This paper presents an improved finite ridgelet transform (IMFRIT) approach to linetype structure image denoising. The key element of this technique is an improvement of the finite Radon transform, whereby the transform is defined on non-square grid rather than on square one. A linetype structure denoising algorithm, which utilizes IMFRIT, is then developed. In this algorithm, referred to as the slice-based IMFRIT (SIMFRIT) algorithm, the image is first divided into several slices, and then IMFRIT denoising is performed on each slice. Experiment results show that our approach can significantly reduce the "wrap-around" effect which is an annoying problem in FRIT, and well preserve edges at the same time