A Novel Image Mosaicking Technique for Enlarging the Field of View of Images Transmitted over Wireless Image Sensor Networks

Abstract

Existing image mosaicking algorithms generate a complete scene that incorporates a number of images captured by several cameras. The traditional image mosaicking approaches cannot be applied directly to the emerging Wireless Image Sensor Networks (WISNs), since the low performance of image transmission over wireless sensor networks causes a noticeable delay before an entire image is received by a control center node. In this work, we propose a Progressive Image Mosaicking Algorithm (PIMA) based on the multi-scan feature of Progressive JPEG (P-JPEG). The originality of PIMA is based essentially on how it successfully performs mosaicking by using incremental image quality, as opposed to traditional methods that require complete data from all images. PIMA builds mosaics of images that are decoded from P-JPEG scans at three levels of quality, and delivers an approximate view of the scene in a short time while the reception of further image data is still in progress. Thereafter, it updates the image registration on two other refined levels to gradually enhance the display quality. We also propose the concept of Richer Information and Likeliest (RIL) block pair, which is a variation of the Sum of Absolute Difference (SAD). RIL can improve significantly the accuracy of image registration. We have conducted an extensive set of experiments and evaluated our proposed schemes against selected existing approaches. Our performance results indicate that PIMA decreases the delay before the first display of the scene, while preserving equivalent performance and image quality when compared to existing patch-based image mosaicking algorithms.