Subpixel rendering

About: Subpixel rendering is a research topic. Over the lifetime, 3885 publications have been published within this topic receiving 82789 citations.

Improved Bichromatic Display

Abstract: A display system includes a subpixelated display panel having subpixels in two saturated primary colors. In one embodiment, the primary colors are selected so as to be a substantially metameric pair for an achromatic color such as white. Information display efficiencies arise from utilizing a checkerboard arrangement for the two primary colored subpixels and from using subpixel rendering algorithms to render an image on the display. The bichromatic display may display a black and white image combined with a monochromatic image, or may provide the capability to overlay a first image from a first image source carried on a chromatic channel onto a second image from a second image source carried on a luminance channel, where the first image source detects light wavelengths that the Human Vision System is not sensitive to, such as infrared light. This latter embodiment of the bichromatic display system is suitable for night vision devices.

Robust and fast computation of unbiased intensity derivatives in images

Abstract: In this paper we develop high order non-biased spatial derivative operators, with subpixel accuracy. Our approach is discrete and provides a way to obtain some of the spatio-temporal parameters from an image sequence. In this paper we concentrate on spatial parameters.

Motion detection in image sequences acquired from a moving platform

Abstract: A two-step motion segmentation algorithm for the detection of moving objects in image sequences acquired from a moving platform is presented. First, the image plane transformation induced by the moving platform is estimated using a subpixel accuracy image registration algorithm. The registration algorithm is fully automatic and performs well under significant camera rotation and translation. The input images are then transformed into a common coordinate system (for example, the coordinate system of the first image). One then segments the changed regions from the camera motion-compensated frame difference. Finally, the moving object is detected from the closure of changing segments, and the object motion parameters are estimated. Experimental results for real image sequences are presented. >

Determination of the eROSITA mirror Half Energy Width (HEW) with subpixel resolution

Abstract: The Point Spread Function (PSF) of the eROSITA miror modules is specified to have an on-axis Half Energy Width (HEW) of 15 arcsec. This is only slightly larger than the eROSITA pixel size of 75 microns, which corresponds to 9.6 arcsec at the PANTER test facility, where the PSF is being measured with a prototype of the eROSITA CCD. We have developed a fast algorithm which provides a substantially higher spatial resolution by utilizing the information contained in the charge ratios of split events. By applying this algorithm to measurements where the CCD is systematically shifted in subpixel increments (typically in a 12x12 pattern), we are able to achieve an effective resolution of ~2 arcsec for specific pixel patterns. This algorithm can also be used to compute the two dimensional probability distribution for detecting a photon from an incident point-like beam, for each combination of photon energy, low energy threshold, selected pixel patterns, and subpixel scan properties. These maps allow us to deconvolve the measured PSF and thus to minimize the influence of the spatial detector resolution on the determination of the eROSITA mirror HEW. After launch, the algorithm for improving the spatial resolution by reconstructing the subpixel position will also be applied to the science data.

SHARE 2012: Subpixel detection and unmixing experiments

Abstract: The quantitative evaluation of algorithms applied to remotely sensed hyperspectral imagery require data sets with known ground truth. A recent data collection known as SHARE 2012, conducted by scientists in the Digital Imaging and Remote Sensing Laboratory at the Rochester Institute of Technology together with several outside collaborators, acquired hyperspectral data with this goal in mind. Several experiments were designed, deployed, and ground truth collected to support algorithm evaluation. In this paper, we describe two experiments that addressed the particular needs for the evaluation of subpixel detection and unmixing algorithms. The subpixel detection experiment involved the deployment of dozens of nearly identical subpixel targets in a random spatial array. The subpixel targets were pieces of wood painted either green or yellow. They were sized to occupy about 5% to 20% of the 1 m pixels. The unmixing experiment used novel targets with prescribed fractions of different materials based on a geometric arrangement of subpixel patterns. These targets were made up of different fabrics with various colors. Whole pixel swatches of the same materials were also deployed in the scene to provide in-scene endmembers. Alternatively, researchers can use the unmixing targets alone to derive endmembers from the mixed pixels. Field reflectance spectra were collected for all targets and adjacent background areas. While efforts are just now underway to evaluate the detection performance using the subpixel targets, initial results for the unmixing targets have demonstrated retrieved fractions that are close approximations to the geometric fractions. These data, together with the ground truth, are planned to be made available to the remote sensing research community for evaluation and development of detection and unmixing algorithms.