Image Bloom Testing and Analysis

摘要

The performance of imaging systems continues to increase and diversify as a result of the ability to measure, analyze, and improve the limiting aspects of imaging systems. Bloom is one such limiting aspect. In an image, bright regions of light noticeably bleed into darker regions of light causing the phenomenon referred to as "bloom". The occurrence of bloom is theoretically a direct consequence of the diffraction pattern of an aperture. In practice, bloom is caused both optically by non-ideal lenses and electronically by the bleeding of overly saturated pixels. In analyzing optical instruments, circular apertures are of particular interest since their theoretical diffraction patterns are well known, consisting of an Airy Disk and alternating concentric dark and bright rings. In the image formed by a circular aperture, relative intensity can be observed by dividing all pixel intensity values by the peak pixel intensity. Bloom cut off percentages may be analyzed from their relative distances to the threshold peak intensity. Instrument performance may thus be measured against theoretical Airy function values or by comparing different images produced by the same instrument under similar conditions. Additionally, polynomials of single digit orders may be accurately fit to the pixel array data. By approximating the data with polynomials, pertinent information on derivatives, local slopes, and integrals may be analytically as well as numerically obtained.