Search

The diversity of informal settlement morphologies across locales makes their mapping inherently challenging in heterogeneous urban landscapes. The aim of this study was to evaluate the potential of pansharpening techniques on Sentinel 2A data, and textural features, in enhancing informal settlement identification accuracy in a fragmented urban environment. Brovey transform, intensity, hue and saturation transform, Environmental Systems Research Institute (ESRI), simple mean, and Gram–Schmidt techniques were employed to pansharpen multispectral bands of Sentinel 2A, bands 5, 6, and 7 in the first group, and bands 8A, 11 and 12 in another, using an average of bands 4 and 8 as the panchromatic band. The main objective was to investigate the efficacy of pansharpening Sentinel 2A imagery and texture analysis in automated mapping of morphologically varied informal settlements. An evaluation of the quality of fused images was undertaken through computation of the correlation between the spectral values of the original multispectral and pansharpened image. Grey-level-co-occurrence matrix texture features were extracted from the pansharpened images, and subsequently incorporated in the classification process, using a support vector machine classifier. Our results confirm that the Gram–Schmidt fusion technique yielded the highest informal settlement identification accuracy (F-score 95.2%; overall accuracy 91.8%). The experimental results demonstrated the potential of pansharpening Sentinel 2A, and the added value of image texture for a more nuanced characterisation of informal settlements. [ABSTRACT FROM AUTHOR]

Finding patches is a crucial step in a pavement performance survey. The study develops a machine learning and image processing algorithm-established automatic method for identifying asphalt pavement patches. The GrayLevel Co-Occurrence Matrix and image texture-based features derived from color channel statistics are used as input parameters to describe the condition of the pavement. For feature extraction, image processing methods like the projective integral of images, steerable filters, and an improved image thresholding method were used. Support Vector Machine is employed for categorizing the differentiating patched regions from non-patch ones. The suggested combination of image texture analytical methods has been trained using an IA data set created from 400 image samples. The feature set, which combines the characteristics of cracked objects with those generated from the projective integral, can produce the desired result. To make the model's execution simpler, a patch recognition program was created and implemented in MATLAB. As a result, the recently created method has the potential to be an instrument for traffic management organizations through the assessment of pavement performance. The results of the experiments indicate that the newly developed method may achieve excellent accuracy prediction results with a classifier performance rate of about 96%. Such a method could enable transportation authorities to assess the state of asphalt pavement. [ABSTRACT FROM AUTHOR]

A recirculating aquaculture system (RAS) has widely been acknowledged as eco-friendly land-based aquaculture since only a limited amount of water is used in recirculation. There is also much greater potential in modern intensive aquaculture, compared with conventional fish production. A key feature of RAS is the high precise controlling of the water environment in the rearing tank and the feeding of rearing fish. Water environmental parameters (such as water temperature, and oxygen levels) can provide stable and optimal conditions for less stress and better growth during fish living. In addition, fish feeding plays a vital role in RAS, because starvation may impact the organizational structures of fish, whereas, overfeeding may threaten the survival of animals, as well as the water quality. Therefore, it is essential to investigate the strategy of fish feeding in RAS. Currently, the feeding events are mainly implemented by the feeding machine with predetermined and fixed feeding times and quantities, according to the experience rather than the real fish appetite. Thus, it is necessary to evaluate the fish behavior pattern and appetite in the feeding strategy for a higher performance of RAS. In this study, an innovative evaluation of fish feeding behavior was proposed using Fourier spectrum feature extraction and support vector machines (SVM) classification. The degree of surface ripple dispersion was considered to predict the fish feeding behavior, rather than the only movement of fish bodies in conventional cases. Firstly, a high-speed video camera was used to capture the process before and after feeding. The video images were then converted from RGB to HSV space, where the background including the water ripple was subtracted, and the contrast was enhanced via the thresholds of saturation and brightness. Secondly, fast Fourier transform (FFT) was adopted to transform the image information from the spatial to a frequency domain. The fluctuation level of ripples in the image was regarded as an indicator of fish appetite using the amplitudes in the frequency spectrum. Specifically, the frequency spectrum was characterized by a high frequency, short period, and a large sum of amplitudes, when the fishes presented high appetite, and vice versa. Thirdly, the database of feature vectors was generated using the self-developed loop filters with various diameters. Finally, the obtained feature vector was trained to SVM. The feature vector of the SVM model was then optimized, where the optimal kernel width and penalty coefficient were selected to efficiently judge the feeding desire of fish during the cross validation. Moreover, a comparison was conducted to verify the efficiency, among the proposed, optical flow, image texture, shape, and texture features. As such, the original interference condition was transformed into the judgment, indicating the better universality of RAS against the high fish density, unstable water surface ripple, and dark light in the system. A field test also demonstrated that a high accuracy of 99.24% was achieved in judging the feeding behavior of farmed fish in RAS. In practice, it is strongly recommended to take videos of farmed fish as the training data for the classifier of fish feeding behavior. Consequently, the improved RAS can also be incorporated into the feeding machine to supervise the real-time smart and precise feeding events in modern aquaculture. [ABSTRACT FROM AUTHOR]

Texture classification has been one of the problem-solving strategies. The feature selection technique is critical for increasing the efficiency of machine learning because it significantly improves the performance of texture classification by removing irrelevant features from the original collection. The majority of methods for selecting features are statistical in nature. Accuracy in database classification is primarily achieved by selecting attributes and simultaneously increasing the classification rate. The task's primary objective is to select the most significant features from the feature database for execution. We use the cluster-based feature selection method to derive features for statistical and structural approaches. The proposed strategy should be implemented in three stages. To begin, the function can be extracted using the local binary pattern (LBP), the gray level co-occurrence matrix, or the Gabor filter. Following that, a modified K-means clustering method is used to select features using four standard distance measurements: Euclidean, Minkowski, Chebychev, and City Block. Finally, benchmark classifiers such as naive bayes (NB), support vector machine (SVM), and K-nearest neighbor (KNN) were used to effectively compute the classification accuracy of the research. The proposed approach achieves accuracy of 99.4328 for KNN, 98.6654 for NB, and 99.6712 for SVM with the highest classification rate. [ABSTRACT FROM AUTHOR]