We introduce a novel approach based on speckle pattern recognition with deep neural network, which is simpler and more robust than other nlos recogni. Speckle pattern synonyms, speckle pattern pronunciation, speckle pattern translation, english dictionary definition of speckle pattern. In digital image correlation, the quality of the data is often dependent on the quality of the speckle pattern. Espi can be used in arrangements where fringes will represent lines of either inplane or outofplane displacement. Early recognition of apical ballooning syndrome by global. We have used a new scheme of using the speckle patterns as the reference beam. Optical pattern recognition by using specklemultiplexed. The very particular properties of speckle and notably its fineness have led to the development of new techniques. The main difference between the three new images is thus the overall and random size. It uses by default the backspace as the backbutton.
Spatial entanglement gives twophoton speckle a much richer structure than ordinary onephoton speckle. Downie nasa ames research center, ms 2693, moffelt field, ca 94035, usa abstract logarithmic processing of images with multiplicative noise characteris tics can be. Morphology study of a given speckle pattern as an example, the speckle size distribution of speckle pattern a will be determined. The spatial character istics such as speckle size can be used to measure the roughness of surfaces 12.
Recognition of paper samples by correlation of their speckle patterns. Solutions to pattern recognition problems models for algorithmic solutions, we use a formal model of entities to be detected. Speckle artifacts degrade image quality in virtually all modalities that utilize coherent energy, including optical coherence tomography, reflectance confocal microscopy, ultrasound, and widefield imaging with laser illumination. Speckle pattern definition of speckle pattern by the. Osa scatterer recognition via analysis of speckle patterns. Line and boundary detection in speckle images richard n.
In order words, speckle detection becomes a twoclass pattern recognition problem. A speckle pattern is produced by the mutual interference of a set of coherent wavefronts. Model of light scattering by a rough surface consider the formation and measurement of a speckle pattern in. The speckle is caused by the interference of the laser. The term speckle refers to a random granular pattern which can be observed e. The hologram recorded with this speckled reference beam is less correlated with each other compared to the. Scatterer recognition via analysis of speckle patterns. We experimentally demonstrated object recognition through scattering media based on direct machine learning of a number of speckle intensity images. The two samples with the dense fine speckled dfs pattern were recognized with significantly lower accuracy. Laser speckle photography for surface tampering detection. Let us now go to the analysis of autocorrelation functions for the case. In general the statistical properties of a speckle pattern depend both on. We present an adversarial deep learning framework for laser speckle reduction, called deeplsr, that transforms images from a. Further inspection, however, reveals that the i speckles generated by the j illuminations i, j 1,2 are all.
In particular, the benchmarks include the fascinating problem of causal inference. Freeman, laser speckle photography for surface tampering detection. Most downloaded pattern recognition articles elsevier. Ieee conference on computer vision and pattern recognition cvpr, 2012. Finding causal directions from observations is not only a profound issue for the philosophy of science, but it can also develop into an important area for practical inference applications. Other pdf readers should be adjusted such that returning to the previous page is as a handy shortcut available. We introduce a novel approach based on speckle pattern. Tracking multiple objects outside the line of sight using. We have demonstrated that even though speckle patterns from different objects are very similar, they contain minute dissimilarities that can be used to differentiate between the originating scatterers.
Optical speckle patterns were first observed in the early 1960s when laser light was reflected from rough surfaces and have since been studied. Free knitbits enewsletter by norah gaughan and cirilia rose. Therefore, the chosen speckle pattern is firstly transformed into a black and white image. The images of the three speckle patterns are numerically deformed as to simulate a heterogeneous or a homogeneous deformation. The generation of a random intensity distribution, called a speckle pattern, when light from a highly coherent source, such as a laser, is scattered by a rough surface or.
Analysis of speckle patterns for deformation measurements. An important remark must be taken into consideration during the recording of speckle data which states that the speckle size must be greater. It is now well recognized that the accuracy and precision in dic measurements not only rely on correlation algorithms, but also. Light scattering due to interaction with a material has long been known to create speckle patterns. Osa specklelearningbased object recognition through. Speckle patterns of handwritten digits from simulation. Our experiments demonstrate that twophoton speckle from a surface scatterer and a volume scatterer look entirely different.
Electronic speckle pattern interferometry espi espi on the other hand, records the surface displacement of an object in response to the applied force. Allfiber spectrometer based on speckle pattern reconstruction. Plenty of new applications are rising, and consequently pattern analysis and synthesis turn into significant subfields in pattern recognition. Information processing using speckle patterns springerlink.
Pdf pattern recognition and machine learning download. They have been used in a variety of applications in microscopy, imaging, and optical manipulation speckle patterns typically occur in diffuse. Selection of suitable feature descriptors is an important but difficult manual task. Using an optimal speckle pattern is one of the most important factors in reducing measurement noise and improving overall results. Line and boundary detection in speckle images image. Direct object recognition without lineofsight using optical.
An example of such a speckle size distribution curve is shown in fig. Analysis of laser speckle severity, granularity, and anisotropy using the power spectral density in polarcoordinate representation desmond c. Pattern recognition is persistent to be one of the imperative research fields in computer science and electrical engineering. Projection of speckle patterns for 3d sensing view the table of contents for this issue, or go to the journal homepage for more 2008 j. Recognition of direction of new apertures from the. These techniques can dramatically increase the resolution of groundbased telescopes, but. In this report recognition of five out of ten paper samples is presented. Choose from over a million free vectors, clipart graphics, vector art images, design templates, and illustrations created by artists worldwide. Recognition of paper samples by correlation of their. We present an adversarial deep learning framework for laser speckle reduction, called deeplsr, that transforms images from a source. Speckle pattern processing by digital image correlation core.
This enables tracking of a single, rigidly moving nlos object using existing specklebased motion estimation techniques. Free berroco design studio blog by norah gaughan and cirilia rose. Early recognition of apical ballooning syndrome by global longitudinal strain using speckle tracking imagingthe evil eye pattern, a case series sualy sosa m. Opties and lasers in engineering 23 1995 1216 eisevier science limited printed in northern ireland elsevier 0143816695000100 optical processing of speckle images with bacteriorhodopsin for pattern recognition john d. Analysis of laser speckle severity, granularity, and. Citescore values are based on citation counts in a given year e. This pattern results from the interference of multiple coherent spherical waves, emitted by point sources forming the objects surface in the case of reflection or the medium in the case of transmission 1. Although this phenomenon has been investigated by scientists since the time of newton, speckles have come into prominence since the invention of the laser. This model represents knowledge about the problem domain prior knowledge. Electronic speckle pattern interferometry espi non. Direct object recognition without lineofsight using. The two orthogonally polarized speckle patterns are independent and an automatic 2 reduction will result1,2. Quality assessment of speckle patterns for digital image.
A very simple and useful pdf reader for this document issumatra pdf. A speck or small spot, as a natural dot of color on skin, plumage, or foliage. A key challenge we address is that speckle imaging is very sensitive to the location of the camera, so removing and reintroducing the camera requires highaccuracy viewpoint alignment. We present an optical method for detection of inplane movement of a diffusing object. Speckle pattern article about speckle pattern by the. A new hybrid algorithm for speckle noise reduction of. To this end, we use a combination of computational rephotography and correlation analysis of the speckle pattern as a function of camera translation. Pdf statistical properties of laser speckle patterns researchgate. In this way speckle pattern a is created, featuring the small speckles. They can be divided into the shiftandadd image stacking method and the speckle interferometry methods. Ong sanjeev solanki xinan liang xuewu xu data storage institute astar agency for science, technology and research singapore 117608, singapore email.
We used the support vector machine for binary classification of the captured speckle. Projection of speckle patterns for 3d sensing iopscience. However, when imaging multiple nlos objects, the speckle components due to different objects are superimposed on the virtual bare sensor image, and cannot be analyzed separately for recovering the motion of individual objects. If a is the surface of a lens or another intermediate surface of the imaging system, the speckle pattern is known as subjective. The images in the top row are original images of handwritten dig. Rss feed, knitting trends, yarn shops, pattern corrections. It is often needed for browsing through this ebook. Encyclopedia of laser physics and technology speckle. Digital speckle pattern interferometry and related techniques. Speckle imaging describes a range of highresolution astronomical imaging techniques based on the analysis of large numbers of short exposures that freeze the variation of atmospheric turbulence. The speckle patterns can be made by multimode fibers or ground glasses. However, it has been during the last 15 years that espi, boosted by the availability of affordable and increasingly powerful digital image processing systems, has grown into one of the leading optical measurement techniques, receiving new names such as tv.
Here, combining the compressive sensing with feature extraction, a method of efficient speckle based compressive target recognition through scattering media is proposed. A related technique has been in use in pattern recognition by lee and rhodes 1821 and by hou and bamberger 22, 23. Speckle contrast reduction in laser projection displays. Therefore, the speckle pattern ir contains information of the object, and an appropriate deep learning network can effectively use such information to perform object recognition.
If a is the reflective surface of an object, the speckle pattern is known as objective. Our experiments demonstrate that twophoton speckle from a surface scatterer and a. The technique is based on spatial filtering of the laser speckle pattern. Pdf improvement to largecapacity pattern recognition.
The morphological technique yields the best results for binary images. However, the major challenge was found with the mixed patterns. In general, a speckle parameter such as mean speckle size. Pdf when laser light strikes a diffuse object, such as paper, the scattered light has been observed to possess a granular spatial structure. Digital holography dh is usually free of misinterpretation, but when an expression like imageplane digital. Speckle pattern is a random granular pattern produced by the reflection of coherent light beam e. Pdf recognition of paper samples by correlation of their. By use of speckle modulation on the object beam of a volume holographic optical correlation system, we show that the sidelobes of the correlation patterns along the vertical direction, as well as. Laser speckle photography surface tampering detection.
A record of the speckle pattern on a high resolution photographic plate acts as an ordinary diffuser and most of the applications are derived from the. In the experiments, speckle intensity images of amplitude or phase objects on a spatial light modulator between scattering plates were captured by a camera. It is possible to realize nonlineofsight nlos recognition with these speckle patterns. In the case of speckle pattern a the most frequent radii lie between 0 and 3 pixels, and for speckle pattern c between 3 and 7. Electronic speckle pattern interferometry espi use tv system to record speckle instead of film gives realtime measurements minimum speckle size limited by camera resolution can perform computer analysis of speckle data optics 505 james c. Conventional target recognition through scattering media is composed of two steps, i. Berroco handknitting yarns are used to knit or crochet fashion sweaters, shawls, wraps, scarves, hats, coats, children and baby garments, throws and afghans. The intensity pattern at plane b is a speckle pattern. The speckle patterns recorded before and after displacement of the surface are needed to carry out the analysis. The wavelength is written on the top and also marked by the red line in the bottom scale.
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