We have constructed a new speckle imaging system that collects a large number of speckle patterns on the detector area of a large-format CCD. The system is called the RIT-Yale Tip-tilt Speckle Imager (RYTSI) because it uses two galvanometric scanning mirrors to tip and tilt each speckle pattern to a different location on the CCD chip. It therefore solves the bandwidth problem of using CCDs in s...

The digital image correlation (DIC) technique is successfully applied across multiple length scales through the generation of a suitable speckle pattern at each size scale. For microscale measurements, a random speckle pattern of paint is created with a fine point airbrush. Nanoscale displacement resolution is achieved with a speckle pattern formed by solution deposition of fluorescent silica n...

Live imaging of normal and abnormal vascular development in mammalian embryos is important tool in embryonic research, which can potentially contribute to understanding, prevention and treatment of cardiovascular birth defects. Here, we used speckle variance analysis of swept source optical coherence tomography (OCT) data sets acquired from live mouse embryos to reconstruct the 3-D structure of...

This paper presents the methods used to adapt the geometric filtering method for speckle reduction to ultrasound imaging The geometric filtering method is an iterative algorithm for speckle reduction which was first applied to radar images obtained with well controlled axial and lateral resolution. The appearance of speckle in ultrasound images is directly related to the size of the point-sprea...

Medical images are often deteriorated by noise due to various sources of interferences and other phenomena that affect the measurement processes in an imaging and acquisition system. Speckle noise is a random mottling of the image with bright and dark spots, which obscures fine details and degrades the detectability of low-contrast lesions. Speckle noise occurrence is often undesirable, since i...

Biomedical images are generally corrupted by speckle noise and Gaussian noise. Speckle noise is multiplicative type whereas other noises like Gaussian noise are additive type. It is difficult to remove multiplicative noise from images. We have presented various techniques for removing speckle noise from images and image enhancement by thresholding using various spatial domain filters and Wavele...

We study the noise of the intensity variance and of the intensity correlation and structure functions measured in light scattering from a random medium in the case when these quantities are obtained by averaging over a finite number N of pixels of a digital camera. We show that the noise scales as 1/N in all cases and that it is sensitive to correlations of signals corresponding to adjacent pix...

This work presents, to our knowledge, the first demonstration of the Laser Speckle Contrast Imaging (LSCI) technique with extended depth of field (DOF). We employ wavefront coding on the detected beam to gain quantitative information on flow speeds through a DOF extended two-fold compared to the traditional system. We characterize the system in-vitro using controlled microfluidic experiments, a...

Speckle filtering and detail preservation are two key issues in speckle suppression of Synthetic Aperture Radar (SAR) imagery. Different applications may require different balances between speckle reduction and detail retention. This paper presents a detail-preserving and flexible filter. Both quantitative and qualitative criteria, including speckle reduction, edge retention, texture preservati...