Radial distortion in an image is a geometric distortion that causes a non-linear variation in resolution across the image, with a higher spatial resolution in the central areas of the image, and lower resolution in the peripheral areas of the image. This is particularly evident in fish-eye cameras, with very wide fields-of-view. Equidistant fish-eye cameras are designed such that the distance b...

Magnetic Resonance Imaging (MRI) is increasingly being used for improving tumor delineation and tumor tracking in the presence of respiratory motion. The purpose of this work is to design and build an MR compatible motion platform and to use it for evaluating the geometric accuracy of MR imaging techniques during respiratory motion. The motion platform presented in this work is composed of a mo...

After an image is printed-and-scanned, it is usually filtered, rotated, scaled, cropped, contrast-andluminance adjusted, as well as distorted by noises. This paper presents models for the print-and-scan process, considering both pixel value distortion and geometric distortion. We show properties of the discretized, rescanned image in both the spatial and frequency domains, then further analyze ...

We propose scveral new techniques for mosaic-ing images of Japanese picture scrolls. Previous methods cannot accurately stitch these images, because they are too wide. To solve this problem , we propose three techniques that can stitch without any seams. The first technique adjusts its height of each image in advance. The second technique uses planar projective transformation among three images...

When visual features in the periphery are close together they become difficult to recognize: something is present but it is unclear what. This is called "crowding". Here we investigated sensitivity to features in highly familiar shapes (letters) by applying spatial distortions. In Experiment 1, observers detected which of four peripherally presented (8 deg of retinal eccentricity) target letter...