基于计算机视觉技术评价光照度对斜纹夜蛾幼虫体色的影响

【目的】为揭示光照度对斜纹夜蛾Prodenia litura(Fabricius)幼虫体色变化的影响,建立一套新的昆虫体色评价体系。【方法】采用计算机视觉检测技术,将斜纹夜蛾幼虫的颜色数值化,评价了斜纹夜蛾幼虫体色随日龄的变化规律及光照度对斜纹夜蛾幼虫体色变化的影响。【结果】随着日龄的增加,斜纹夜蛾幼虫的明度(B)和彩色指数(CI)逐渐减少,体色偏差系数(BDV)逐渐增加,色泽从开始的绿色占主导逐渐转变为红色占主导,不同日龄间主观色各颜色指标都差异显著(P<0.01);在低光照度(0~1 000 lx)下,明度(B)和体色偏差系数(BDV)主要受光照影响,而彩色指数(CI)和归一化RGB值主要受发育日龄的影响,在高光照度下(1 000 lx以上),所有颜色指标均受发育日龄影响较大,受光照处理相对较小,光照度对斜纹夜蛾幼虫体色影响的阈值为1 000 lx,在阈值下,明度(B)、彩色指数(CI)及体色分化系数(BDC)都随光照度的增加显著增加,体色偏差系数(BDV)、RGB色差则随光照度的增加而减少。【结论】光照度主要影响斜纹夜蛾幼虫体色的明暗程度,对色彩程度影响不大,且光照度的影响阈值大约为1 000 lx。

Influence of light intensity on the body colour of Prodenia litura （Fabricius） larvae based on computer visualization

Objectives] To reveal the influence of illumination on the body colour of Prodenia litura （Fabricius） larvae, a new system of evaluating insect body colour was established. Method] Based on computer vision detection technology, the change in body colour ofP litura larvae over successive days and the effect of illumination on the change in body colour were evaluated by assigning colours a numerical value. Results] Brightness （B） and colour index （CO decreased gradually of larvae over successive days, while the deviation coefficient （BDV） increased. The dominant colour, green, transformed gradually into red, all color parameters of subjective colour were significantly different among larvae of different ages （P〈0.01）. The brightness （B） and deviation coefficient （BDV） of body colour was influenced by light with low light intensity （0- 1 000 lx）, while colour index （C/） and normalized RGB value were influenced by age. At high light intensity（over 1 000 lx）, all parameters of subjective colour were influenced by age more than light; the effect threshold of light intensity on body-colour was 1 000 lx, at this threshold, the brightness （B）, colour index （C/） and differentiation coefficient of body colour increased with light intensity whereas the deviation coefficient （BDV） and delta-RGB （D） decreased. Conclusion] Light intensity mainly affects thelight and shade of body colour on P lituralarvae but had little effects on the degree of colour; the effect threshold of light intensity was 1 000 lx.