面向眼轴测量系统的瞳孔中心定位算法

Pupil center location algorithm for axial length measurement system

  • 摘要: 为提升基于低相干干涉原理的眼轴测量系统在图像采集阶段的自动化与定位精度,提出一种面向瞳孔中心识别的轻量化图像分割模型。该模型融合基于Mamba状态空间建模启发的注意力机制,用于增强对小目标区域的特征表达;引入频域融合与双残差连接,提升跳跃连接中的边缘定位能力;同时采用深度可分离卷积以降低模型复杂度,提升嵌入式部署性能。采用海康相机采集图像构建数据集进行实验验证,结果表明模型在mIoU(mean intersection over union)指标上较SE(squeeze-and-excitation)模块提升0.89%,较CBAM(convolutional block attention module)提升1.05%;在Recall指标上较TransUNet提升0.49%;整体识别准确率达99.86%,在强光干扰与睫毛遮挡等复杂环境下仍具良好稳定性。进一步结合 Canny 边缘检测与最小二乘椭圆拟合算法,实现瞳孔中心的高精度定位。该方法为眼轴测量系统提供了鲁棒、精确的图像处理方案,显著提升系统自动化与光路对准能力。

     

    Abstract: To enhance the automation and positioning accuracy of the ocular axis measurement system based on low-coherence interferometry principle during the image acquisition stage, a lightweight image segmentation model for pupil center recognition was proposed. This model integrated an attention mechanism inspired by the Mamba state space modeling to enhance the feature representation of small target regions. It introduced frequency domain fusion and dual residual connections to improve the edge localization ability in skip connections; and it employed depthwise separable convolution to reduce model complexity and improve the performance of embedded deployment. Experiments were conducted using images collected by a Hikvision camera to build a dataset. The results show that the model achieves a 0.89% improvement in mIoU(mean intersection over union) compared to the SE(squeeze-and-excitation) module and a 1.05% improvement compared to CBAM(convolutional block attention module).It also improves the Recall index by 0.49% compared to TransUNet. The overall recognition accuracy reaches 99.86%, maintaining good stability in complex environments such as strong light interference and eyelash occlusion. Further, by combining Canny edge detection and least squares ellipse fitting algorithm, high-precision pupil center localization is achieved. This method provides a robust and accurate image processing solution for the ocular axis measurement system, significantly enhancing its automation and optical alignment capabilities.

     

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