• Survey on Non-photo realistic rendering - [Non-photo realistic rendering]

    " Abstract
    The survey is done for some Non-photorealistic rendering (NPR) techniques. The main focus is on 3D scientific illustraction area. NPR belongs to the area of computer graphics that focuses on enabling a wide variety of expressive styles for digital art. Three different NPR techniques are studies through out this survey, and they are PEL [1], Suggestive contours[2], and the stippling system [3]. This report presents the survey result and conclusion and future work are also included."

    ......

    " IV.    CONCLUSIONS AND FUTURE WORK

    4.1. Conlusions

    Scientific illustration has proven to be an effective means to represent the important scientific data. Illustrations take advantage of human visual acuity and can represent large amount of information in a relatively succinct manner. Due to the fact that the scientific illustration are greatly demanded across various industrial domains and its strong educational and communicative ability are well recognised, scientists have explored various possibilities to make the computer generated illustration more effective and accurate in the past 10 years. The selected 3 papers have provided three different approaches been carried out in this research area. The three approaches, PEL, suggestive contours, and stipple rendering , have been proven to be effective NPR techniques for scientific illustration.

    Looking at the PEL techinique, it does not support for real-time interaction. The processing speed is mainly affected by the expensive calculation of iso-surface extraction. In order to make PEL achieve real time interatcion, study on calculating PEL from volumetric datasets directly should be carried out, instead of using iso-surface extraction approach.

    Greater robustness is required in computing suggestive contours in object space. Objects without concavities have no suggestive contours.Ridges may be useful to overcome the problem. Suggestive Contours techniques can be applied in Dynamic Scene. The Paper[22] has provided one possibility of the suggestive contour can be developed in the future.

    The stippling system has limited interactivity. Hence the interactivity can be furthur improved. Since the current system is using volumne based rendering, experiment on applying point-based rendering can be done in the future to explore the possibility to improve the effectiveness of the performance.

    4.2. Some other NPR applications and future work

    Papers covered in this survey are mainly focusing on implementing application for the 3D scientific illustration. Bare in mind that NPR technique actually has a broader meaning and use. Thoughts on NPR should not only limited on 3D scientific illustraction.
    There are also applications created for simulating traditional artistic media such as watercolor and ink painting. Painterly rendering is one hot research topic. Through out all these various techniques, even though the topics can be on automatic process of producing “art” or “paintings”, I think most

    importantly we need to note that most of the techniques are not candidates for true artificial creativity (intelligence). Hence, future work on studying artifical creativity and to combine it with the NPR technique to achieve real automatic process of producing art can also be carried out. "

    -----------------------------------------------------------------------------------------------------

    The download link of my survey:

    http://www.ntu.edu.sg/home5/yang0074/NPRSurvey.rar