Edward M. Granger

A Summary Measure Of Image Quality

The Fourier Transform of a line spread function, the O.T.F., can be accurately approximated by the moments of the line spread function. This relation is used to show that the second moment is an excellent single parameter estimate of a systems M.T.F. The second moment is easy to compute and offers many advantages in determining the performance of asymmetric imagery. The overall performance of the system can be predicted by a single universal image quality template.

Visual Limits To Image Quality

Todays high speed computers, large and inexpensive memory devices and high definition displays have opened up the area of electronic image processing. Computers are being used to compress,enhance,and geometrically correct a wide range of image related data. It is necessary to develop Image Quality Merit Factors (IOW) that can be used to evaluate, compare, and specify imaging systems. A meaningful IQMF will have to include both the effects of the transfer function of the system and the noise introduced by the system. Most of the methods used to date have utilized linear system techniques to describe performance. In our work on the IOMF, we have found that it may be necessary to imitate the eye-brain combination in order to best describe the performance of an imaging system. This paper presents the idea that understanding the organization of and the rivalry between visual mechanisms may lead to new ways of considering photographic and electronic system image quality and the loss in image quality due to grain, halftones, and pixel noise.

Wavefront Measurements From A Knife Edge Test

Wavefront measurements from a knife edge testEdward M. GrangerEastman Kodak Company, U.S. Apparatus Division, USAD Research Laboratory,901 Elmgrove Road, Rochester, New York 14650AbstractThe knife edge testing of optics is well known to be a sensitive but subjective test ofan optical system. This test has been successfully used to figure telescope mirrors to ahigh degree of perfection. The problem with this test was that it was difficult if notimpossible to get useful numbers as to the magnitude of error in the optic under test.With the advent of solid -state memory, microcomputers, and video sensors, we are now ableto collect the information required to quantify the data available from the knife edge trace.The key to the new knife edge bench is the use of solid -state memory to capture and storepupil data so that it can be processed by the microcomputer.The system being described uses Zernike polynomials to bridge the gap between thesubjective test and the objective measure. The Zernike polynomials are used to develop co-efficients from the knife position. These Zernike coefficients are then converted to wave -front by using straightforward matrix operations.TheoryThe wavefront determination from knife uses the Lagrange differential invariant which is

Beryllium scatter analysis program

Many groups today are researching the characteristics of beryllium, in an attempt to find ways of producing high quality (low scatter) stable beryllium optics. This paper discusses a two-part study in which (1) an attempt is being made to determine the best, raw beryllium mixture and preparation, machining and polishing processes, test and analysis methods, and (2) a proposed model for the prediction of scatter from beryllium surfaces (based on a knowledge of surface and subsurface interactions with incident wavelengths) will be refined against empirical data. We discuss design of the experiment, the model, and some of the early results.