The Image Manipulation Technology And Physiological Process Of Southern Blight Of Corn

The image manipulation technology of Southern blight of corn and its principle and monitoring methods are systematic research.Its goal is combined the examination theory and technique of crop disease severity degree with modern information technology, according to present situation,developmental tendency and realistic demand of our country's plant protection work and plant disease monitoring,construct the disease severity degree diagnosis system based on picture recognition of Southern blight of corn, obtaining following conclusion.1 Digital image gathering and pretreatmentIn the experiment,the picture of crops adult plant contains some background factors of the soil,plastic pot,weeds and so on,but the non-plant background red component(R) occupies the dominant position,and the leaf blade partial green component(G)occupies the dominant position,thus,they have provided very good basis for the recognition of plant from the non- plant background.The division to the picture and withdrawing the crops adult plant by using corn adult plant colored picture R,G,B single component and R,G,B combination component,compare the result and discover that the effect of division to corn adult plant by(2G-R-B)is more satisfactory.Regarding massive pictures of crops adult plants' withdrawing,use iteration method to select the best division threshold value. Dividing the pictures with above methods can achieve the automatic division completely, separating the corn adult plant and the background perfectly.2 Relationship between color characteristics value of Southern blight of corn image and single plant disease indexThis experiment is separately established 18 statistical models to forecast single plant disease index of seedling stage and the jointing stage by RGB and HIS colors systematic characteristic value,and separately screens 5 groups with the highest decision coefficient to carry on the confirmation with 15 corn picture color characteristics value. From the decision coefficient of the linearity regression equation,we may see that different model forecast precision is different.As for these two different periods of duration,the forecast precision of regression equations of R,R/G,G/R and disease index is higher.3 Relationship among of the color characteristic value,the ratio of lesion spot area to the whole leaf area and chlorophyll concentration under the single leaf level 3.1 Relationship between color characteristics value and the ratio of lesion spot area to the whole leaf areaFirstly,to choose 6 statistical forecast models with highest decision coefficient from 18 models;Secondly,to confirm the 6 forecast models.The result shows that the forecast precision of the 6 models is high.3.2 Relationship between the ratio of lesion spot area to the whole leaf area and chlorophyll concentrationIt is extremely significant correlation between the ratio of lesion spot area to the whole leaf area and chlorophyll concentration,the correlation coefficient all achieving above 0.95.And with the increasing of percentage of lesion spot,chlorophyll concentration also reduces along with it.3.3 Relationship between color characteristics value and chlorophyll concentration of corn leaf with different disease severity degreeThrough the regression analysis between color characteristic value and chlorophyll concentration of corn leaf with different disease severity degree,confirming the forecast precision of 22 models which are with the high decision coefficient.The result shows that the forecast precision of regression equation of R,G,R/G,G/R,R/(G+B),r,H and chlorophyll a concentration is high and the forecast effect of regression equation of R,G,H and chlorophyll a+b concentration is better,too,but the forecast precision of color characteristic value to chlorophyll b concentration is lower.4 Physiological change of corn adult plant under different disease severity degreeAccording to the classifying standard,the situation of disease severity is divided into 0,0.5,1,2,3 and 4 level,respectively.Then,applying LI6400 portable photosynthesis instrument to measure the plant physiology process.The result indicate that,with the increase of disease severity degree,the net photosyntnetic rate,stomatal conductance and transpiration rate of corn present the droping tendency.