Benefits and Limitations using Multi Feature Test Charts

摘要

Many times when digital cameras are tested time is short. May it be because the test is performed on a production line where productivity is one of the most important aspects or in a lab where a schedule needs to be met. To reduce testing time one of the important aspects is to reduce the amount of images that need to be taken and analyzed. This can be achieved by combining different features into a single test target.rnAnother reason to use combined targets is to eliminate any shot to shot variations in exposure, focus setting, or image processing. Last but not least a single target may be cheaper than buying several targets for the different image quality aspects.rnBut when different features are incorporated into a single chart a couple of questions arise. Can the different aspects be determined independently? Is it better to use a transparent or a reflective target? Can e.g. a reflective chart with its limited contrast be used to measure the dynamic range of a camera? This paper discusses the pros and cons of combined test charts. It describes the related possibilities and problems for the main aspects of image quality like OECF, resolution, color reproduction, shading, and distortion. Application specific possibilities are studied and summarized.