为克服传统光干涉式甲烷测定器存在肉眼辨别零级条纹所在目镜标尺位置容易产生人为 误差的缺点，明确温度和非甲烷气体因素对光干涉式甲烷测定器性能的影响，选择电荷耦合元 件(CCD)替代原目镜标尺结构，在 CCD 获取干涉条纹灰度信息的基础上，采用峰值提取结合高斯 拟合来精确定位零级条纹，线性拟合 CH4 体积分数 1%，4%，7%，10%时的零级条纹位移值与体积 分数的关系式，并选取了 0.494%，0.994%，1.490%和 3.940%这 4 种 CH4 标气进行测量精度和测量 稳定性试验;设置了温度漂移试验，根据零点温度漂移曲线进行二次项温度补偿;理论推导了 CO2 等煤矿井下常见的非甲烷气体的测定器测量值，并进行了标准气体测试试验。 研究结果表明:拟合 得到的体积分数计算关系式决定系数 R2 为 0.998 7，线性度与理论公式基本一致，可利用未知 CH4 体积分数引起的位移值来自动计算出体积分数，且试验结果证明改进后的光干涉式甲烷测定器的 测量精度高、测量稳定性好，优于技术标准要求;经过二次项温度补偿后零值受温度影响小，零值漂 移范围基本集中于±0.05%;检测气样中 CO2 每增加 1%会导致测定器 CH4 测量值增加 1.033%，空气 中每减少1%的O2会导致测定器CH4测量值增加0.18%。 改进后的光干涉式甲烷测定器与传统测 定器相比，实现了零级条纹的自动定位与数字化处理，克服了人为误差大的缺点，提高了测量精度， 并减小温度漂移造成的测量误差。

In order to overcome the shortcoming that the eyepiece ruler position of the zero⁃order fringe distinguished by the naked eye is easy to cause errors，and study the influence of temperature and non⁃methane gas factors on the performance of the traditional optical interference methane detector. The photoelectric conversion device CCD is cho⁃ sen to replace the original eyepiece ruler structure. The peak extraction combined with Gaussian fitting is used to accurately locate zero⁃order fringes on the basis of the gray information of interference fringe obtained by CCD. Also，the re⁃ lationship between the zero⁃order fringe displacement and the methane concentration is linearly fitted when the meth⁃ ane concentration is 1%，4%，7% and 10%. Methane calibration gases of 0. 494%，0. 994%，1. 49% and 3. 94% are selected for the measurement accuracy and measurement stability experiments. The temperature drift experiment is set up，and the quadratic term temperature compensation is carried out according to the zero⁃drift curve. The measurement value of the common coal mine non⁃methane gas such as carbon dioxide is theoretically deduced， and the standard gas test experiment is carried out. The research results show that the coefficient of determination R2 of the concentration calculation relationship obtained by the fitting is 0. 998 7，and the linearity is basically consistent with the theoretical formula. The displacement caused by the unknown methane concentration can be used to automati⁃ cally calculate the methane concentration value. The experimental results prove that the improved optical interfer⁃ ence methane detector has high measurement accuracy and good measurement stability，which is better than the coal industry standard requirements. After the quadratic term temperature compensation，the zero value is less affected by temperature， and the drift value is basically concentrated at ± 0. 05%. Each increase of 1% carbon dioxide in the test gas will increase the measurement value of methane by 1.033%，and each decrease of 1% oxygen in the standard air will increase the measurement value of methane by 0.18%. Compared with the traditional detector，the im⁃ proved optical interference methane detector realizes the automatic positioning and digital processing of the zero⁃order fringe， overcomes the shortcomings of large subjective influence， improves the measurement accuracy， and reduces the measurement error caused by temperature drift.