摘要
继“数字图像处理法确定林带疏透度随机误差研究”之后,研究了数字图像处理法确定林带疏透度的投影误差和影缩误差。文中阐述了在林带像片上离像主点越近投影误差绝对值越小而影缩误差与在像片上的位置无关的规律;揭示了像片疏透度中的投影误差绝对值与照像机焦距和摄影距离均呈负相关的原理;分别建立了矩形、品字形和斜线等3种主要配置类型林带干部像片疏透度中投影误差和影缩误差模型;综合对诸误差研究的结论,提出了从测定样本量的确定和野外摄影到室内测定直至误差计算的尽量缩小、限制诸误差,订正林带干部像片疏透度中投影误差和影缩误差,最终实现按已知或既定界限值的准确度确定林带疏透度的一整套技术措施。
Both projective and contractive aberrations of shelterbelt porosity estimated by measuring photograph with the help of digitized photographic silhouettes are further studied on the basis of 'Study on random error of shelterbelt porosity estimated by measuring photograph with the help of digitized photographic silhouettes'. The regular patterns of 'the closer the image of shelterbelt is to main point on a photograph, the less absolute value of projective aberration in the porosity is', and 'contractive aberration in the porosity is irrelevant to the location of shelterbelt on a photograph' are expounded,and the fact that absolute value of projective aberration in the porosity is negatively related to both focal length of camera and distance of taking a picture is clarified. Of projective and contractive aberrations in the porosity under crown of the shelterbelt disposed respectively by 3 main patterns of rectangle, triangle and oblique line, the models are established. Based on synthesizing the results of study on the errors in the porosity, a series of measures from calculating the number of observation and taking a picture in field to measuring photograph in laboratory up to calculating the errors are advanced to shrink and restrict all errors in the porosity as far as possible,to emend both projective and contractive aberrations in the porosity under crown of shelterbelt, and to estimate the porosity according to known or given error limit.
出处
《应用生态学报》
CAS
CSCD
1992年第2期111-119,共9页
Chinese Journal of Applied Ecology
基金
国家自然科学基金
关键词
疏透度
投影误差
影缩误差
Porosity, Farmland shelterbelt, Projective aberration, Contractive aberration, Digitized photographic silhouettes.
