Effects Of Dust Footprint On Smooth Ceramic Tiles And Composite Floorboard By Panchromatic Footprint Reconnaissance

Dust footprint is one of the most common marks left behind at crime scene.Comparing to other vestige evidence,footprint is difficult to conceal.Therefore,dust footprint is significantly important to combining cases,analyzing case characteristics,determining routes of entrance and egress,the number of criminals and criminal sketch.The photograph of material evidence at crime scene is always a key focus of the nondestructive examination research in China and other countries.For the dust footprint on the smoothly colored object surface,the method of combining grazing incidence illumination technique and color separation photograph technique is commonly used,in order to increase the contrast by using the complementary chromatic light to the color of the object as illuminating light.The illuminating source of panchromatic footprint reconnaissance can be promptly adjusted by changing the light in different ranges of wavelength to meet the requirements for collecting the dust footprint in different colors carriers on the scene.The illuminating source of panchromatic footprint reconnaissance has several advantages over the traditional color separation photographic equipment,such as more portable,more convenient and fast to change light wavelength,easier to remove facula,etc..Based on the advantages stated above,the illuminating source of panchromatic footprint reconnaissance is exceptionally suitable as the color separation photographic equipment for collecting dust footprint on the scene.In this study,the newest illuminating source for panchromatic footprint reconnaissance was used to analyze the effects of dust footprint appearance on smooth tile and floorboard in different colors,including smooth-glossy ceramic tiles,smooth-matte ceramic tiles,smoothcomposite floorboard.In the experimental process,the influencing factors included color,irradiating distance,reflections on surface material,exposure compensation,etc..The purpose of this research was to study the influence of panchromatic footprint reconnaissance illuminating source on potential appearance of dust footprint on smooth tile and floorboard.This article summarized the advantages and disadvantages of panchromatic footprint reconnaissance by illuminating source,presented the principle and suggestion to improve the equipment,and provided theoretical guidance for investigating and solving cases to police officers.The conclusions indicate that: 1.The requirements for collecting and analyzing of dust footprint are satisfied by using panchromatic footprint reconnaissance illuminating source on the smooth ceramic tiles and composite floorboards in a variety of colors.2.The imaging efficacy of dust footprint is influenced by the factors of color,irradiating distance,reflections on surface material,exposure compensation,etc..3.The illuminating source for panchromatic footprint reconnaissance is recommended to use in basic level investigation at crime scene.