Subpixel rendering

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

Significance and attributes of subpixel estimation on area-based matching

Abstract: Area-based matching and subpixel displacement estimation using similarity measures are common methods used in various fields. Subpixel estimation using parabola fitting over three points with their similarity measures is also a common method to increase matching resolution. However, such estimation can contain systematic error depending on image characteristics, the similarity function, and the fitting function used for subpixel estimation. In this paper, characteristics of subpixel estimation error were clarified using a simple analytical model. Although this model is quite simple, it allows us to make a theoretical analysis for general images without assuming any specific image pattern. Through this analysis, it has been shown that there are correct combinations of the similarity functions and the fitting functions. Also, the so-called “pixel-locking” effect, by which estimated positions tend to be biased toward integer values, has been explained. Finally, analyses were verified with an experiment using real images. © 2003 Wiley Periodicals, Inc. Syst Comp Jpn, 34(12): 1–10, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/scj.10506

Hardware Accelerated Voxel Carving

Abstract: In this paper we present a fast hardware accelerated volumetric method for the reconstruction of real world objects from a set of calibrated images. The approach is based on carving a bounding volume using a color similarity criterion. The algorithm is designed to use hardware accelerated features from the videocard. Moreover, the data structures have been highly optimized in order to minimize run-time memory usage. Additional techniques such as hardware texture mapping and shadow polygons are used to avoid redundant calculations. Hardware texture mapping is also used to reach subpixel precision. Moreover, if the image data can be segmented into foreground and background, a real time implementation of the visual hull algorithm is added to achieve a substantial reduction in computation time. Experimental results are presented on both synthetic and real imagery, showing excellent visual quality of the volumetric reconstruction.

Minimum variance unbiased subpixel centroid estimation of point image limited by photon shot noise

Abstract: An unbiased subpixel centroid estimation algorithm of point image is proposed through the compensation of the systematic error of the center of mass method. The Cramer-Rao lower bound on centroid estimation variances is derived under the photon shot noise condition and is utilized to evaluate the proposed algorithm. Numerical analysis shows that the proposed centroid estimator attains the required lower bound; thus the proposed algorithm can be asserted as a minimum variance estimator. Simulation results indicate that the centroid accuracy is maximized when the Gaussian width of the signal spot is 0.2-0.3 pixel and the estimator can attain subpixel accuracy close to 1/100 pixel when 1000 photons are detected.

Autostereoscopic 3D display using directional subpixel rendering

Abstract: In this paper we present an autostereoscopic 3D display using a directional subpixel rendering algorithm in which clear left-right images are expressed in real time based on a viewer's 3D eye positions. In order to maintain the 3D image quality over a wide viewing range, we designed an optical layer that generates a uniformly distributed light field. The proposed 3D rendering method is simple, and each pixel processing can be performed independently in parallel computing environments. To prove the effectiveness of our display system, we implemented 31.5" 3D monitor and 10.1" 3D tablet prototypes in which the 3D rendering is processed in the GPU and FPGA board, respectively.

Subpixel X-Y coordinate encoding

Abstract: A technique of encoding digitized video input signals to an arrayed display memory in a manner to maximize the probability of entering the best picture element (pixel) value into a particular X,Y location by effectively dividing a pixel area into an array of subpixels, and weighting the value of pixel as a function of the position of a display vector through the subpixel array. First the location of a vector to be displayed in an X-Y coordinate system is determined, and then with respect to the subpixel array of each pixel, it is determined whether the vector traverses a core or central area, an edge or a corner. For these respective vector locations, the pixel value is weighted, for example, 100%, 50% and 0%.