Keystone aberration correction in overhead projectors.

Appl Opt

Centro de Investigaciones en Optica, A.C., Apartido Postal 1-948, 37000 Leon, Gto., Mexico.

Published: July 2004

Keystone distortion that occurs in overhead projectors when the projecting lens head is tilted upward to a high screen is commonly observed. Here we suggest a modification of the typical overhead projector to eliminate this distortion of the image.

Download full-text PDF

Source
http://dx.doi.org/10.1364/ao.43.004123DOI Listing

Publication Analysis

Top Keywords

overhead projectors
8
keystone aberration
4
aberration correction
4
correction overhead
4
projectors keystone
4
keystone distortion
4
distortion occurs
4
occurs overhead
4
projectors projecting
4
projecting lens
4

Similar Publications

In this paper, we report an inexpensive and easy-to-engineer flexible nanobiosensor electrode platform by exploring a nonconductive overhead projector (OHP) sheet for sweat Neuropeptide-Y (NPY) detection, a potential biomarker for stress, cardiovascular regulation, appetite, etc. We converted a nonconductive OHP sheet into a conductive nanobiosensor electrode platform with a hybrid polymerization method, which consists of interfacial polymerization of pyrrole and a template-free electropolymerization technique to decorate the electrode platform with poly(EDOT-COOH--EDOT-EG3) nanotubes. The selection of poly(EDOT-COOH) features an easy conjugation of NPY antibody (NPY-Ab) through EDC/Sulfo-NHS coupling chemistry, while poly(EDOT-EG3) is best known to reduce nonspecific binding of biomolecules.

View Article and Find Full Text PDF

Negative-Free Self-Supervised Gaussian Embedding of Graphs.

Neural Netw

January 2025

State Key Laboratory for Novel Software Technology, Nanjing University, Nanjing, 210023, China.

Graph Contrastive Learning (GCL) has recently emerged as a promising graph self-supervised learning framework for learning discriminative node representations without labels. The widely adopted objective function of GCL benefits from two key properties: alignment and uniformity, which align representations of positive node pairs while uniformly distributing all representations on the hypersphere. The uniformity property plays a critical role in preventing representation collapse and is achieved by pushing apart augmented views of different nodes (negative pairs).

View Article and Find Full Text PDF

Ultraviolet protection in eye and face protection against biological hazards.

Ophthalmic Physiol Opt

September 2024

School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia.

Background: In the development of eye and face protection standards against biological hazards, it is important to consider that the eye and face protectors may be used in the outdoor environment, where ultraviolet (UV) exposure from the sun is much higher than indoors. Workers affected include paramedics, ambulance officers and clinical testing personnel.

Methods: Spectral transmittances (280-780 nm) were measured on eight face shields and one goggle of the types used in hospital and clinical environments, three overhead projector sheets and an occupational impact protective goggle.

View Article and Find Full Text PDF

For over two centuries, the educational landscape both nationally and globally has changed tremendously. The more traditional teaching and learning resources and platforms, such as traditional textbooks, chalkboards and whiteboards, overhead transparency and carousel projectors, and traditional classroom settings, have been either replaced or supplemented in the anatomical sciences by integrated and virtual eBooks, online learning management (OLM) platforms, and virtual learning and meeting apps. Virtual teaching and learning, especially proliferated with the advent and aftermath of the COVID-19 pandemic, and institutions worldwide that had already been utilizing virtual class and lab sessions in their anatomy curricula expanded virtual course offerings.

View Article and Find Full Text PDF

With the advancement of digital technology, the medium in which medical education is delivered has evolved from chalk talks, to the use of overhead projectors, and now to a digital format. Although the old of a good chalk talk can still seize the attention of pupils and inspire, new methods continue to emerge. In recent years, artificial intelligence has materialized as a tool to advance the medical field, and medical education is no exception.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!