regarding negative readings from samples arose which resulted in protocol changes and extensive trouble shooting. It was found that extended exposure times were required to attenuate a positive result from the positive control, LPS. 

HSP60 expression was also measured for human cells exposed to high glucose and KTE treatments. No change in HSP60 expression was detected. However, 24-hour LPS exposure resulted in a significant increase in HSP60 expression compared to the control for the 100 ng/mL LPS treatment. Two concentrations were investigated; 100 ng/mL LPS and 100 µg/mL LPS which resulted in 1.4- and 2.1-fold increases compared to the control, respectively.

Overall, no conclusion could be drawn regarding the modulation of inflammation by KTE. However, this study was able to identify the effect the tea has on human cancer cell growth and the nature of cytotoxicity the tea poses to the cells. It is recommended to continue this research exploring different kawakawa tea blends and using alternative in vitro cell lines and whole animal models.

text: Investigation of in vitro diabetic inflammation and  treatment with Piper excelsum tea extract Induction of inflammation through hyperglycaemia and adiposity has been shown to contribute to the pathogenicity of type 2 diabetes (T2D). The pro-inflammatory cytokine, tumour necrosis factor α (TNF-α) was the first cytokine found to bridge the connection between the immune system and T2D. This was found due to its increased production in the disease state. TNF-α has specifically been linked to the onset of insulin resistance in T2D models. Evidence has shown that heat shock protein 60 (HSP60) may also play a role as a danger signal for the immune system as it can result in the induction of inflammation. Currently, there are no pharmaceutical options for T2D patients which target inflammation. Tea made from the leaves of kawakawa (Piper excelsum) has been used for many generations by Māori as a traditional rākau rongoā (traditional medicine) to treat a range of ailments including inflammation. The aim of this project was to investigate the modulation of inflammation using a commercially available kawakawa tea in human cancer cells in vitro. 

This project involved measuring the growth rate, cytotoxicity, TNF-α production and HSP60 expression upon exposure to three treatments: high glucose, lipopolysaccharide (LPS) or kawakawa tea extract (KTE).

This study showed that a high concentration of KTE (1000 µg/mL) inhibited cell growth in both HEPG2 and HeLa cell lines. Cells treated with this concentration also showed typical morphological signs of apoptosis. Cytotoxicity testing confirmed that there was a significant (p <0.05) decrease in mitochondrial dehydrogenase activity for this treatment which confirmed the cells were likely dying through apoptosis. Over a course of 24-hours three LPS treatments were found to be cytotoxic. These were the 10 ng/mL, 10 µg/mL, and 100 µg/mL concentrations of LPS. After 48-hours all treatments apart from 100 µg/mL KTE treatment were also found to be cytotoxic. The cytotoxicity for these treatments was either due to a reduction in mitochondrial dehydrogenase activity (infers mitochondrial stress) or increased lactate dehydrogenase (LDH) release from cells (infers necrotic cell death). These cytotoxicity experiments allowed for identification of which concentrations should be selected or removed for future experiments. 

Cytotoxicity levels were taken into consideration and experiments were run investigating the induction of TNF-α using enzyme-linked immunosorbent assays (ELISA). Issues regarding negative readings from samples arose which resulted in protocol changes and extensive trouble shooting. It was found that extended exposure times were required to attenuate a positive result from the positive control, LPS. 

HSP60 expression was also measured for human cells exposed to high glucose and KTE treatments. No change in HSP60 expression was detected. However, 24-hour LPS exposure resulted in a significant increase in HSP60 expression compared to the control for the 100 ng/mL LPS treatment. Two concentrations were investigated; 100 ng/mL LPS and 100 µg/mL LPS which resulted in 1.4- and 2.1-fold increases compared to the control, respectively.

Overall, no conclusion could be drawn regarding the modulation of inflammation by KTE. However, this study was able to identify the effect the tea has on human cancer cell growth and the nature of cytotoxicity the tea poses to the cells. It is recommended to continue this research exploring different kawakawa tea blends and using alternative in vitro cell lines and whole animal models.

year: 2021

title: Reclaiming the Māori language for future generations: Flax root perspectives. Tīkina te mana o te reo Māori: Te pūtaketanga o te pā harakeke

authors: Peters, Murray Hamaka

subjects: te reo Māori

abstract: Using a combination of semi-structured interviews, focus group discussion and questionnaires (designed to elicit as many comments as possible), this thesis explores, through their own voices, the attitudes and practices of a group of people, mainly Māori but including a few Pākehā (non-Māori) who are attempting to reclaim te reo Māori (the Māori language), for themselves, their families and, above all, their children and grandchildren. Many of them were brought up in a context in which one or more parents, caregivers or relatives spoke te reo Māori fluently but few were given the opportunity to acquire the language naturally in infancy, generally because of a desire to protect them from the discrimination suffered by their elders. Those who were brought up to speak te reo Māori often suffered from language attrition at a time when the English language began to feature prominently in their lives. A few have attended kōhanga reo and kura kaupapa Māori. Many have attended courses in the Māori language and culture, often at considerable personal cost. Some have achieved their dream of becoming fluent speakers of the language; some have suffered frustration and disappointment. Whatever their own experiences, almost all of them want their children and grandchildren to be fluent speakers of the language, believing that this will give them confidence and a genuine sense of identity and belonging. Although the majority are committed to using te reo Māori as much as possible at home, especially when speaking to their children and grandchildren, most experience difficulties in doing so. These difficulties relate, in general, to their own lack of confidence and/or limited competence in the language, the fact that some of their friends and/or members of their immediate or extended family are monolingual in English, and resistance from some of the children, particularly as they grow older and are increasingly influenced by the dominant language and culture. Among those involved in this research project, there was widespread awareness of the importance of inter-generational transmission of te reo Māori and evidence of considerable commitment to learning the language and/or improving their existing competence in it. However, although the attempts of these adults to use te reo Māori in the home are clearly of considerable importance, they often, where they lacked a high level of oral proficiency, met with confusion, frustration, tension and resistance as their children grew older. This, combined with the fact that there are currently so few domains in society at large in which the language can be used naturally, has led many of them to develop strategies aimed at ensuring that their children and grandchildren, as they grow towards adulthood (a) appreciate the sacrifices made by so many in order to give them the opportunity to learn the language and the responsibilities associated with these sacrifices, (b) are recognised and rewarded for their linguistic achievements, and (c) are encouraged and assisted to involve themselves in contexts where they can use the language. This includes encouraging them to become involved in kapa haka and other culturally significant activities in which the language plays a prominent part, promoting as much engagement as possible with friends and whānau who have a high level of proficiency in the language (including involving them and their friends in marae-based activities), and inviting into their homes people who are fluent speakers (which sometimes involves a conscious effort on the part of the adults to cement friendships with fluent speakers and to encourage them to interact with their children). These are things which all parents and caregivers can do, irrespective of their own language competence. 

In doing these things, those who currently feel that they have little to offer in relation to the revitalization of the language can experience a genuine sense of involvement and empowerment. Accepting that there are currently many parents and caregivers who cannot realistically become involved in genuine inter-generational transmission of the language in the home does not mean accepting that they have nothing to offer. 

Mā te kōwhiringa o ngā uiuitanga hangā ngāwari, te whiriwhiri ā rōpū kanohi, me te puka patapātai (hei tōngia mai ngā kōrero whānui kē atu o tēnā, o tēnā), ka whakatewhatewha te tuhinga nei i ngā waiaro me ngā ritenga o tētehi rōpū e ngana ana ki te haumanu i te reo Māori hei taonga mō rātou ko ō rātou whānau, ā, mō ā rātou tamariki, mokopuna hoki. Te nuinga o te hunga nei he Māori; he tokoiti anō he Pākehā. He tokomaha o rātou i tipu ake i roto i te horopaki o te reo Māori, arā, kotahi neke atu o ō rātou mātua rānei, kaitiaki rānei, whanaunga rānei he matatau ki te reo Māori. Ahakoa rā, kāore te nuinga i whāngaihia ki te reo i ā rātou e pēpi ana, kei whakapai kanohitia pērā i ō rātou tūpuna. Ko rātou te hunga i tipu reo Māori mai, ka memeha haere tō rātou reo nō te tino putanga ake o te reo Pākehā ki ō rātou ao. He tokoiti o tēnei rōpu i kuraina ki te kōhanga reo me te kura kaupapa Māori; he tokomaha anō i whai wāhi ki ngā akoranga reo Māori me ōna tikanga, hāunga rā te nui o te nama. Ko ētehi, kua ea ngā wawata, kua matatau ki te reo; ko ētehi atu anō, kua pāngia kētia e te hōhā me te hēmanawatanga. Heoi, ahakoa ngā wheako ake o tēnā, o tēnā, he hiahia nō te nuinga kia matatau ā rātou tamariki me ā rātou mokopuna ki te reo, kia tū pakari ai, kia tū Māori ai ki tēnei ao. Te nuinga o tēnei rōpū he manawanui ki te kōrero Māori i te kāinga i te nuinga o te wā, koia anō rā i ā rātou e kōrero ana ki ā rātou tamariki me ā rātou mokopuna. Heoi anō, kei reira anō ngā papatoieketanga, e pā ana ki ō rātou ake tītengi rānei, ki te takarepatanga o tō rātou reo rānei, me te mōhio anō ko ētahi o ō rātou hoa, whānau, whānau whānui anō hoki, he reo tahi kē, arā, ko te reo Pākehā te reo kawe. Anō hoki, ko ētahi o ngā tamariki, i ā rātou e pakeke haere ana ka kaha papare i te reo Māori, ka whakawaia kētia rātou e te reo Pākehā me ōna tikanga. I waenganui i te hunga i whai wāhi ki tēnei kaupapa rangahau kua kitea he mārama pū te nuinga ki te tino hiranga o te tuku ihotanga o te reo; kua kitea hoki tō rātou kaingākau nui ki te ako i te reo, ki te whakapakari rānei i tō rātou reo. Hāunga tērā, me ō rātou ngana anō ki te kawe i te reo Māori i te kāinga, ko ngā mātua kāore anō kia tino eke te reo ā-waha ka mate i te pōraruraru, te pōkaikaha, te āwangawanga, me te kaha papare a ngā tamariki e pakeke haere ana. Nā runga i tērā, me te take anō hoki he ruarua noa iho ngā wāhi o te hapori whānui i ēnei rā kia taea te reo Māori te rere noa, kua whakapuāwaitia e te tokomaha o tēnei rōpū ētahi rautaki hei ārahi i ngā tamariki me ngā mokopuna i ā rātou e pakeke haere ana, kia mārama rātou ki ngā whakahere tinana a te marea kia whai wāhi ai rātou ki te ako i te reo, me ngā here e haere kōtui ana ki ērā āhuatanga, kia whakanuia, kia utua hoki ngā tamariki i runga anō i ngā whakatutukitanga reo, kia manaakitia hoki rātou ki te whai wāhi anō ki ngā horopaki reo Māori. Hei konei ka ākina rātou ki te uru ki ngā kapa haka me ngā tino kaupapa anō o te ao Māori e whakatairanga nei i te reo. Anō hoki, ka whakahauhautia kia piritata ki ā rātou hoa me ō rātou whanaunga e tino mōhio ki te reo, me te whakauru hoki ki ngā mahinga marae. Waihoki, ka pōwhiritia te hunga matatau ki te reo ki te toro mai ki ō rātou kāinga (nā reira, me whakapau kaha anō ngā mātua ki te whakahoahoa, ki te patipati, ērā tāngata kia whakaae mai ki te noho ki te taha o ngā tamariki whakaputa kōrero ai). Koinei ngā mea ka taea ai e ngā mātua katoa, e ngā kaitiaki katoa, ahakoa kei hea te tohungatanga o tō rātou reo.  Mā reira, ka whai wāhi tonu, ka whakamanahia tonu tēnei hunga e pōhēhē nei pea he iti noa iho tā rātou hei koha atu ki te whakarauoratanga o te reo. Nō reira, hāunga rā te whakaaro he nui ngā mātua me ngā kaitiaki tamariki i tēnei wā e kore e tino whai wāhi ki te tukunga iho o te reo i te kāinga, ehara i te mea he kore noa iho tā rātou hei koha atu ki tēnei kaupapa whakahirahira.

text: Reclaiming the Māori language for future generations: Flax root perspectives. Tīkina te mana o te reo Māori: Te pūtaketanga o te pā harakeke Using a combination of semi-structured interviews, focus group discussion and questionnaires (designed to elicit as many comments as possible), this thesis explores, through their own voices, the attitudes and practices of a group of people, mainly Māori but including a few Pākehā (non-Māori) who are attempting to reclaim te reo Māori (the Māori language), for themselves, their families and, above all, their children and grandchildren. Many of them were brought up in a context in which one or more parents, caregivers or relatives spoke te reo Māori fluently but few were given the opportunity to acquire the language naturally in infancy, generally because of a desire to protect them from the discrimination suffered by their elders. Those who were brought up to speak te reo Māori often suffered from language attrition at a time when the English language began to feature prominently in their lives. A few have attended kōhanga reo and kura kaupapa Māori. Many have attended courses in the Māori language and culture, often at considerable personal cost. Some have achieved their dream of becoming fluent speakers of the language; some have suffered frustration and disappointment. Whatever their own experiences, almost all of them want their children and grandchildren to be fluent speakers of the language, believing that this will give them confidence and a genuine sense of identity and belonging. Although the majority are committed to using te reo Māori as much as possible at home, especially when speaking to their children and grandchildren, most experience difficulties in doing so. These difficulties relate, in general, to their own lack of confidence and/or limited competence in the language, the fact that some of their friends and/or members of their immediate or extended family are monolingual in English, and resistance from some of the children, particularly as they grow older and are increasingly influenced by the dominant language and culture. Among those involved in this research project, there was widespread awareness of the importance of inter-generational transmission of te reo Māori and evidence of considerable commitment to learning the language and/or improving their existing competence in it. However, although the attempts of these adults to use te reo Māori in the home are clearly of considerable importance, they often, where they lacked a high level of oral proficiency, met with confusion, frustration, tension and resistance as their children grew older. This, combined with the fact that there are currently so few domains in society at large in which the language can be used naturally, has led many of them to develop strategies aimed at ensuring that their children and grandchildren, as they grow towards adulthood (a) appreciate the sacrifices made by so many in order to give them the opportunity to learn the language and the responsibilities associated with these sacrifices, (b) are recognised and rewarded for their linguistic achievements, and (c) are encouraged and assisted to involve themselves in contexts where they can use the language. This includes encouraging them to become involved in kapa haka and other culturally significant activities in which the language plays a prominent part, promoting as much engagement as possible with friends and whānau who have a high level of proficiency in the language (including involving them and their friends in marae-based activities), and inviting into their homes people who are fluent speakers (which sometimes involves a conscious effort on the part of the adults to cement friendships with fluent speakers and to encourage them to interact with their children). These are things which all parents and caregivers can do, irrespective of their own language competence. 

In doing these things, those who currently feel that they have little to offer in relation to the revitalization of the language can experience a genuine sense of involvement and empowerment. Accepting that there are currently many parents and caregivers who cannot realistically become involved in genuine inter-generational transmission of the language in the home does not mean accepting that they have nothing to offer. 

Mā te kōwhiringa o ngā uiuitanga hangā ngāwari, te whiriwhiri ā rōpū kanohi, me te puka patapātai (hei tōngia mai ngā kōrero whānui kē atu o tēnā, o tēnā), ka whakatewhatewha te tuhinga nei i ngā waiaro me ngā ritenga o tētehi rōpū e ngana ana ki te haumanu i te reo Māori hei taonga mō rātou ko ō rātou whānau, ā, mō ā rātou tamariki, mokopuna hoki. Te nuinga o te hunga nei he Māori; he tokoiti anō he Pākehā. He tokomaha o rātou i tipu ake i roto i te horopaki o te reo Māori, arā, kotahi neke atu o ō rātou mātua rānei, kaitiaki rānei, whanaunga rānei he matatau ki te reo Māori. Ahakoa rā, kāore te nuinga i whāngaihia ki te reo i ā rātou e pēpi ana, kei whakapai kanohitia pērā i ō rātou tūpuna. Ko rātou te hunga i tipu reo Māori mai, ka memeha haere tō rātou reo nō te tino putanga ake o te reo Pākehā ki ō rātou ao. He tokoiti o tēnei rōpu i kuraina ki te kōhanga reo me te kura kaupapa Māori; he tokomaha anō i whai wāhi ki ngā akoranga reo Māori me ōna tikanga, hāunga rā te nui o te nama. Ko ētehi, kua ea ngā wawata, kua matatau ki te reo; ko ētehi atu anō, kua pāngia kētia e te hōhā me te hēmanawatanga. Heoi, ahakoa ngā wheako ake o tēnā, o tēnā, he hiahia nō te nuinga kia matatau ā rātou tamariki me ā rātou mokopuna ki te reo, kia tū pakari ai, kia tū Māori ai ki tēnei ao. Te nuinga o tēnei rōpū he manawanui ki te kōrero Māori i te kāinga i te nuinga o te wā, koia anō rā i ā rātou e kōrero ana ki ā rātou tamariki me ā rātou mokopuna. Heoi anō, kei reira anō ngā papatoieketanga, e pā ana ki ō rātou ake tītengi rānei, ki te takarepatanga o tō rātou reo rānei, me te mōhio anō ko ētahi o ō rātou hoa, whānau, whānau whānui anō hoki, he reo tahi kē, arā, ko te reo Pākehā te reo kawe. Anō hoki, ko ētahi o ngā tamariki, i ā rātou e pakeke haere ana ka kaha papare i te reo Māori, ka whakawaia kētia rātou e te reo Pākehā me ōna tikanga. I waenganui i te hunga i whai wāhi ki tēnei kaupapa rangahau kua kitea he mārama pū te nuinga ki te tino hiranga o te tuku ihotanga o te reo; kua kitea hoki tō rātou kaingākau nui ki te ako i te reo, ki te whakapakari rānei i tō rātou reo. Hāunga tērā, me ō rātou ngana anō ki te kawe i te reo Māori i te kāinga, ko ngā mātua kāore anō kia tino eke te reo ā-waha ka mate i te pōraruraru, te pōkaikaha, te āwangawanga, me te kaha papare a ngā tamariki e pakeke haere ana. Nā runga i tērā, me te take anō hoki he ruarua noa iho ngā wāhi o te hapori whānui i ēnei rā kia taea te reo Māori te rere noa, kua whakapuāwaitia e te tokomaha o tēnei rōpū ētahi rautaki hei ārahi i ngā tamariki me ngā mokopuna i ā rātou e pakeke haere ana, kia mārama rātou ki ngā whakahere tinana a te marea kia whai wāhi ai rātou ki te ako i te reo, me ngā here e haere kōtui ana ki ērā āhuatanga, kia whakanuia, kia utua hoki ngā tamariki i runga anō i ngā whakatutukitanga reo, kia manaakitia hoki rātou ki te whai wāhi anō ki ngā horopaki reo Māori. Hei konei ka ākina rātou ki te uru ki ngā kapa haka me ngā tino kaupapa anō o te ao Māori e whakatairanga nei i te reo. Anō hoki, ka whakahauhautia kia piritata ki ā rātou hoa me ō rātou whanaunga e tino mōhio ki te reo, me te whakauru hoki ki ngā mahinga marae. Waihoki, ka pōwhiritia te hunga matatau ki te reo ki te toro mai ki ō rātou kāinga (nā reira, me whakapau kaha anō ngā mātua ki te whakahoahoa, ki te patipati, ērā tāngata kia whakaae mai ki te noho ki te taha o ngā tamariki whakaputa kōrero ai). Koinei ngā mea ka taea ai e ngā mātua katoa, e ngā kaitiaki katoa, ahakoa kei hea te tohungatanga o tō rātou reo.  Mā reira, ka whai wāhi tonu, ka whakamanahia tonu tēnei hunga e pōhēhē nei pea he iti noa iho tā rātou hei koha atu ki te whakarauoratanga o te reo. Nō reira, hāunga rā te whakaaro he nui ngā mātua me ngā kaitiaki tamariki i tēnei wā e kore e tino whai wāhi ki te tukunga iho o te reo i te kāinga, ehara i te mea he kore noa iho tā rātou hei koha atu ki tēnei kaupapa whakahirahira.

year: 2014

title: Occlusion prediction for kiwifruit yield estimation

authors: Seabright, Matthew James

subjects: kiwifruit

abstract: Kiwifruit is very important to the New Zealand economy, bringing in NZ$2.39 billion in the 2017/2018 season and projected to grow to NZ$4.5 billion by 2025. Every season, the expected yield from each orchard is estimated. These estimates are used for both on-orchard decisions regarding thinning and spraying, and industry level decisions regarding export pricing, supply agreements, labour requirements, packaging quantities and more. The current method for yield estimation is manual and prone to errors. In the 2016/17 growing season, green kiwifruit estimates were 5.9% lower than actual harvest yield, resulting in over 5 million trays (approximately 18,000 tons) of fruit being disposed of.

An automated system could reduce errors saving the industry significant amounts of money. Such a system could realise other benefits such as providing more granular information on orchard performance to growers and increasing labour efficiency and crop uniformity via targeted labour. Other automated fruit yield estimation systems have been developed but have suffered from sub-optimal performance due to occlusion of fruit. The work presented here introduces a system that has been developed with the aim of minimising occlusion where possible and employs an occlusion prediction model to account for remaining occlusion. The system utilises stereo vision, a 3D lidar unit, an inertial measurement unit and LED lighting mounted on an all terrain vehicle (ATV).
Data is captured across 16 maturity areas, consisting of 33.9 Ha of commercial kiwifruit orchards. A simultaneous localisation and mapping system is used to locate the ATV within the orchard. A convolutional neural network detects kiwifruit, which are localised via stereo triangulation. Individual fruit are tracked through overlapping images to reduce occlusion while ensuring no double counting. Fruit are counted and an occlusion prediction model is applied to account for the unseen fruit.

The system is able to predict orchard scale fruit yield with a mean absolute percentage error of 0.68%. This error rate was obtained from an independent test dataset and ground truth data obtained from a commercial kiwifruit packhouse. The system can also generate visualisations of orchards showing all individual detected fruit in 3D, fruit density maps and canopy density maps. The ability of the system to predict yield with high accuracy and at orchard scale sets it apart from previous work. It is also the largest scale study currently known, consisting of over 15 million fruit.

text: Occlusion prediction for kiwifruit yield estimation Kiwifruit is very important to the New Zealand economy, bringing in NZ$2.39 billion in the 2017/2018 season and projected to grow to NZ$4.5 billion by 2025. Every season, the expected yield from each orchard is estimated. These estimates are used for both on-orchard decisions regarding thinning and spraying, and industry level decisions regarding export pricing, supply agreements, labour requirements, packaging quantities and more. The current method for yield estimation is manual and prone to errors. In the 2016/17 growing season, green kiwifruit estimates were 5.9% lower than actual harvest yield, resulting in over 5 million trays (approximately 18,000 tons) of fruit being disposed of.

An automated system could reduce errors saving the industry significant amounts of money. Such a system could realise other benefits such as providing more granular information on orchard performance to growers and increasing labour efficiency and crop uniformity via targeted labour. Other automated fruit yield estimation systems have been developed but have suffered from sub-optimal performance due to occlusion of fruit. The work presented here introduces a system that has been developed with the aim of minimising occlusion where possible and employs an occlusion prediction model to account for remaining occlusion. The system utilises stereo vision, a 3D lidar unit, an inertial measurement unit and LED lighting mounted on an all terrain vehicle (ATV).
Data is captured across 16 maturity areas, consisting of 33.9 Ha of commercial kiwifruit orchards. A simultaneous localisation and mapping system is used to locate the ATV within the orchard. A convolutional neural network detects kiwifruit, which are localised via stereo triangulation. Individual fruit are tracked through overlapping images to reduce occlusion while ensuring no double counting. Fruit are counted and an occlusion prediction model is applied to account for the unseen fruit.

The system is able to predict orchard scale fruit yield with a mean absolute percentage error of 0.68%. This error rate was obtained from an independent test dataset and ground truth data obtained from a commercial kiwifruit packhouse. The system can also generate visualisations of orchards showing all individual detected fruit in 3D, fruit density maps and canopy density maps. The ability of the system to predict yield with high accuracy and at orchard scale sets it apart from previous work. It is also the largest scale study currently known, consisting of over 15 million fruit.

year: 2020