We report on a fast image enhancement technique using a new scanning path for critical dimension (CD) measurement of glass panels. To improve the performance of low magnification microscope objectives used in glass panel inspection, sub-stepping systems are applied to increase the image resolution. In the sub-stepping system, low resolution (LR) images are obtained when the camera is moved at a step which is smaller than the normal pixel, and an XY piezo scanner is used for precise movement of the camera so that LR images can be interlaced to generate the desired high resolution (HR) image. A new scanning path is proposed and a fast interpolation algorithm based on the local pixel gradient is developed to shorten processing time. Our experimental results prove that the proposed path can replace the usual 9-step path to offer faster processing time and acceptable repeatability.