基于红外反射摄影技术显现烧毁文件上的字迹

Appearance of Writings on Burned Documents Based on Infrared Reflection Photography

摘要: [目的]利用红外反射摄影技术显现烧毁文件上的字迹，归纳分析不同波段的红外光对不同类型字迹的显现结果，为烧毁文件的检验工作提供参考数据。[方法]选取黑、红、蓝三种颜色的中性笔、圆珠笔、油性笔、中油笔，共12种类型的笔，以及白色A4复印纸，制作了12份含有书写字迹的烧毁文件实验样本。利用785 nm、805 nm、850 nm、980 nm四个波段的红外光，对烧毁文件上的字迹样本进行检验，比对不同波段的红外光对烧毁文件上字迹的显现结果，分析影响字迹显现效果的因素。[结果]在可见光下难以辨识的黑色字迹，利用红外反射摄影，字迹辨识度显著提高；对于红色字迹和蓝色字迹，在可见光下难以辨识，利用红外反射摄影依旧不能得到理想的显现效果。基于红外反射摄影技术的相关原理，能够显现烧毁文件上的字迹。[结论]红外反射摄影技术可以无损显现烧毁文件上的字迹，为基层公安工作中烧毁文件物证的检验鉴定提供了一个简单有效的解决方法。

Abstract: [Purpose] To use infrared reflection photography to reveal the text on burned documents, and to analyze the visibility of different types of text under various infrared wavelengths, providing reference data for the examination of burned documents. [Method] Twelve types of pens—black, red, blue, ballpoint, oil-based, and medium oil-based, and white A4 copy paper were selected to create 12 experimental samples containing written text on burned documents. Infrared light at 785 nm, 805 nm, 850 nm, and 980 nm was used to examine the text samples on the burned documents, comparing the visibility effects of different wavelengths and analyzing the factors affecting the visibility of the text. [Result] Black text, which is difficult to read in visible light, showed a significant improvement in readability using infrared reflection photography; however, red and blue text, which are also difficult to read in visible light, did not achieve satisfactory results with infrared reflection photography. Based on the principles of infrared reflection photography, the text on burned documents can be clearly revealed. [Conclusion] Infrared reflection photography can non-destructively reveal the text on burned documents, providing a simple and effective solution for the examination and identification of burned document evidence in grassroots public security work.