This paper describes an efficient method of generating a model-based system matrix using Monte Carlo simulation for incorporation into reconstruction algorithms for pinhole SPECT imaging and reconstructions. The method is able to model the imaging geometry for pinhole collimators and the detector depth of interaction effect accurately and efficiently, and has demonstrated improvement in the qua...

ception, and cognitive courses, as well as introductory courses, and can implement the demonstration in lecture or in a laboratory assignment in which students manipulate the lens and screen themselves. Instructors may even assign the construction of a classroom-sized or traditional-sized pinhole camera as a class project. Regardless of how instructors choose to use it, we conclude that the pin...

BACKGROUND A prototype anthropomorphic head and neck phantom has been designed to simulate the adult head and neck anatomy including some internal organs and tissues of interest, such as thyroid gland and sentinel lymph nodes (SLNs). The design of the head and neck phantom includes an inner jig holding the simulated SLNs and thyroid gland. The thyroid gland structure was manufactured using thre...

A very important property of the usual pinhole model for camera projection is that 3D lines in the scene are projected to 2D lines. Unfortunately, wide-angle lenses (specially low-cost lenses) may introduce a strong barrel distortion, which makes the usual pinhole model fail. Lens distortion models try to correct such distortion. In reference 1., we propose an algebraic approach to the estimati...

In single photon emission computed tomography (SPECT), pinhole and cone-beam collimators are used for small object imaging. It is accepted that a pinhole collimator should be used if the object is very small, and the cone-beam collimator should be used if the object is larger. This paper presents criteria to determine which collimation geometry is more advantageous in terms of spatial resolutio...

We begin by considering the process of image formation when a scene is viewed through a camera. The word camera has its origins in the Latin camera and the Greek kamara, both of which refer to a room or a chamber. In particular we will consider image formation through a pinhole camera. This is the dominant image formation model that is studied in computer vision. A pinhole camera is a box in wh...

A pinhole camera selects a two-dimensional set of rays from the four-dimensional light field. Pinhole cameras are a type of general linear camera, defined as planar 2D slices of the 4D light field. Cameras with finite apertures can be considered as the summation of a collection of pinhole cameras. In the limit they evaluate a two-dimensional integral of the four-dimensional light field. Hence a...