On defocus, diffusion and depth estimation

Namboodiri, Vinay P.; Chaudhuri, Subhasis

doi:10.1016/j.patrec.2006.04.011

Cited by 60 publications

(20 citation statements)

References 20 publications

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“…Depth from de/focus algorithms [9] rely on the principle that the Gaussian blurring of an out of focus object can be modeled such that the point spread function (psf) may be estimated [8]. By capturing two or more images it may be possible to use this information to identify the distance between the lens and the object.…”

Section: Depth From De/focusmentioning

confidence: 99%

Label free cell tracking in 3D tissue engineering constructs with high resolution imaging

et al. 2014

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Within the field of tissue engineering there is an emphasis on studying 3-D live tissue structures. Consequently, to investigate and identify cellular activities and phenotypes in a 3-D environment for all in vitro experiments, including shape, migration/proliferation and axon projection, it is necessary to adopt an optical imaging system that enables monitoring 3-D cellular activities and morphology through the thickness of the construct for an extended culture period without cell labeling. This paper describes a new 3-D tracking algorithm developed for Cell-IQ®, an automated cell imaging platform, which has been equipped with an environmental chamber optimized to enable capturing time-lapse sequences of live cell images over a long-term period without cell labeling. As an integral part of the algorithm, a novel auto-focusing procedure was developed for phase contrast microscopy equipped with 20x and 40x objectives, to provide a more accurate estimation of cell growth/trajectories by allowing 3-D voxels to be computed at high spatiotemporal resolution and cell density. A pilot study was carried out in a phantom system consisting of horizontally aligned nanofiber layers (with precise spacing between them), to mimic features well exemplified in cellular activities of neuronal growth in a 3-D environment. This was followed by detailed investigations concerning axonal projections and dendritic circuitry formation in a 3-D tissue engineering construct. Preliminary work on primary animal neuronal cells in response to chemoattractant and topographic cue within the scaffolds has produced encouraging results.

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Section: Depth From De/focusmentioning

confidence: 99%

Label free cell tracking in 3D tissue engineering constructs with high resolution imaging

et al. 2014

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“…As the distance variation is calibrated, points from different depth slices can be combined to a depth map. Depth from defocus [6] is a single-view method which makes use of the knowledge about the point spread function of the optical system to deduce depth from unsharpness.…”

Section: Previous Workmentioning

confidence: 99%

Reading from Scratch – A Vision-System for Reading Data on Micro-structured Surfaces

Dragon

Becker

Rosenhahn

et al. 2009

Lecture Notes in Computer Science

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Abstract. Labeling and marking industrial manufactured objects gets increasingly important nowadays because of novel material properties and plagiarism. As part of the Collaborative Research Center 653 which investigates micro-structured metallic surfaces for inherent mechanical data storage, we research into a stable and reliable optical readout of the written data. Since this comprises a qualitative surface reconstruction, we use directed illumination to make the micro structures visible. Then we apply a spectral analysis to obtain image partitioning and perform signal tracking enhanced by a customized Hidden Markov Model. In this paper, we derive the algorithms used and demonstrate reading data from a surface with 1.6 kbit/cm 2 from a micro-structured groove which varies by only 3 µm in depth (thus a "scratch"). We demonstrate the system's robustness with experiments with real and artificially-rendered surfaces.

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“…Compared to DFS and DFF, DFD requires less images, no match and occlusion between images, and the operation is simple. The traditional DFD methods require at least two defocused images with different camera parameters to calculate depth information using the relationship between burring degree and depth [1][2][3][4]. Therefore, two cameras with different camera parameters or a camera with two parameter adjustment sets are required.…”

Section: Introductionmentioning

confidence: 99%

Distance Calculation from Single Optical Image

Duan¹,

Wei²,

Zhang³

2018

dtcse

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Abstract. Accurate and fast distance calculation with respect to a single optical image is useful for real-time 3D construction and acquisition, however currently rare distance calculation methods theoretically base on an optical single image, and the traditional distance calculation method with a single image has limitations due to assumption that the step edge in the image must be strictly horizontal or vertical, which is difficult to fulfill in real applications because the slope of a practical edge could be any other value except for zero and infinity. In this paper, a distance calculation method with a single defocused image containing an oblique step edge is proposed, and no special camera equipment or unique external condition is required. First, the basic theory of coordinate system rotation has been introduced to simplify the sampling process of neighbor points and eliminate the influence resulted from slope of the step edge; one-dimension point-spread-function of the original distance calculation method is expended to two-dimension, taking into account coordinate transform, and a comprehensive distance calculation based on an oblique step edge with any slope is deduced; The relationship between the precision of distance calculation and the slope of the step edge is analyzed and proved in theory. Finally, a serial of simulation are conducted to validate our proposed distance calculation method, and the experimental results prove the applicability, validity and high precision of our method.

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On defocus, diffusion and depth estimation

Cited by 60 publications

References 20 publications

Label free cell tracking in 3D tissue engineering constructs with high resolution imaging

Label free cell tracking in 3D tissue engineering constructs with high resolution imaging

Reading from Scratch – A Vision-System for Reading Data on Micro-structured Surfaces

Distance Calculation from Single Optical Image

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