Measurement of Texture Loss for JPEG 2000 Compression

摘要

The capture and retention of image detail are important characteristics for system design and subsystem selection. An established imaging performance measure that is well suited to certain sources of detail loss, such as optical focus and motion blur, is the Modulation Transfer Function (MTF). Recently we have seen the development of image quality methods aimed at more adaptive operations, such as noise cleaning and adaptive digital filtering. An example of this is the measure of texture (image detail) loss using sets of overlapping small objects, known as dead leaves targets. In this paper we investigate the application of the above method to image compression. We apply several levels of JPEG and JPEG 2000 compression to digital images that include scene content that is amenable to the texture loss measure. A modified form of the method was used. This allowed direct target compensation without data smoothing. Following a camera simulation, the texture MTF and acutance were computed. The standard deviation of the acutance measure was 0.014 (relative error of 1.63%), found by replicate measurements. Structured similarity index (SSIM) values, used for still and video image quality evaluation, were also computed for the image sets. The acutance and SSI results were similar; however the relationship between the two showed an offset between the JPEG and JPEG 2000 images sets.