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John H Xin

Publications and source records attributed to John H Xin.

9 recordsLinked to original sources
PubMed2007

Estimation of spectral reflectance of object surfaces with the consideration of perceptual color space.

Due to the nonlinear transform from spectral reflectance to CIELAB values, the solution obtained by minimizing reflectance error in traditional spectral characterization methods will not be optimal when evaluated by colorimetric error. We propose a reflectance estimation method with consideration of perceptual color space. It combines two approaches, i.e., colorimetric-based spectral calculation and weighted spectral calculation. The experimental results show that the proposed method performs better than previous methods in terms of color difference with very slight degradation in spectral accuracy.

Journal Article↗
PubMed2006

Fabrication of UV-blocking nanohybrid coating via miniemulsion polymerization.

A novel convenient approach to fabricate ZnO@polystyrene nanohybrid coating on cotton fabrics is reported. The as-prepared core-shell nanohybrid coating was characterized by scanning electron microscope (SEM), transmission electron microscope (TEM), energy dispersive X-ray (EDX), and UV-blocking. The cotton fabrics treated in this study provided ultrahigh UV protection and superior wash fastness. Therefore, this new nanohybrid material and its synthesis method are highly potential to various functional treatments of flexible surfaces.

Journal Article↗
PubMed2006

Self-assembled gold nanoshells on biodegradable chitosan fibers.

A novel chitosan fiber core/gold shell structural organic-inorganic composite was presented via a facile and eco-friendly approach. The chitosan fiber and gold/chitosan composites were characterized with the assistance of scanning electron microscopy and transmission electron microscopy observations. The chitosan fibers used in this study were 50 nm to 5 microm in diameter and up to hundreds of micrometers in length. The gold shells were typically 20-50 nm in depth, and their lattice fringes obliquely intersecting at an angle of 60 degrees were displayed. The formation mechanism of the as-fabricated chitosan fiber core with gold as the shell structural composites was also schematically discussed.

Adsorption↗
PubMed2006

Spectral characterization of a color scanner based on optimized adaptive estimation.

A scanner characterization method is proposed to estimate spectral reflectance from scanner responses by using an optimized adaptive estimation method. In contrast to our previous study [J. Opt. Soc. Am. A21, 1125 (2004)], this method considers the weighting of training samples. It is demonstrated that the color accuracy of this method is only slightly affected by the number of training samples and can provide more accurate reflectance estimation.

Comment↗
PubMed2005

Analysis and synthesis of multicolored objects in a single image.

We present a method with which to recover the intrinsic shading and reflectance characteristics of multicolored three-dimensional objects in a single image, with which realistic new scenes can be synthesized. A color watershed algorithm, which is based on a regularized dichromatic fitting error, is proposed for robust image segmentation. For shading recovery in small regions, a weighted interpolation is employed, whereas in large regions the reflectance and shading are calculated based on the assumption of gradual shape variation. It is demonstrated that the proposed method is promising and can be applied in image simulation.

Journal Article↗
PubMed2005

Transferring color between three-dimensional objects.

A framework for transferring image-based color between three-dimensional objects by the use of a dichromatic reflection model is proposed. The framework addresses the following issues: (1) accurate recovery of an implicit geometric coefficient, (2) calculation of body color, (3) color transfer between different illuminants, and (4) segmentation of multicolored regions. The experimental results show that high color accuracy and photorealistic effects of the synthesized images can be achieved. The proposed technique has wide applications in image-based design and visualization of three-dimensional objects.

Algorithms↗
PubMed2004

Accurate color synthesis of three-dimensional objects in an image.

Our study deals with color synthesis of a three-dimensional object in an image; i.e., given a single image, a target color can be accurately mapped onto the object such that the color appearance of the synthesized object closely resembles that of the actual one. As it is almost impossible to acquire the complete geometric description of the surfaces of an object in an image, this study attempted to recover the implicit description of geometry for the color synthesis. The description was obtained from either a series of spectral reflectances or the RGB signals at different surface positions on the basis of the dichromatic reflection model. The experimental results showed that this implicit image-based representation is related to the object geometry and is sufficient for accurate color synthesis of three-dimensional objects in an image. The method established is applicable to the color synthesis of both rigid and deformable objects and should contribute to color fidelity in virtual design, manufacturing, and retailing.

Journal Article↗
PubMed2004

Spectral characterization of a color scanner by adaptive estimation.

A new method of spectral characterization for color scanners by the use of adaptive estimation is proposed. It deals with estimation of high-dimensional reflectance vectors from low-dimensional scanner response vectors when the scanner departs from linearity. We first investigate the spectral linearity of the scanner, and then estimate the spectral reflectance adaptively based on the local statistics of a set of neighboring training samples. As the proposed characterization method does not utilize the mathematically recovered spectral responsivity, its inherent inaccuracy is not critical to the spectral characterization. Experimental results showed significant advantage of adaptive estimation when compared with other methods.

Journal Article↗