纸质档案数字化成果原始分辨率篡改的检测方法

纸质档案数字化成果的原始分辨率是光学字符识别（OCR）精度的重要影响因素,为保证档案图像的原始分辨率大于等于300dpi,在档案预检阶段需检测出较低原始分辨率被篡改为较高分辨率的档案图像。针对图像文件头篡改、图像内容插值等多种分辨率篡改手段,分析它们的篡改机理,设计了由文件头检测、图像频率域分析、图像质量客观评价多方案组成的综合的篡改检测策略。在宁波市档案局的测试数据库上显示,所提出的原始分辨率篡改检测方法取得了很好的效果。

Detection of Original Resolution Tampering in Digital Result of Paper Records

The original resolution of the digital result of paper records has a significant influence on the accuracy of optical character recognition (OCR). In order to ensure that the original resolution of archives image is greater than or equal to 300 dpi, it is necessary to detect original low resolution of archives images which were tampered to high resolution in the pre-inspection stage. Several resolution tampering methods, like file header tampering and image interpolation, are investigated by analyzing their tampering mechanism, and the comprehensive tampering detection strategy is worked out composed by file head detection, image frequency domain analysis and objective image quality assessment. The proposed detection method of original resolution tampering has achieved good results in the test database of Ningbo Archives.