Computational filter-aperture approach for single-view multi-focusing

Most of the focusing techniques need to estimate depth information for ensuring that the object of interest is at an appropriate distance for full frontal focus. Computational cameras which can variably focus different regions of the scene with large depth of field have been proposed. In this paper we propose a full auto-focusing algorithm using computational camera without involving any digital image restoration methods and just one input. The proposed computational camera uses multiple filter apertures corresponding to each color channel which can acquire three shifted views of a scene in the RGB color planes. We can make any region focused by appropriately shifting each color channel to be aligned. Depth map estimation is carried out to extract different regions from these channel shifted images which is later fused to produce the final image without any focal blur. Experimental results show performance and feasibility of the proposed algorithm for auto-focusing images with one or more differently out-of-focused objects.

[1]  Tomoyuki Nishita,et al.  Extracting depth and matte using a color-filtered aperture , 2008, SIGGRAPH Asia '08.

[2]  Jun Tanida,et al.  Color imaging with an integrated compound imaging system. , 2003, Optics express.

[3]  Joonki Paik,et al.  Regularized Image Restoration by Means of Fusion for Digital Auto Focusing , 2005, CIS.

[4]  Stefano Soatto,et al.  Observing Shape from Defocused Images , 2004, International Journal of Computer Vision.

[5]  Frédéric Guichard,et al.  Extended depth-of-field using sharpness transport across color channels , 2009, Electronic Imaging.

[6]  Jungsoo Lee,et al.  Multi-object Digital Auto-focusing Using Image Fusion , 2005, ACIVS.

[7]  Kazuya Kodama,et al.  All-in-Focus Image Generation by Merging Multiple Differently Focused Images in Three-Dimensional Frequency Domain , 2005, PCM.

[8]  Tae-Sun Choi,et al.  Shape from focus using multilayer feedforward neural networks , 2000, IEEE Trans. Image Process..

[9]  Long Quan,et al.  Image deblurring with blurred/noisy image pairs , 2007, SIGGRAPH 2007.

[10]  Frédo Durand,et al.  Image and depth from a conventional camera with a coded aperture , 2007, SIGGRAPH 2007.

[11]  Edward R. Dowski,et al.  Wavefront coding: a modern method of achieving high-performance and/or low-cost imaging systems , 1999, Optics & Photonics.

[12]  D. Scharstein,et al.  A Taxonomy and Evaluation of Dense Two-Frame Stereo Correspondence Algorithms , 2001, Proceedings IEEE Workshop on Stereo and Multi-Baseline Vision (SMBV 2001).