Line Drawing for Conveying Shapes in HDR Images

In this paper, we present NPR techniques to convey important shapes in HDR images. Line drawing is important to convey shapes in an image to produce good illustrations for scientific purpose. The proposed method make use of the global tone mapping operator, 2D anisotropic filter, 2D modified coherence shock filter, weight parsing technique and bilateral filtering. Global tone mapping operator is used to suppress the high luminance image region and helpful to convert HDR images to LDR images. 2D Anisotrophic filter preserves the local structure orientation features and suppresses the severe noises. Weight parsing technique is used to highlight the outline boundary. Coherence shock filter is applied iteratively to enhance the edge information in an image. Bilateral filter with a fixed deviation value is also applied to preserve the boundary in the line drawing image. The proposed method has been experimented on HDR images, images with complex or cluttered background and does not require any kind of post processing techniques for line drawing. Implementation of the proposed work is carried out in MATLAB environment. Efficiency of the proposed work has been corroborated by conducting different experiments on various types of images and the results are compared with other contemporary work. The approach is found to be computationally efficient in producing effective line drawing for human visual system (HVS)..