A Two-Dimensional Adaptive Target Detection Algorithm in the Compressive Domain.

By applying compressive sensing to infrared imaging systems, the sampling and transmitting time can be remarkably reduced. Therefore, in order to meet the real-time requirements of infrared small target detection tasks in the remote sensing field, many approaches based on compressive sensing have been proposed. However, these approaches need to reconstruct the image from the compressive domain before detecting targets, which is inefficient due to the complex recovery algorithms. To overcome this drawback, in this paper, we propose a two-dimensional adaptive threshold algorithm based on compressive sensing for infrared small target detection. Instead of processing the reconstructed image, our algorithm focuses on directly detecting the target in the compressive domain, which reduces both the time and memory requirements for image recovery. First, we directly subtract the spatial background image in the compressive domain of the original image sampled by the two-dimensional measurement model. Then, we use the properties of the Gram matrix to decode the subtracted image for further processing. Finally, we detect the targets by employing the advanced adaptive threshold method to the decoded image. Experiments show that our algorithm can achieve an average 100% detection rate, with a false alarm rate lower than 0.4%, and the computational time is within 0.3 s, on average.

Clinical characteristics of poly-drug abuse among heroin dependents and association with other psychopathology in compulsory isolation treatment settings in China.

OBJECTIVE: To investigate clinical characteristics and associations of polydrug abuse among heroin-dependent patients in compulsory isolation settings in China. METHODS: Structured interviews were conducted in 882 heroin-dependent patients in two compulsory isolation settings in Changsha, China. Descriptive statistics were employed to report prevalence and general information of polydrug abuse among the participants. Bivariate associations were examined between polydrug abuse and variables regarding demographics, heroin use profile and psychopathology. Multivariate logistic regressions were conducted to determine independent factors associated with polydrug abuse. RESULTS: Of all the participants, 40.6% reported abuse of/dependence on at least one other type of drug/alcohol than heroin/opioids during the month preceding admission, with benzodiazepines and alcohol being the most common type of drugs abused apart from heroin. Antisocial and depressive personality disorders, as well as more severe heroin use patterns, including younger age at initiate use and larger amount used per day, were found to be independently associated with polydrug abuse. CONCLUSIONS: The prevalence of polydrug abuse and its associated severe heroin use patterns and personality disorders suggests an urgent need of promoting treatment policies and strategies for heroin patients in China to address these issues.