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排序方式: 共有400条查询结果,搜索用时 312 毫秒
161.
162.
基于机器视觉的旱田多目标直线检测方法 总被引:1,自引:5,他引:1
在实际应用中,由于摄像头安装的高度不同或者车辆在地面高低不平的农田内行驶时产生的晃动,都会产生摄像头内出现多作物行的现象。因此根据农田图像的特点,提出了基于已知线的方法判断农作物列数,避免了传统算法只有先确定农作物列数才能提取导航线的弊端。针对农田图像中多列目标检测问题,采用了基于水平线扫描的归类算法,并利用改进的Hough变化快速检测多条定位线。试验结果表明,处理一幅720×480像素彩色图像平均消耗时间为258 ms,98%的图像中所有目标直线都可以检测出来。该算法能够准确提取各种天气环境下农田图像中的列信息,确定多条定位线的方位。 相似文献
163.
黄河中下游湿地土壤铁还原氧化过程的温度敏感性 总被引:1,自引:1,他引:1
土壤中铁的还原氧化过程因与重金属的生物有效性、有机污染的降解及含碳温室气体排放等环境问题关系密切而备受关注。温度可能通过影响铁还原菌或者Fe(II)氧化菌的活性、底物的生物可用性等而影响铁的还原过程。以黄河中下游地区新乡市原阳大米产区的湿地土壤为样品,利用厌氧泥浆控温培养试验方法研究了黄河中下游湿地中土壤铁还原氧化过程的温度敏感性。结果表明:黄河中下游湿地土壤铁的还原容量在16~31℃范围内不受温度影响,但在16~40℃之间升高温度可显著增加铁还原过程的最大速率、速率常数,亦可缩短最大速率出现的时间。铁还原的温度敏感系数介于1.18~3.05之间,且随温度上升而升高。光照可降低铁还原的温度敏感性,平均降幅39.0%。光照时土壤中Fe(II)氧化对温度不敏感。光照条件和铁氧化物的种类和数量可能是影响土壤有机碳矿化的因素之一。研究结果对于深入理解土壤铁的生物地球化学循环及其与土壤呼吸的关系具有重要意义。 相似文献
164.
Dan Yang Jung‐Ah Shin Lu‐Jing Gan Xue‐Mei Zhu Soon‐Taek Hong Chang‐Keun Sung Jin‐Woong Cho Ja‐Hyeong Ku Ki‐Teak Lee 《Cereal Chemistry》2012,89(6):284-289
Until now few comparisons of nutritional compounds in premature green and mature yellow wheat have been reported. In this study, the contents of amino acids, vitamins, mineral compounds, phytosterols, and fatty acids as well as the proximate composition of premature green and mature yellow wheat were investigated. Premature green wheat had lower protein content (12.0 g/100 g db) and higher dietary fiber content (19.3 g/100 g db) than mature yellow wheat (13.6 and 14.3 g/100 g db for protein and dietary fiber, respectively). Despite a small difference in total amino acids, protein in premature wheat had a significantly greater proportion of essential amino acids: 16.1, 39.9, and 32.7 mg/g of protein for methionine, lysine, and threonine, respectively. Furthermore, the protein digestibility‐corrected amino acid scores of whole grain premature green and mature yellow wheat were 62.8 and 46.4, respectively, showing significant difference (P < 0.05). Total fatty acids content was 2.66 g/100 g db for premature green wheat and 2.21 g/100 g db for mature yellow wheat. Vitamin C, β‐carotene (provitamin A), α‐ and γ‐tocopherol, and niacin were the major vitamins in premature green wheat, whereas vitamin C and β‐carotene were not detected in mature yellow wheat. The results obtained indicated that premature green wheat has potential for the human diet because of its desirable nutritional value. 相似文献
165.
基于机器视觉的番茄多目标提取与匹配 总被引:15,自引:10,他引:5
果实的提取和匹配是番茄采摘机器人进行番茄定位和采摘的基础。为解决获取图像中多个成熟番茄粘连或被遮挡的情况下果实的提取和匹配问题,该文提出了使用局部极大值法和随机圆环变换检测圆算法结合进行目标提取,再使用SURF算法进行目标匹配的算法。该方法首先基于颜色对番茄进行分割提取,然后使用局部极大值法对番茄个数进行估计,结合番茄区域面积进行半径估计,之后通过随机圆环变换算法检测番茄中心和半径进行目标定位,再使用SURF算法进行双目目标匹配的算法。该方法在一定程度上解决了复杂自然环境下,多个番茄的提取和图像特征匹配的问题,并通过试验验证了其有效性和准确性,可为采摘机器人目标识别技术的研究提供参考。 相似文献
166.
水稻土中铁氧化还原循环的光照水分效应 总被引:2,自引:1,他引:1
水稻土中铁的氧化还原循环与CO2和CH4排放关系密切。采用恒温厌氧培养试验分别在黑暗、光照条件下研究了不同水分状况对水稻土中铁氧化还原过程、水溶性碳含量及CO2和CH4排放的影响。结果表明,水分和光照是调控土壤铁氧化还原过程及其耦合的碳转化过程的关键环境因子。避光时增加含水量缩短铁还原最大速率出现的时间,促进CH4排放。光照条件下含水量小于50%时增加含水量可促进亚铁的再氧化,大于50%时则抑制了亚铁的再氧化。避光时增加含水量可增加体系的水溶性无机碳含量(WSIC),WSIC与CH4的排放存在显著正相关关系。光照可显著降低体系的WSIC,降低幅度随含水量的增加而增大。在含水量25%~200%范围内,光照可使CO2和CH4排放量分别降低95.80%和96.08%。 相似文献
167.
I. Alić T. Trbojević Vukičević M. Đuras S. Kužir G. Fazarinc V. Gjurčević Kantura 《Anatomia, histologia, embryologia》2014,43(1):16-21
Muscle variations take the form of additional muscle bundle or belly, unusual muscle origin or termination, as well as complete muscle absence. Knowledge of such variations not only has clinical importance for guiding surgery, but also can help reveal phylogenetic relationships. To improve our understanding of muscle variations in dogs, 57 medium‐sized, cross‐breed male and female adult animals were dissected as part of a gross anatomy course between 2005 and 2011. Variations in pectoral girdle muscles were observed in 7 (12.3%) dogs and took the form of an additional muscle bundle in the brachiocephalicus muscle (n = 2), in the omotransversarius muscle (n = 2), in the cervical part of the rhomboideus muscle (n = 2) and in the cervical part of the serratus ventralis muscle (n = 1). Muscle variation was bilateral in only one dog; it involved the omotransversarius muscle. The variations did not seem to be sex dependent. Such variations can appear regularly in dogs and should be taken into consideration during anatomical dissection. 相似文献
168.
A hypolipemic effect of the water extract of Picrorrhiza kurroa (PR) was observed in a high fat diet feeding hyperlipemic mouse at doses of 50, 100 and 200 mg/kg, orally, once a day for 12 weeks. Liver weight, serum aspartate transferase (AST), alanine transferase (ALT), low density lipoprotein (LDL), triglyceride and total cholesterol levels were significantly reduced by the treatment. On the contrary, serum HDL level seems not affected by P. kurroa water extract. 相似文献
169.
The distributions and frequencies of some endocrine cells in the eight portions of the gastrointestinal (GI) tract - fundus, pylorus, duodenum, jejunum, ileum, cecum, colon and rectum of the nude mouse, Balb/c-nu/nu were studied with immunohistochemical method using six types of anti-sera against serotonin, gastrin, cholecystokinin (CCK)-8, somatostatin, glucagon and human pancreatic polypeptide (hPP). All of six types of immunoreactive (IR) cells were identified. Most of IR cells in the intestinal portion were generally spherical or spindle in shape (open type cell) while cells showing round in shape (close type cell) were found in the intestinal gland and stomach regions occasionally. Their relative frequencies were varied according to each portion of GI tract. Serotonin-IR cells were detected throughout the whole GI tract and they showed the highest frequency in the pylorus. Gastrin-IR cells were restricted to the pylorus and duodenum with numerous and a few frequencies, respectively. CCK-8-IR cells were also restricted to the pylorus, duodenum and jejunum with numerous, a few and rare frequencies, respectively. Somatostatin-IR cells were demonstrated throughout the whole GI tract except for the colon and rectum, and they showed the highest frequency in the fundus. In addition, glucagon- and hPP-IR cells were restricted to the fundus and rectum, respectively with a few frequencies. In conclusion, the general distribution patterns and relative frequency of GI endocrine cells of the nude mouse, Balb/c-nu/nu was similar to that of other strains of mice. However, some strain and/or species-dependent unique distributions and frequencies of endocrine cells were also observed especially for somatostatin- and hPP-IR cells. 相似文献
170.
In our previous research, the possibility of using chitosan in preparing the pretreatment print paste for digital ink-jet
printing for cotton fabric was investigated but the final color was not good as expected. In this paper, we modified our previous
work by applying the chitsoan separately on the cotton fabric for digital ink-jet printing. A two-bath method was thus proposed
and it was confirmed that a better color yield was achieved with this method. However, the use of chitosan reduced the tensile
strength of the digital ink-jet printed fabric slightly. 相似文献