Browsing by Author "Ciampa, Francesco"
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Item Open Access Infrared thermography as a non-invasive scanner for concealed weapon detection(Cranfield University, 2024-02-08T15:55:56Z) Khor, WeeLiam; Chen, Yichen Kelly; Roberts, Michael; Ciampa, FrancescoNon-invasive scanning techniques are vital for threat detection in areas of heavy human traffic to ensure civilian safety. Longer waves in the electromagnetic spectrum, such as millimetre waves and terahertz, have been successfully deployed in commercial personnel scanning systems. However, these waves suffer from lower image resolution due to their longer wavelengths. Infrared has a shorter wavelength compared to millimetre waves and terahertz. Infrared has a lower penetration potential compared to its counterparts but boosts higher image resolution due to its shorter wavelength. Machine learning techniques, i.e., principal component analysis, active contour, and Fuzzy-c, were applied to the infrared images to improve the visualization of concealed objects.Convolutional neural networks, i.e., ResNet-50, were explored as an automatic classifier for the presence of concealed objects. A transfer learning approach was applied to an ImageNet pre-trained ResNet-50 model. After preprocessing the IR images using Fuzzy-c, two models were trained, using 900 and 3082 images, respectively. Evaluating the models using a confusion matrix and receiver operating characteristic curve, an area-under-curve of 0.869 and 0.922 was obtained. An optimization procedure was used to determine the model threshold, resulting in a prediction error of 19.9% and 14.9%, respectively.Item Open Access An optimal steering law for sailing with solar and planetary radiation pressure(Elsevier, 2021-08-25) Barles, Anaïs; Ceriotti, Matteo; Ciampa, Francesco; Felicetti, LeonardAn optimal steering law for sails that exploit both solar and infrared planetary radiation pressure is presented in this paper. The optimal steering law maximises the orbit raise over one revolution of the sail around the planet. An indirect analytical approach, that uses Pontryagin Minimum Principle, is used to develop specialised steering laws for the sunlit and eclipse cases in a planar motion scenario. The law for the sunlit case uses both the solar and infrared radiation emitted from the planet, while the law for the eclipse case finds the optimal sail attitude that maximises the raise of the orbit using only the planetary radiation. Numerical results show that these laws lead to better performance in terms of orbit raising against other sub-optimal and optimal strategies exploiting the solar radiation pressure only. A numerical study is also carried out to show the effects of the reflectivity coefficient in the infrared band on the orbital motion of the sail.Item Open Access Sailing with solar and planetary radiation pressure(Elsevier, 2019-12-05) De Iuliis, Alessia; Ciampa, Francesco; Felicetti, Leonard; Ceriotti, MatteoLiterature on solar sailing has thus far mostly considered solar radiation pressure (SRP) as the only contribution to sail force. However, considering a sail in a planetary mission scenario, a new contribution can be added. Since the planet itself emits radiation, this generates a radial planetary radiation pressure (PRP) that is also exerted on the sail. Hence, this work studies the combined effects of both SRP and PRP on a sail for two case studies, i.e. Earth and Venus. In proximity of the Earth, the effect of PRP can be significant under specific conditions. Around Venus, instead, PRP is by far the dominating contribution. These combined effects have been studied for single- and double-sided reflective coating and including eclipse. Results show potential increase in the net acceleration and a change in the optimal attitude to maximise the acceleration in a given direction. Moreover, an increasing semi-major axis manoeuvre is shown with and without PRP, to quantify the difference on a real-case scenario.Item Open Access Sailing with solar and planetary radiation pressure(Unknown, 2019-08-31) De Iuliis, Alessia; Ciampa, Francesco; Felicetti, Leonard; Ceriotti, MatteoLiterature on solar sailing has thus far mostly considered solar radiation pressure (SRP) as the only contribution to sail force. However, considering a planetary sail, a new contribution can be added. Since the planet itself emits radiation, this generates a radial planetary radiation pressure (PRP) that is also exerted on the sail. Hence, this work studied the combined e ects of both SRP and PRP on a sail for two case studies, i.e. Earth and Venus. In proximity of the Earth, the e ect of PRP can be significant under specific conditions. Around Venus, instead, PRP is by far the dominating contribution. These combined e ects have been studied for single- and double-side reflective coating and including eclipse. Results show potential increase in the net acceleration and a change in the optimal attitude to maximise the acceleration in a given direction. Moreover, an increasing semi-major axis manoeuvre is shown with and without PRP, to quantify the di erence on a real-case scenario.