A novel approach to imaging using a dual field-of-view sensor

Abstract

Most modern aircraft, such as missile systems and unmanned aerial vehicles have limited size, weight, power and cost (SWaP-C) capability. As the defence budget for military forces such as the UK and US continue to shrink, the emphasis on SWaP-C continues to strengthen. Military forces require smart weapons capable of precision strike, with a priority on safety. System manufacturers understand these requirements and limitations, and in response, develop miniaturised systems and components and also aim to consolidate these, into a single miniaturised solution. The growth of remotely operated aircraft, offers an ever present need for better, cheaper imaging systems. In general, sensors and seekers tend to be the biggest contribution to the cost and weight of an aircraft. Often, multiple imaging systems are needed dependent on the operational requirements. In this thesis, a novel dual field-of-view imaging system/seeker is proposed, which uses a single imaging sensor to superimpose both a wide field-of-view and a narrow field-of-view image of the same scene, co-boresighted. This allows multiple operational requirements to function simultaneously. The wide field-of-view allows for continuous monitoring and surveillance of an area, whilst the narrow field-of-view enables target detection, identification and tracking capabilities. Secondly, this thesis proposes a novel image separation technique to facilitate the separation of the superimposed imagery, using only the geometric relationship between the two different field-of-views. The separation technique is then extended to operate over sequential frames (i.e. video), and to function with fixed cameras that exhibit (un)desired camera motions, such as vibrations or jitter. The image quality of the separation technique is broadly analysed over a range of images with varying image characteristics and properties. A novel image quality metric (IQM) was also proposed in this thesis, and was used to analyse the image quality of the recovered images, and its performance compared to already available IQMs. Finally, the separation technique is enhanced to operate with motion cameras, which exhibit motions such as pan, tilt, zoom and rotate etc. The separation technique, in most cases, was found to provide image recovery, comparable to current image enhancement techniques, and moreover, found to be far more robust to errors in registration, compared to current techniques. Initial hardware designs for the dual field-of-view imaging system, designed in conjunction with Prof. Andy Harvey from the University of Glasgow and Dr. James Babbington from Qioptiq Ltd., a lens design and manufacturing company, has also been presented.