Direct Volume Rendering (DVR) algorithm is an important method to display the three dimensional data and it is widly used in medical image rendering and sicentific visualization. Furthermore

ray casting method is a basic method of DVR algorithm. However

it is limited by plenty of computation. From the view of reducing the number of casted ray

this article provided an adaptive ray casting method based on the optional sampling pattern. The advantage of the algorithm is not only using the simple human vision model and powerful fourier analysis tools

but also making the advantage of the sampling pattern being more suitable to the human vision model and reducing the aliase pattern. As a result

more noise is changed to be more insensitive. So

this algorithm not only improves the image rendering quality

but also reduces the image rendering time.