Results 141 to 150 of about 562,132 (184)

Depth coded shape from focus

2012 IEEE International Conference on Computational Photography (ICCP), 2012
We present a novel shape from focus method for high-speed shape reconstruction in optical microscopy. While the traditional shape from focus approach heavily depends on the presence of surface texture, and requires a considerable amount of measurement time, our method is able to perform 3D reconstruction from only two images.
Martin Lenz, David Ferstl, Matthias Ruther, Horst Bischof   +3 more
openaire   +1 more source

Underwater Microscopic Shape from Focus

2014 22nd International Conference on Pattern Recognition, 2014
In this paper, we extend traditional Shape from focus (SFF) to the underwater scenario. Specifically, we show how 3D shape of objects immersed in water can be extracted from images captured under an optical microscope. Traditional SFF employs telecentric optics to achieve geometric registration among the frames. We extend conventional SFF to underwater
S. Karthik, A.N. Rajagopalan
openaire   +1 more source

Dealing With Parallax in Shape-From-Focus

IEEE Transactions on Image Processing, 2011
We propose a new method that extends the capability of shape-from-focus (SFF) to estimate the depth profile of 3-D objects in the presence of structure-dependent pixel motion. Existing SFF techniques work under the constraint that there is no parallax in the captured stack of frames.
Rajiv Ranjan, Sahay, A N, Rajagopalan
openaire   +2 more sources

Shape from focus for large image fields

Applied Optics, 2015
Shape from focus is a method for the accurate measurement of the geometrical shape of objects. The measurement principle is the local focus search. The method is suitable only for objects with a texture (optically rough surface). The longitudinal coordinate of a surface point is determined from the maximum of the focus measure function.
Pavel, Pavliček, Ivana, Hamarová
openaire   +2 more sources

Improving Shape From Focus Using Defocus Cue

IEEE Transactions on Image Processing, 2007
The shape-from-focus (SFF) method uses a sequence of frames to estimate the structure of a 3-D object. Its accuracy depends on the step size by which the translational table is moved while capturing the images. Existing SFF algorithms use an ad hoc interpolation strategy to account for the error due to the finite step size.
K S, Pradeep, A N, Rajagopalan
openaire   +2 more sources

Shape From Focus Using Optimization Technique

2006 IEEE International Conference on Acoustics Speed and Signal Processing Proceedings, 2006
Three dimensional (3D) shape recovery using shape from focus (SFF) is presented as an optimization problem, i.e., maximization of the focus measure in the 3D image volume. The whole image volume (sequence) is divided into a number of sub image volumes.
M.B. Ahmad, null Tae-Sun Choi
openaire   +1 more source

Shape from focus using statistics methods

2017 International Smart Cities Conference (ISC2), 2017
Shape from focus technique can be used in the computer monocular vision, which is widely applied in the smart transportation. In this study, we proposed a novel directional statistics based focus measure for shape from focus computation. We first compute the standard deviation σ and the mean value μ in the directional neighborhood.
Bo Jiang, Liqiang Guo, Fubing Chen
openaire   +1 more source

Shape from focus using kernel regression

2009 16th IEEE International Conference on Image Processing (ICIP), 2009
In conventional focus measures, focus values are locally aggregated to suppress the noise and to obtain better depth maps. However, this enlarges the difference between focus values of two consecutive frames which results in inaccurate shape. In this paper, we propose a nonparametric approach for 3D shape from image focus by applying an unsupervised ...
null Muhammad Tariq Mahmood, Tae-Sun Choi   +1 more
openaire   +1 more source

Shape from focus system

Proceedings 1992 IEEE Computer Society Conference on Computer Vision and Pattern Recognition, 2003
A shape-from-focus method that uses different focus levels to obtain a sequence of object images is described. A sum-modified-Laplacian operator is developed to provide local measures of the quality of image focus. The operator is applied to the sequence of images of the object to determine a set of focus measures as each image point.
openaire   +1 more source

Approximating shape from focus by averaging filter

SPIE Proceedings, 2009
The technique to estimate the depth and 3D shape of an object from the images of the same sample obtained at different focus settings is called shape from focus (SFF). Conventional SFF methods sum up the focus values within a small window of each pixel in the image. It produces a surface distortion effect, and an inaccurate depth map is obtained. In
Seong-O Shim, Tae-Sun Choi
openaire   +1 more source