L. Comba | Università degli Studi di Torino (original) (raw)

Papers by L. Comba

Research paper thumbnail of Robotic solutions for pot-plant nurseries

Billion of pots are produced every year in Europe. In many Countries, in particular in Mediterran... more Billion of pots are produced every year in Europe. In many Countries, in particular in Mediterranean area, pot plant nurseries involve a lot of manpower and the degree of mechanization is still low, affecting the competiveness of farms. Moreover, most operations performed on potted-plant are extremely repetitive (e.g. pots handling, trimming, granular fertilization) and some tasks are critical for operator’s safety (e.g. spray applications). A number of automatic machines and implements are available on the market, but in most cases the installation of fixed and expansive structures is required. The introduction of small multipurpose robotic platforms, able to navigate autonomously along pot rows, would reduce the manpower requirement improving, at the same time, work safety. The design and the kinematic study of an autonomous robotic platform conceived to operate in pot plant nurseries is presented in this paper. The robot is based on a four drive-and-steering wheels vehicle design...

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Research paper thumbnail of Design of an innovative plant for fast freezing of potato dumplings

The design of an innovative plant for fast freezing of potato dumplings at temperatures much lowe... more The design of an innovative plant for fast freezing of potato dumplings at temperatures much lower than traditional freezing plants is presented in this study. The designed plant is constituted by two separate loops: the first loop, where the cooling energy is obtained at low temperature, is based on a reversed Brayton cycle while the second loop, where the dumplings are frozen, is a forced-air freezer room. Optimal plant parameters, such as temperature and velocity of the freezing medium (air), to obtain the required fast freezing time of dumplings are evaluated. Depending on the requested freezing time and on the mass per hour of dumplings to be processed, the suitable plant solution can be identified and finely designed. The proposed solution overcomes limits of traditional freezing plants, such as ones operated by vapour compression cycles, which cannot reach such low temperatures without exceeding in complexity and number of stages. For this reason, the plant is proved to be a ...

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Research paper thumbnail of 34. Semantic interpretation of multispectral maps for precision agriculture: a machine learning approach

Precision agriculture ’21, 2021

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Research paper thumbnail of Browning kinetics evaluation using image processing techniques

Colour changes in peach 'Extra' jam owing to thermal treatment at different temperatures ... more Colour changes in peach 'Extra' jam owing to thermal treatment at different temperatures (80°C, 85°C, 90°C and 95°C) were investigated. Browning kinetics were assessed on jam samples brought just after concentration phase in order to determine the effect of the thermal treatments, subsequent to this step, that take place during the production process (hot bottling, final pasteurization). Colour measurements were performed applying image processing techniques on images acquired through a flatbed scanner as well as by traditional measurements with colorimeter. CIELAB colour space was considered using lightness (L*), colour difference (ΔE) and a* parameters to describe browning evolution with time at the considered temperatures. A first order kinetic model was applied to L* changes. A kinetic model based on a two-stage mechanism was employed to describe a* evolution. Colour difference was modeled with both kinetics even if the two-stage model better describe the evolution of th...

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Research paper thumbnail of Neural network clustering for crops thermal mapping

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Research paper thumbnail of A method for crop water status evaluation by thermal imagery for precision viticulture: preliminary results

Acta Horticulturae, 2021

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Research paper thumbnail of Performance analysis of a tractor - power harrow system under different working conditions

Biosystems Engineering

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Research paper thumbnail of UAV and Machine Learning Based Refinement of a Satellite-Driven Vegetation Index for Precision Agriculture

Sensors

Precision agriculture is considered to be a fundamental approach in pursuing a low-input, high-ef... more Precision agriculture is considered to be a fundamental approach in pursuing a low-input, high-efficiency, and sustainable kind of agriculture when performing site-specific management practices. To achieve this objective, a reliable and updated description of the local status of crops is required. Remote sensing, and in particular satellite-based imagery, proved to be a valuable tool in crop mapping, monitoring, and diseases assessment. However, freely available satellite imagery with low or moderate resolutions showed some limits in specific agricultural applications, e.g., where crops are grown by rows. Indeed, in this framework, the satellite’s output could be biased by intra-row covering, giving inaccurate information about crop status. This paper presents a novel satellite imagery refinement framework, based on a deep learning technique which exploits information properly derived from high resolution images acquired by unmanned aerial vehicle (UAV) airborne multispectral sensor...

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Research paper thumbnail of Leaf Area Index evaluation in vineyards using 3D point clouds from UAV imagery

Precision Agriculture

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Research paper thumbnail of Relation between energy use and indoor thermal environment in animal husbandry: a case study

E3S Web of Conferences

Climate control is of the foremost importance in structures for intensive animal rearing because ... more Climate control is of the foremost importance in structures for intensive animal rearing because many animals (e.g. pigs and broilers) tolerate a small range of climate conditions (mainly air temperature and relative humidity) that may differ considerably from the outdoor environment. For this reason, the indoor climate in the majority of structures for animal husbandry is guaranteed by HVAC systems. On the one hand, the use of mechanical systems makes it possible to avoid production risks due to the unpredictability of the outdoor weather conditions and to maximize the feed efficiency, with positive effects on both the animal welfare and farm profit. On the other hand, the use of HVAC entails not negligible thermal and electrical energy consumptions. In literature, few data about the real thermo-hygrometric conditions and energy consumption of animal houses are present. In this work (in the framework of the EPAnHaus – Energy Performance certification of Animal Houses –project), the...

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Research paper thumbnail of Cost-effective visual odometry system for vehicle motion control in agricultural environments

Computers and Electronics in Agriculture

In precision agriculture, innovative cost-effective technologies and new improved solutions, aime... more In precision agriculture, innovative cost-effective technologies and new improved solutions, aimed at making operations and processes more reliable, robust and economically viable, are still needed. In this context, robotics and automation play a crucial role, with particular reference to unmanned vehicles for crop monitoring and site-specific operations. However, unstructured and irregular working environments, such as agricultural scenarios, require specific solutions regarding positioning and motion control of autonomous vehicles. In this paper, a reliable and cost-effective monocular visual odometry system, properly calibrated for the localisation and navigation of tracked vehicles on agricultural terrains, is presented. The main contribution of this work is the design and implementation of an enhanced image processing algorithm, based on the cross-correlation approach. It was specifically developed to use a simplified hardware and a low complexity mechanical system, without compromising performance. By providing sub-pixel results, the presented algorithm allows to exploit low-resolution images, thus obtaining high accuracy in motion estimation with short computing time. The results, in terms of odometry accuracy and processing time, achieved during the in-field experimentation campaign on several terrains proved the effectiveness of the proposed method and its fitness for automatic control solutions in precision agriculture applications.

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Research paper thumbnail of Comparison of Satellite and UAV-Based Multispectral Imagery for Vineyard Variability Assessment

Remote Sensing

In agriculture, remotely sensed data play a crucial role in providing valuable information on cro... more In agriculture, remotely sensed data play a crucial role in providing valuable information on crop and soil status to perform effective management. Several spectral indices have proven to be valuable tools in describing crop spatial and temporal variability. In this paper, a detailed analysis and comparison of vineyard multispectral imagery, provided by decametric resolution satellite and low altitude Unmanned Aerial Vehicle (UAV) platforms, is presented. The effectiveness of Sentinel-2 imagery and of high-resolution UAV aerial images was evaluated by considering the well-known relation between the Normalised Difference Vegetation Index (NDVI) and crop vigour. After being pre-processed, the data from UAV was compared with the satellite imagery by computing three different NDVI indices to properly analyse the unbundled spectral contribution of the different elements in the vineyard environment considering: (i) the whole cropland surface; (ii) only the vine canopies; and (iii) only th...

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Research paper thumbnail of Unsupervised detection of vineyards by 3D point-cloud UAV photogrammetry for precision agriculture

Computers and Electronics in Agriculture

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Research paper thumbnail of The influence of food composition and tag orientation on UHF RF IDentification

Journal of Food Engineering

Ultra-high frequency (UHF) radio frequency (RF) labelling is considered to be one of the most pro... more Ultra-high frequency (UHF) radio frequency (RF) labelling is considered to be one of the most promising techniques for automatic identification through all food supply chain phases. However, the efficacy of RF IDentification (RFID) systems has proven critical for some food products. In this paper the role of the composition and the temperature of the food product and of the mutual label-reader orientation on identification performances is investigated. For this purpose, basic food constituents, prepared as solutions (salts, sugars, organic acids and ethanol) at different concentrations and temperatures, were considered and then the identification results were compared to those obtained from whole food products. The results show how the reading performances of UHF RFID systems are influenced by the considered parameters. The reading ranges for the identification of critical food products by UHF RFID systems can be estimated and then improved by considering the composition of the food product directly from the design phase.

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Research paper thumbnail of Individual plant definition and missing plant characterization in vineyards from high-resolution UAV imagery

European Journal of Remote Sensing

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Research paper thumbnail of Steam batch thermal processes in unsteady state conditions: Modelling and application to a case study in the food industry

Applied Thermal Engineering, 2017

Many industrial processes require high amounts of steam. Design and operation of steam plants are... more Many industrial processes require high amounts of steam. Design and operation of steam plants are particularly complex when the steam supply is required for short periods and with a varying time schedules. To fulfil the discontinuous needs of steam users, avoiding the steam boiler oversizing to the peak value of the steam request, a thermal energy storage (TES) system can be adopted. The proper sizing of TES systems, which, in this application, is constituted by a steam accumulator vessel installed between the steam generator and the consumer, cannot be based on the sole initial and final state conditions of the steam storage, since a performance prediction of the process time-evolution is also required. In this paper, a model of steam batch processes for industrial thermal treatments, able to describe unsteady operative conditions, is presented. More in detail, a three-stage steam plant, with a sequentially interconnected steam boiler, steam accumulator and processing tank, has been considered. The dynamic model of the charging and discharging processes of the steam accumulator has been applied to a real case study in the food industry: the batch debacterisation process of cocoa beans. Nevertheless, the obtained results can be profitably employed in the design and the performance assessments of a wide set of applications involving the steam processing fluid, such as desalination plants, solar thermal power plants, retorts, steam ovens and others.

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Research paper thumbnail of Case Studies in Food Freezing at Very Low Temperature

Energy Procedia, 2016

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Research paper thumbnail of Modeling techniques for the control of thermal exchanges in mixed continuous-discontinuous flow food plants

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Research paper thumbnail of Innovazione nelle linee di per il packaging secondario

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Research paper thumbnail of Robot ensembles for grafting herbaceous crops

Biosystems Engineering, 2016

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Research paper thumbnail of Robotic solutions for pot-plant nurseries

Billion of pots are produced every year in Europe. In many Countries, in particular in Mediterran... more Billion of pots are produced every year in Europe. In many Countries, in particular in Mediterranean area, pot plant nurseries involve a lot of manpower and the degree of mechanization is still low, affecting the competiveness of farms. Moreover, most operations performed on potted-plant are extremely repetitive (e.g. pots handling, trimming, granular fertilization) and some tasks are critical for operator’s safety (e.g. spray applications). A number of automatic machines and implements are available on the market, but in most cases the installation of fixed and expansive structures is required. The introduction of small multipurpose robotic platforms, able to navigate autonomously along pot rows, would reduce the manpower requirement improving, at the same time, work safety. The design and the kinematic study of an autonomous robotic platform conceived to operate in pot plant nurseries is presented in this paper. The robot is based on a four drive-and-steering wheels vehicle design...

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Research paper thumbnail of Design of an innovative plant for fast freezing of potato dumplings

The design of an innovative plant for fast freezing of potato dumplings at temperatures much lowe... more The design of an innovative plant for fast freezing of potato dumplings at temperatures much lower than traditional freezing plants is presented in this study. The designed plant is constituted by two separate loops: the first loop, where the cooling energy is obtained at low temperature, is based on a reversed Brayton cycle while the second loop, where the dumplings are frozen, is a forced-air freezer room. Optimal plant parameters, such as temperature and velocity of the freezing medium (air), to obtain the required fast freezing time of dumplings are evaluated. Depending on the requested freezing time and on the mass per hour of dumplings to be processed, the suitable plant solution can be identified and finely designed. The proposed solution overcomes limits of traditional freezing plants, such as ones operated by vapour compression cycles, which cannot reach such low temperatures without exceeding in complexity and number of stages. For this reason, the plant is proved to be a ...

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Research paper thumbnail of 34. Semantic interpretation of multispectral maps for precision agriculture: a machine learning approach

Precision agriculture ’21, 2021

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Browning kinetics evaluation using image processing techniques

Colour changes in peach 'Extra' jam owing to thermal treatment at different temperatures ... more Colour changes in peach 'Extra' jam owing to thermal treatment at different temperatures (80°C, 85°C, 90°C and 95°C) were investigated. Browning kinetics were assessed on jam samples brought just after concentration phase in order to determine the effect of the thermal treatments, subsequent to this step, that take place during the production process (hot bottling, final pasteurization). Colour measurements were performed applying image processing techniques on images acquired through a flatbed scanner as well as by traditional measurements with colorimeter. CIELAB colour space was considered using lightness (L*), colour difference (ΔE) and a* parameters to describe browning evolution with time at the considered temperatures. A first order kinetic model was applied to L* changes. A kinetic model based on a two-stage mechanism was employed to describe a* evolution. Colour difference was modeled with both kinetics even if the two-stage model better describe the evolution of th...

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Research paper thumbnail of Neural network clustering for crops thermal mapping

Bookmarks Related papers MentionsView impact

Research paper thumbnail of A method for crop water status evaluation by thermal imagery for precision viticulture: preliminary results

Acta Horticulturae, 2021

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Research paper thumbnail of Performance analysis of a tractor - power harrow system under different working conditions

Biosystems Engineering

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Research paper thumbnail of UAV and Machine Learning Based Refinement of a Satellite-Driven Vegetation Index for Precision Agriculture

Sensors

Precision agriculture is considered to be a fundamental approach in pursuing a low-input, high-ef... more Precision agriculture is considered to be a fundamental approach in pursuing a low-input, high-efficiency, and sustainable kind of agriculture when performing site-specific management practices. To achieve this objective, a reliable and updated description of the local status of crops is required. Remote sensing, and in particular satellite-based imagery, proved to be a valuable tool in crop mapping, monitoring, and diseases assessment. However, freely available satellite imagery with low or moderate resolutions showed some limits in specific agricultural applications, e.g., where crops are grown by rows. Indeed, in this framework, the satellite’s output could be biased by intra-row covering, giving inaccurate information about crop status. This paper presents a novel satellite imagery refinement framework, based on a deep learning technique which exploits information properly derived from high resolution images acquired by unmanned aerial vehicle (UAV) airborne multispectral sensor...

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Research paper thumbnail of Leaf Area Index evaluation in vineyards using 3D point clouds from UAV imagery

Precision Agriculture

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Research paper thumbnail of Relation between energy use and indoor thermal environment in animal husbandry: a case study

E3S Web of Conferences

Climate control is of the foremost importance in structures for intensive animal rearing because ... more Climate control is of the foremost importance in structures for intensive animal rearing because many animals (e.g. pigs and broilers) tolerate a small range of climate conditions (mainly air temperature and relative humidity) that may differ considerably from the outdoor environment. For this reason, the indoor climate in the majority of structures for animal husbandry is guaranteed by HVAC systems. On the one hand, the use of mechanical systems makes it possible to avoid production risks due to the unpredictability of the outdoor weather conditions and to maximize the feed efficiency, with positive effects on both the animal welfare and farm profit. On the other hand, the use of HVAC entails not negligible thermal and electrical energy consumptions. In literature, few data about the real thermo-hygrometric conditions and energy consumption of animal houses are present. In this work (in the framework of the EPAnHaus – Energy Performance certification of Animal Houses –project), the...

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Cost-effective visual odometry system for vehicle motion control in agricultural environments

Computers and Electronics in Agriculture

In precision agriculture, innovative cost-effective technologies and new improved solutions, aime... more In precision agriculture, innovative cost-effective technologies and new improved solutions, aimed at making operations and processes more reliable, robust and economically viable, are still needed. In this context, robotics and automation play a crucial role, with particular reference to unmanned vehicles for crop monitoring and site-specific operations. However, unstructured and irregular working environments, such as agricultural scenarios, require specific solutions regarding positioning and motion control of autonomous vehicles. In this paper, a reliable and cost-effective monocular visual odometry system, properly calibrated for the localisation and navigation of tracked vehicles on agricultural terrains, is presented. The main contribution of this work is the design and implementation of an enhanced image processing algorithm, based on the cross-correlation approach. It was specifically developed to use a simplified hardware and a low complexity mechanical system, without compromising performance. By providing sub-pixel results, the presented algorithm allows to exploit low-resolution images, thus obtaining high accuracy in motion estimation with short computing time. The results, in terms of odometry accuracy and processing time, achieved during the in-field experimentation campaign on several terrains proved the effectiveness of the proposed method and its fitness for automatic control solutions in precision agriculture applications.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Comparison of Satellite and UAV-Based Multispectral Imagery for Vineyard Variability Assessment

Remote Sensing

In agriculture, remotely sensed data play a crucial role in providing valuable information on cro... more In agriculture, remotely sensed data play a crucial role in providing valuable information on crop and soil status to perform effective management. Several spectral indices have proven to be valuable tools in describing crop spatial and temporal variability. In this paper, a detailed analysis and comparison of vineyard multispectral imagery, provided by decametric resolution satellite and low altitude Unmanned Aerial Vehicle (UAV) platforms, is presented. The effectiveness of Sentinel-2 imagery and of high-resolution UAV aerial images was evaluated by considering the well-known relation between the Normalised Difference Vegetation Index (NDVI) and crop vigour. After being pre-processed, the data from UAV was compared with the satellite imagery by computing three different NDVI indices to properly analyse the unbundled spectral contribution of the different elements in the vineyard environment considering: (i) the whole cropland surface; (ii) only the vine canopies; and (iii) only th...

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Research paper thumbnail of Unsupervised detection of vineyards by 3D point-cloud UAV photogrammetry for precision agriculture

Computers and Electronics in Agriculture

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Research paper thumbnail of The influence of food composition and tag orientation on UHF RF IDentification

Journal of Food Engineering

Ultra-high frequency (UHF) radio frequency (RF) labelling is considered to be one of the most pro... more Ultra-high frequency (UHF) radio frequency (RF) labelling is considered to be one of the most promising techniques for automatic identification through all food supply chain phases. However, the efficacy of RF IDentification (RFID) systems has proven critical for some food products. In this paper the role of the composition and the temperature of the food product and of the mutual label-reader orientation on identification performances is investigated. For this purpose, basic food constituents, prepared as solutions (salts, sugars, organic acids and ethanol) at different concentrations and temperatures, were considered and then the identification results were compared to those obtained from whole food products. The results show how the reading performances of UHF RFID systems are influenced by the considered parameters. The reading ranges for the identification of critical food products by UHF RFID systems can be estimated and then improved by considering the composition of the food product directly from the design phase.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Individual plant definition and missing plant characterization in vineyards from high-resolution UAV imagery

European Journal of Remote Sensing

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Research paper thumbnail of Steam batch thermal processes in unsteady state conditions: Modelling and application to a case study in the food industry

Applied Thermal Engineering, 2017

Many industrial processes require high amounts of steam. Design and operation of steam plants are... more Many industrial processes require high amounts of steam. Design and operation of steam plants are particularly complex when the steam supply is required for short periods and with a varying time schedules. To fulfil the discontinuous needs of steam users, avoiding the steam boiler oversizing to the peak value of the steam request, a thermal energy storage (TES) system can be adopted. The proper sizing of TES systems, which, in this application, is constituted by a steam accumulator vessel installed between the steam generator and the consumer, cannot be based on the sole initial and final state conditions of the steam storage, since a performance prediction of the process time-evolution is also required. In this paper, a model of steam batch processes for industrial thermal treatments, able to describe unsteady operative conditions, is presented. More in detail, a three-stage steam plant, with a sequentially interconnected steam boiler, steam accumulator and processing tank, has been considered. The dynamic model of the charging and discharging processes of the steam accumulator has been applied to a real case study in the food industry: the batch debacterisation process of cocoa beans. Nevertheless, the obtained results can be profitably employed in the design and the performance assessments of a wide set of applications involving the steam processing fluid, such as desalination plants, solar thermal power plants, retorts, steam ovens and others.

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Case Studies in Food Freezing at Very Low Temperature

Energy Procedia, 2016

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Modeling techniques for the control of thermal exchanges in mixed continuous-discontinuous flow food plants

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Innovazione nelle linee di per il packaging secondario

Bookmarks Related papers MentionsView impact

Research paper thumbnail of Robot ensembles for grafting herbaceous crops

Biosystems Engineering, 2016

Bookmarks Related papers MentionsView impact