RESUMO
Shadow removal is an important issue in the field of motion object surveillance and automatic control. Although many works are concentrated on this issue, the diverse and similar motion patterns between shadows and objects still severely affect the removal performance. Constrained by the computational efficiency in real-time monitoring, the pixel feature based methods are still the main shadow removal methods in practice. Following this idea, this paper proposes a novel and simple shadow removal method based on a differential correction calculation between the pixel values of Red, Green and Blue channels. Specifically, considering the fact that shadows are formed because of the occlusion of light by objects, all the reflected light will be attenuated. Hence there will be a similar weakening trends in all Red, Green and Blue channels of the shadow areas, but not in the object areas. These trends can be caught by differential correction calculation and distinguish the shadow areas from object areas. Based on this feature, our shadow removal method is designed. Experiment results verify that, compared with other state-of-the-art shadow removal methods, our method improves the average of object and shadow detection accuracies by at least 10% in most of the cases.
RESUMO
OBJECTIVE: To discuss the distribution of the respiratory complications in severely burned patients and the prevention and treatment experience against them. METHODS: Medical records of 922 adult patients with severe or extremely severe burn hospitalized in our burn ICU from January 2005 to December 2012 were screened and retrospectively analyzed, including patients transferred from other hospitals, patients with total burn area above 50% TBSA, the distribution and treatment of respiratory complications, and the mortality. Data were processed with chi-square test. RESULTS: The constituent ratio of patients transferred to our hospital was 71.1% in 2007 and 40.2% in 2010, while it remained about 50.0% in the other years. The ratios of patients with total burn area larger than 50% TBSA and that of patients with respiratory complications (χ(2) = 2.637, P > 0.05) showed no significant changes each year. Among these 922 burn patients, 523 patients suffered respiratory complications, among which laryngeal edema (50.9%, 266 cases), pulmonary infection (21.6%, 113 cases), and ARDS (11.9%, 62 cases) were the main components, with no significant change each year (with χ(2) values respectively 6.132, 6.319, 0.016, P values above 0.05). Among the patients with respiratory complications, except for 36 were not treated actively, 487 were treated by ventilator among which 228 had undergone tracheostomy, and the constituent ratios in the 8 years were close. Fifteen patients died, with 2 died of laryngeal edema, 3 of ARDS, and 10 of sepsis or MODS as a result of sepsis. CONCLUSIONS: Patients with severe burns were at high risk of respiratory complications, among which laryngeal edema was common, followed by pulmonary infection and ARDS. Prophylactic tracheostomy, mechanical ventilation, wound therapy, and anti-infection were all effective measures of prevention and treatment against these complications.
