Visible and Hyperspectral Imaging Systems for the Detection and Discrimination of Mechanical and Microbiological Damage of Mushrooms

Horticultural products such as mushrooms are exposed to environmental conditions during their postharvest life, which may affect product quality. Loss of whiteness during storage is particularly important in the mushroom industry. Rough handling and distribution, fruiting body senescence and bacterial infections are among the main causes of mushroom discolouration. The aim of this work was to study the use of visible and hyperspectral imaging (HSI) systems for the detection and discrimination of mechanical and microbiological damage of mushrooms. This piece of research involved a) monitoring the browning of mushroom with visible computer imaging systems, b) investigating the effect of mechanical damage on the kinetics of enzymes responsible for mushroom browning, c) exploring the potential use of Vis-NIR HSI to predict PPO activity in mushroom caps and d) studying the potential application of Vis-NIR HSI for microbial and viral detection on mushroom caps and for their discrimination from mechanical damage. Results presented in this thesis show that the efficacy of commercial webcams was limited in the detection of mechanical damage on mushroom caps. Damage increased the activity of PPOs on mushroom pileipellis, but the effect of the extent of damage was not significant at the levels of study. Vis-NIR HSI showed some potential as a tool to estimate the activity of PPO enzymes on mushroom caps. The combination of HSI with chemometric tools allowed for the differentiation of mechanically and microbiologically damaged mushroom classes. Results from this study could be used for developing non-destructive monitoring systems for mechanical and microbiological damage detection and discrimination. The potential application of such systems as on-line process analytical tools would facilitate rapid assessment of mushroom quality.

Visible Near-Infrared Hyperspectral Imaging for the Identification and Discrimination of Brown Blotch Disease on Mushroom (Agaricus bisporus) Caps

Brown blotch, caused by pathogenic Pseudomonas tolaasii (P. tolaasii), is the most problematic bacterial disease in Agaricus bisporus mushrooms. Although it does not cause any health problems, it reduces the consumer appeal of mushrooms in the market place, generating important economical losses worldwide. Hyperspectral imaging (HSI) is a non-destructive technique that combines imaging and spectroscopy to obtain information from a sample. The objective of this study was to investigate the use of HSI for brown blotch identification and discrimination from mechanical damage on mushrooms. Hyperspectral images of mushrooms subjected to i) no treatment, ii) mechanical damage or iii) microbiological spoilage were taken during storage and spectra representing each of the classes were selected. Partial least squares- discriminant analysis (PLS-DA) was carried out in two steps: i) discrimination between undamaged and damaged mushrooms and ii) discrimination between damage sources (i.e. mechanical or microbiological). The models were applied at a pixel level and a decision tree was used to classify mushrooms into one of the aforementioned classes. A correct classification of \u3e95% was achieved. Results from this study could be used for the development of a sensor to detect and classify mushroom damage of mechanical and microbial origin, which would facilitate the industry to make rapid and automated decisions to discard produce of poor marketability

Recent Advances and Applications of Hyperspectral Imaging for Fruit and Vegetable Quality Assessment

Hyperspectral imaging systems are starting to be used as a scientific tool for food quality assessment. A typical hyperspectral image is composed of a set of a relatively wide range of monochromatic images corresponding to continuous wavelengths that normally contain redundant information or may exhibit a high degree of correlation. In addition, computation of the classifiers used to deal with the data obtained from the images can become excessively complex and time-consuming for such high-dimensional datasets, and this makes it difficult to incorporate such systems into an industry that demands standard protocols or high-speed processes. Therefore, recent works have focused on the development of new systems based on this technology that are capable of analysing quality features that cannot be inspected using visible imaging. Many of those studies have also centred on finding new statistical techniques to reduce the hyperspectral images to multispectral ones, which are easier to implement in automatic, non-destructive systems. This article reviews recent works that use hyperspectral imaging for the inspection of fruit and vegetables. It explains the different technologies available to acquire the images and their use for the non-destructive inspection of the internal and external features of these products. Particular attention is paid to the works aimed at reducing the dimensionality of the images, with details of the statistical techniques most commonly used for this task

Development of an Autonomous Robotic Mushroom Harvester

The process of development of a new robot is one of the modern technological arts. This process involves multiple complex steps and recursive approach. In this project, a solution for automatic harvesting of mushrooms is developed. In order to design an effective solution, it is necessary to explore and take into consideration the limitations of grasping very soft and fragile objects (particularly mushrooms). We will elaborate several strategies of picking and analyze each strategy to formulate the design requirements, develop a solution, and finally, evaluate the efficiency of the proposed solution in actual farm conditions for real mushrooms. The mushroom farm used in our study utilizes Dutch shelving systems, which pose stringent space requirements on the construction. The main challenge in this project is the development of a robot with 7 degrees of freedom (DOF), which would fit into the existing infrastructure with no or minimal changes on the existing infrastructure

Sensors for product characterization and quality of specialty crops—A review

This review covers developments in non-invasive techniques for quality analysis and inspection of specialty crops, mainly fresh fruits and vegetables, over the past decade up to the year 2010. Presented and discussed in this review are advanced sensing technologies including computer vision, spectroscopy, X-rays, magnetic resonance, mechanical contact, chemical sensing, wireless sensor networks and radiofrequency identification sensors. The current status of different sensing systems is described in the context of commercial application. The review also discusses future research needs and potentials of these sensing technologies. Emphases are placed on those technologies that have been proven effective or have shown great potential for agro-food applications. Despite significant progress in the development of non-invasive techniques for quality assessment of fruits and vegetables, the pace for adoption of these technologies by the specialty crop industry has been slow

Unravelling the bruising discoloration of Agaricus bisporus, the button mushroom

In this research the browning-discoloration caused by bruising of button mushrooms was analysed. Brown-discoloration of mushrooms can amongst others be caused by the picking and storage of mushrooms. Current day commercial hybrids can not be used for mechanical harvesting because mushrooms are sensitive for discoloration. Mechanical harvesting can be used to lower the production costs of mushrooms. To make this possible new hybrids should be available that have a higher tolerance for bruising-discoloration. To breed for new hybrids the cause of bruising-discoloration needs to be analysed. This was done by analysing the compounds (substrates) involved in brown-discoloration and to look at the genes involved. These genes code for the enzymes involved in the conversion of the substrates into the dark brown pigment melanin. The research was performed with commercial and wild strains and the offspring of a segregating population. </p

The Future wave: Redefines contemporary meal preparation and food shopping protocols

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Postharvest Technology

Postharvest management of food crops is an important part of food safety and security across the supply chain. It includes processing of agricultural produce, storage, packaging and coating, postharvest disease management, extending shelf life, and maintaining food quality and safety. Postharvest Technology - Recent Advances, New Perspectives and Applications discusses some important aspects of postharvest technologies. Chapters address such topics as postharvest preservation technology, postharvest disease management, and postharvest processing and packaging

09-07 "Getting Past "Rational Man/Emotional Woman": How Far Have Research Programs in Happiness and Interpersonal Relations Progressed?"

Orthodox neoclassical economics portrays reason as far more important than emotion, autonomy as more characteristic of economic life than social connection, and, more generally, things culturally and cognitively associated with masculinity as more central than things associated with femininity. Research from contemporary neuroscience suggests that such biases are related to certain automatic processes in the brain, and feminist scholarship suggests ways of getting beyond them. The "happiness" and "interpersonal relations" research programs have made substantial progress in overcoming a number these biases. Analysis from a feminist economics perspective suggests, however, several fronts on which research could most profitably continue.

Improving Deaf Accessibility to Web-based Multimedia

Internet technologies have expanded rapidly over the past two decades, making information of all sorts more readily available. Not only are they more cost-effective than traditional media, these new media have contributed to quality and convenience. However, proliferation of video and audio media on the internet creates an inadvertent disadvantage for deaf Internet users. Despite technological and legislative milestones in recent decades in making television and movies more accessible, there has been little progress with online access. A major obstacle to providing captions for internet media is the high cost of captioning and transcribing services. To respond to this problem, a possible solution lies in automatic speech recognition (ASR). This research investigates possible solutions to Web accessibility through utilization of ASR technologies. It surveys previous studies that employ visualization and ASR to determine their effectiveness in the context of deaf accessibility. Since there was no existing literature indicating the area of greatest need, a preliminary study identified an application that would serve as a case study for applying and evaluating speech visualization technology. A total of 20 deaf and hard-of-hearing participants were interviewed via video phone and their responses in American Sign Language were transcribed to English. The most common theme was concern over a lack of accessibility for online news. The second study evaluated different presentation strategies for making online news videos more accessible. A total of 95 participants viewed four different caption styles. Each style was presented on different news stories with control for content level and delivery. In addition to pre-test and post-test questionnaires, both performance and preference measures were conducted. Results from the study offer emphatic support for the hypothesis that captioning the online videos makes the Internet more accessible to the deaf users. Furthermore, the findings lend strong evidence to the idea of utilizing automatic captions to make videos comprehensible to the deaf viewers at a fraction of the cost. The color-coded captions that used highlighting to reflect the accuracy ratings were found neither to be beneficial nor detrimental; however, when asked directly about the benefit of color-coding there was support for the concept. Further development and research will be necessary to find the appropriate solution