| Loadbearing is a kind of behavior characteristic that often appears when a criminal suspect comes in and out of the scene of a case,and it is often associated with the footprint of the scene of a case.Of suspects in the purpose of this paper is to the scene of the crime of his arms,double shoulder,the single shoulder,the portable way of four kinds of load under different load weight and reflected the footprint of stride,plantar pressure characteristics research,comprehensive and systematic quantitative inspection of footprint inspection theory under the condition of new technology background,especially under the condition of load footprint inspection theory must be added.In this paper,the influence of loading form and loading weight on the footprint characteristics was explored by comparing the changes of footstep characteristics and planthar pressure characteristics of normal walking,two hands holding,two shoulders carrying,one shoulder carrying and one hand carrying with the changes of footstep characteristics and planthar pressure characteristics under the two loading weights of 5kg and 10 kg respectively.For image processing,Photoshop software was used to segment and integrate the collected footprint samples,Python was used to extract the data,and IBM SPSS Statistics 24 statistical software was used to determine whether the data obeyed the normal distribution and the paired sample t test was used to analyze the data.Finally,linear discriminant analysis was made for the footprint data under different loading methods and loading weights.The experimental results showed that :(1)There were some common changes among different loading modes.The variation of stride characteristics of male and female was similar,and the step length decreased.When the load of 5kg was compared with that of 10 kg,the difference between the characteristic data of foot pressure and stride length was small.After loading,the contact area between the plantar and the ground increased,while the contact area of the toe area changed little.The change of the plantar area and heel area was mainly due to the increase of the value of high color order,and the contact area of the arch area and heel area increased.(2)The variation of stride characteristics was consistent with that in traditional studies.The contact area data of the arch area and the heel area showed significant differences,which could be used as a set of parameters to distinguish the differences between samples.The pressure surface of the foot area shifted laterally with the increase of the loading weight.(3)Double shoulder and back type load,step length becomes smaller,step width becomes larger,step Angle slightly increases.The pressure surface of the foot area tends to spread from the inside to the outside edge and increases with the increase of the weight.(4)Single-shouldered load.Take the right load as an example,the left step is longer than the right step,the step width changes little,the right step Angle decreases,and the left step Angle increases gradually.The pressure value of the left foot is greater than that of the right foot,and the pressure surface of the left plantar area shifts outward,and the medial pressure of the right plantar area increases.(5)For single-hand loading,the length of the left step is larger than that of the right step,and the step Angle and width are both smaller;The pressure value of the left foot was generally higher than that of the right foot,the medial pressure of the right metatarsal region increased,and the pressure of the left metatarsal region shifted outwards.(6)In the pre-experiment,linear discriminant analysis was conducted on the footprint characteristic data of the four loading methods,and the accuracy of the results was about 70%.On this basis,linear discriminant analysis was conducted for different loading weights under a single loading mode,and the results could distinguish 100% of the three types of footprint characteristic data,namely,no loading,5kg loading and 10 kg loading. |
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