Browsing by Author "Oliveira, Josenalde"
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- Comparative analysis between LDR and HDR images for automatic fruit recognition and countingPublication . Pinho, Tatiana M.; Coelho, João Paulo; Oliveira, Josenalde; Boaventura-Cunha, JoséPrecision agriculture is gaining an increasing interest in the current farming paradigm. This new production concept relies on the use of information technology (IT) to provide a control and supervising structure that can lead to better management policies. In this framework, imaging techniques that provide visual information over the farming area play an important role in production status monitoring. As such, accurate representation of the gathered production images is amajor concern, especially if those images are used in detection and classification tasks.Real scenes, observed in natural environment, present high dynamic ranges that cannot be represented by the common LDR (Low Dynamic Range) devices. However, this issue can be handled by High Dynamic Range (HDR) images since they have the ability to store luminance information similarly to the human visual system. In order to prove their advantage in image processing, a comparative analysis between LDR and HDR images, for fruits detection and counting, was carried out.The obtained results show that the use of HDR images improves the detection performance to more than 30% when compared to LDR.
- A new brain emotional learning simulink toolbox for control systems designPublication . Coelho, João Paulo; Pinho, Tatiana M.; Boaventura-Cunha, José; Oliveira, JosenaldeThe brain emotional learning (BEL) control paradigm has been gathering increased interest by the control systems design community. However, the lack of a consistent mathemat- ical formulation and computer based tools are factors that have prevented its more widespread use. In this article both features are tackled by providing a coherent mathematical framework for both the continuous and discrete-time formulations and by presenting a Simulink R computational tool that can be easily used for fast prototyping BEL based control systems.
- Optimized fractional order sliding mode controller for water level in irrigation canal poolPublication . Oliveira, Josenalde; Pinho, Tatiana M.; Coelho, João Paulo; Boaventura-Cunha, JoséWater level regulation of irrigation canals represents a major challenge for control systems design. Those systems exhibit large dynamic variations in their operating conditions. To overcome this fact, robust controllers should be applied. The sliding mode control paradigm reveals this ability which make it a suitable candidate to be incorporated in the irrigation canal control loop. Moreover, its exibility can be further potentiated by extending the ordinary formulation by adding fractional-order integro-di erential operations. In this work, fractionalorder sliding mode control is applied to the above mentioned problem. This application represents a novelty and, according to the obtained simulation results, leads to an accurate and proper performance when compared to its integer-order counterpart and to a fractional proportional-integrative controller, recently proposed for this problem.