Image Quality Assessment for Interdependent Image Parameters Using a Score-Based Technique for Endoscopy Applications

It is an arduous task to perform an Image Quality Assessment (IQA) for all real-time imaging systems like endoscopy systems which have no reference images for comparison. That being a challenge in itself, the images must be assessed subjectively rather than objectively so that the assessments comply with human perception. ImageLab, a complete IQA solution developed in-house has image capture and illumination capabilities integrated with custom test charts and algorithms to provide a detailed analysis for individual image parameters. Though individual parameter analysis is the primary focus of the IQA tool, a technique to provide a score for image quality based on the interdependency of the image parameters is also integrated in the tool. Specifically, the dependency of visual noise and dynamic range on sharpness and resolution has been highlighted in this paper. Eight levels of sharpness were chosen and for every level, image quality in terms of visual noise and dynamic range were computed. The perceived visual noise levels which is part of subjective analysis were factored in the dynamic range calculations and the final image quality score was derived. These detailed measurements would aid in the development of endoscopy systems and the much simpler score-based technique would aid the technicians during maintenance and calibration check before endoscopy examination.