Results 161 to 170 of about 8,721,507 (209)

Sampling for Shape from Focus in Optical Microscopy

IEEE Transactions on Pattern Analysis and Machine Intelligence, 2012
Shape from focus (SFF), which relies on image focus as a cue within sequenced images, represents a passive technique in recovering object shapes in scenes. Although numerous methods have been recently proposed, less attention has been paid to particular factors affecting them.
Mannan Saeed, Muhammad, Tae-Sun, Choi
openaire   +2 more sources

A novel measurement method and application for grinding wheel surface topography based on shape from focus

Measurement, 2019
The precision measurement of grinding wheel topography is of great significance for accurate evaluating grinding performance and improving the workpiece surface finish and grinding efficiency.
J. Tang, Z. Qiu, Tianyi Li
semanticscholar   +1 more source

Shape from focus using multilayer feedforward neural networks

IEEE Transactions on Image Processing, 2001
The conventional shape-from-focus (SFF) methods have inaccuracies because of piecewise constant approximation of the focused image surface (FIS). We propose a scheme for SFF based on representation of three-dimensional (3-D) FIS in terms of neural network weights.
Asif, Muhammad, Choi, Tae-Sun
openaire   +3 more sources

Combining Focus Measures through Genetic Algorithm for Shape from Focus

2014 International Conference on Information Science & Applications (ICISA), 2014
For the reconstruction of three-dimensional (3D) shape of microscopic objects different focus measure operators have been employed. It is difficult to compute accurate depth map using a single focus measure due to different type of texture. Moreover, real images with diverse types of illumination and contrast lead to the erroneous depth map estimation ...
Muhammad Kaleem, Muhammad Tariq Mahmood
openaire   +1 more source

Image focus volume regularization for shape from focus through 3D weighted least squares

Information Sciences, 2019
In shape from focus (SFF) methods, the accuracy of the depth map highly depends on the quality of image focus volume. Generally, a linear filtering or averaging using a 2D mask is applied on each slice of the focus volume to filter out the noisy focus ...
Usman Ali, Vitalii Pruks, M. Mahmood
semanticscholar   +1 more source

Nonlinear Approach for Enhancement of Image Focus Volume in Shape From Focus

IEEE Transactions on Image Processing, 2012
Mostly, shape-from-focus algorithms use local averaging using a fixed rectangle window to enhance the initial focus volume. In this linear filtering, the window size affects the accuracy of the depth map. A small window is unable to suppress the noise properly, whereas a large window oversmoothes the object shape.
Muhammad Tariq, Mahmood, Tae-Sun, Choi
openaire   +2 more sources

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

Microscopic shape from focus with optimal illumination

CVPR 2011 WORKSHOPS, 2011
We present a novel method for compensating illumination artifacts in shape from focus reconstruction that does not require additional measurement time. Frequently applied in optical microscopy, shape from focus requires rich surface texture over the whole scene. This prerequisite is violated in saturated image regions.
Martin Lenz, Matthias Ruther, Horst Bischof   +2 more
openaire   +1 more source

Improving Shape from Focus Using Defocus Information

18th International Conference on Pattern Recognition (ICPR'06), 2006
Shape from focus (SFF) method determines the degree of focus in a sequence of observations to estimate the shape of a 3-D object. Existing SFF algorithms use an ad hoc interpolation strategy to account for the error due to the finite step-size by which the translational table is moved while capturing the images.
K.S. Pradeep, A.N. Rajagopalan
openaire   +1 more source

A higher performance shape from focus strategy based on unsupervised deep learning for 3D shape reconstruction

Multimedia tools and applications, 2023
Hülya Dogan
semanticscholar   +1 more source