ISSN 1004-4140
    CN 11-3017/P

    工业锥束CT散射修正

    Industrial Cone-beam CT Scatter Correction

    • 摘要: 工业锥束CT是航空航天、电子、汽车等领域无损检测的核心技术,但其成像中的散射伪影会掩盖微小裂纹、虚焊等关键缺陷,严重降低检测精度。当前的大多数散射修正方法仅基于单一的深度学习技术,难以符合实际物理效应而产生HU值偏移。本研究提出两种散射修正。方法:一是投影域的“深度超快玻尔兹曼方程求解器法”,二是图像域的“深度伪影补偿法”。两种方法均以UNet模型替代传统阈值分割,生成高精度物理模板。其中,深度超快玻尔兹曼方程求解器法进一步结合超快玻尔兹曼方程模拟光子物理效应,实现投影域修正,深度伪影补偿法则通过与物理模板的差值运算及低通滤波,完成图像域修正。本研究在铜柱裂隙检测和连接器虚焊检测数据集上对两种方法进行了测试,深度伪影补偿法无需迭代、操作简化,在物理模板标定下相较于图像域仅依靠深度学习的方法RMSE平均提升9.5%,但全局平滑易丢失部分高频信息。深度超快玻尔兹曼方程求解器方法细节保留与修正精度更优,能清晰还原细微结构,在保证结构一致性即SSIM分别为0.96和0.93的同时生成的修正图像与参考图像RMSE仅为11.38HU和32.64HU,相较于其他方法平均提升23.5%。消融实验证实UNet提升模板质量的关键作用。该研究为工业锥束CT提供精度更优的选择,助力无损检测可靠性提升。

       

      Abstract: Industrial cone-beam computed tomography (CBCT) is a core technology for nondestructive testing in fields such as aerospace, electronics, and automotive. However, scattering artifacts in its imaging can obscure critical defects such as microcracks and cold solder joints, thus significantly reducing detection accuracy. Most current scatter-correction methods rely solely on a single deep-learning technique, thus complicating alignment with actual physical effects and causing deviations in the Hounsfield unit (HU) value. This study proposes two scatter-correction methods: the deep ultrafast Boltzmann equation solver method for the projection domain and the deep artifact-compensation method for the image domain. Both methods use the UNet model instead of the conventional threshold segmentation to generate high-precision physical templates. The deep ultrafast Boltzmann equation solver method further combines the ultrafast Boltzmann equation to simulate photon physical effects, thereby achieving correction in the projection domain and completing correction in the image domain via a difference operation involving a physical template and low-pass filtering. This study evaluates both methods on datasets for copper-column crack detection and connector cold-solder joint detection. The deep artifact-compensation method requires no iterations and features simplified operations. Under physical-template calibration, it achieves an average root mean square error (RMSE) improvement of 9.5% compared with image-domain methods that rely solely on deep learning. However, its global smoothing results in the loss of high-frequency information. By contrast, the deep ultrafast Boltzmann equation solver method offers better detail preservation and correction accuracy, thus enabling a clearer restoration of fine structures. While ensuring structural consistency (with structural similarity index values of 0.96 and 0.93, respectively), the RMSE between the corrected images it generates and the reference images is only 11.38 HU and 32.64 HU, respectively, which corresponds to an average improvement of 23.5% over other methods. Ablation experiments confirmed the key role of the UNet model in improving template quality. This study provides an “accuracy–efficiency” option for industrial CBCT, thus contributing to enhanced reliability in nondestructive testing.

       

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