The depth-of-field of the human eye from objective and subjective measurements
نویسندگان
چکیده
The depth-of-field (DOF) measured through psychophysical methods seems to depend on the target's characteristics. We use objective and subjective methods to determine the DOF of the eye for different pupil diameters and wavelengths in three subjects. Variation of image quality with focus is evaluated with a double-pass technique. Objective DOF is defined as the dioptric range for which the image quality does not change appreciably, based on optical criteria. Subjective DOF is based on the accuracy of focusing a point source. Additional DOFs are obtained by simulation from experimental wavefront aberration data from the same subjects. Objective and subjective measurements of DOF are only slightly affected by pupil size, wavelength and spectral composition. Comparison of DOF from double-pass and wavefront aberration data allows us to evaluate the role of ocular aberrations and Stiles-Crawford effect.
منابع مشابه
Ultrasonographic findings of some ocular structures in Caspian miniature horse
Ultrasonography is a relatively easy, safe and non-invasive examination method which can be used in diagnosis of ocular disorders as complementary to routine ophthalmic examinations. As there has been no collated study undertaken on the normal measurements of ocular structures in Caspian miniature horse, obtaining these measurements could be a benchmark to diagnose some of the diseases and eye ...
متن کاملComparison of Transcorneal and Transpalpebral Ultrasonographic Measurements of the Eye in Iranian Mix Breed Dog
Objective-The aim of this research was to compare transcorneal and transpalpebral ultrasonography study of the dimensions (ecobiometry) and the ultrasonographic aspect of Iranian mix breed dogs.Design- Experimental studyAnimals- . Ten adult male dogsProcedure- Ten adult male dogs with the mean age 4±1.39 years...
متن کاملAssessment of variation of wedge factor with depth, field size and SSD for Neptun 10PC Linac in Mashhad Imam Reza Hospital
Background: In radiotherapy, wedge filters are used for optimizing the tumor dose distribution in patients. The attenuation in beam intensity due to the presence of wedge filter is compensated by means of a wedge factor measured at the central axis of the beam. The field size, depth and SSD dependence of wedge factor have been assessed for 9MV radiations of Neptun PC linear accelerator. Materia...
متن کاملNew electrical device for field coincidence quality control test in linear accelerators
Testing of the coincidence of a linear accelerators X-ray field and the light field as a quality control test is often done in a subjective method, involving the manual marking of pieces of film and the visual inspection of the film after irradiation. The purpose of this study was to develop an objective method for performing this test, while also increasing the accuracy, precision and the spee...
متن کاملThe comparison of absorbed dose measurements for water and artificial body fluid
Background: Advances in radiation dosimetry concepts and the development of primary measurement standards based on absorbed dose to water over the last decades offer the possibility to calibrate ionisation chambers directly in terms of absorbed dose to water. The aim of this study is the investigation on utility of artificial body fluid (ABF) instead of water by comparing dosimetric me...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Vision Research
دوره 39 شماره
صفحات -
تاریخ انتشار 1999