人眼角膜曲率参数亚像素测量系统的设计

Design of Subpixel Algorithm of Dioptric Paramater Measurement System for Eye Cornea

为了提高人眼角膜曲率参数的测量精度,设计了一套角膜测量系统.利用红外光将标准的靶环投影到人眼角膜上,反射后形成带有眼角膜参数特性的虚物,该物再经光学系统成像在CCD图像传感器上.然后通过高速DSP TMS320F2812进行图像二值化处理,最后采用插值方法计算角膜曲率参数.实验用标准角膜模拟眼进行了测试,结果同日本TPCON KR-8100角膜/验光仪比对,结果表明:计算结果达到亚像素精度,二者测量误差小于国家计量规定的检查最小误差±0.02 mm.

Measurement system of cornea were designed to improve diopter parameter measurement precision of eye cornea. Standard ring was projected onto an eye cornea with infrared, after reflecting from eye cornea, the virtual object with eye cornea parameter was formed and imaged in the CCD image sensor through optical system processing. Binary image was divided up by DSP TMS320F2812, and diopter parameter of eye cornea was calculated with interpolation algorithm. The experiment was carried through by using the eye analogue with standard cornea, and comparison to refractor with model number TPCON KR-8100 made in Japan, results show both measurement error is less than ~0. 02 mm which is minimum error of diopter prescribed by national metrology bureau, and measurement precision attain subpixel.