为了减少屈光度测量误差，提高精度。本文针对哈特曼法焦度测量建立了较详细的误差模型，着重分析了光源的色散误差、入射光与透镜未垂直、光电探测器中心定位不准、透镜倾斜、光源光线主轴与透镜主轴未重合所引起的屈光度测量误差。结果表明，得出由于光电探测器上中心提取的不准确，会对最终的结果产生较大的误差。并由此提出了双重双线性插值结合拟合法来求取中心的方法，并证明了其有效性和准确性。

In order to reduce the error and improve the measurement accuracy, a more detailed error model is established for the Hartmann method of focal power measurement in this paper. It focuses on the analysis of several problems that cause the error of refraction problems, including the dispersion error of the light source, the inaccurate of the photodetector’s central positing, the tilt of lens, misalignment between incidence axis and main axis of lens, and the incident light and the lens are not perpendicular. At last, it is concluded that the inaccuracy of the center extraction on the photodetector will cause a large error to the final result. For all these reasons, a method of dual bilinear interpolation combined with a fitting method to find the centroid is proposed, proving its effectiveness and accuracy.