130 results about "Speckle contrast" patented technology

An optical system (100) comprises a coherent light source (101) and optical elements for directing light from the source to a target (1001). The optical elements include at least one diffusing element (141, 161) arranged to reduce a coherence volume of light from the source and a variable optical property element (151). A control system (1021) controls the variable optical property element such that different speckle patterns are formed over time at the target (1001) with a temporal frequency greater than a temporal resolution of an illumination sensor or an eye (1011) of an observer so that speckle contrast ratio in the observed illumination is reduced. The variable optical property element (151) may be a deformable mirror with a vibrating thin plate or film.

Provided are a laser speckle contrast imaging method, a laser speckle contrast imaging system, and an apparatus which includes the laser speckle contrast imaging system. The laser speckle contrast imaging system includes a laser light source configured to irradiate laser beams toward a subject, the laser beams having a plurality of wavelength bands and different surface transmittances with respect to the subject. An imaging unit is configured to acquire speckle images by capturing images of speckles by using an image sensor, the speckles being formed when the irradiated laser beams are scattered from the subject. A signal processor is configured to convert the acquired speckle images into speckle contrast images and to acquire a compensated speckle contrast image by compensating for a change caused by a movement of the subject.

A selectable high dynamic laser speckle blood flow imaging device and method include a laser source, a sample fixing table, a beam expander, a half-mirror, a first CCD camera, a second CCD camera anda stepping motor. Continuous acquisition of original speckle images using multi-exposure acquisition is carried out, which solves the shortcoming of the traditional laser speckle contrast imaging method that the original speckle image is captured by a fixed exposure time. In addition, the present invention provides a dual imaging system. The whole body blood flow image is obtained by the focusingsystem, the local area is enlarged by the zoom system to obtain the angiographic image with more blood vessel information, and the images obtained by the two optical systems are fused to obtain the angiographic image with higher imaging resolution. It will be of great significance in the fields of early diagnosis of diseases, disease analysis and dynamic monitoring of drug efficacy in vivo.

A method of operating a laser source comprising is provided. The method reduces speckle contrast in a projected image by creating a plurality of statistically independent speckle patterns. The method comprises generating a plurality of sub-beams that define an optical mode. The method further comprises controlling the phase of selected sub-beams to continuously sequence the laser source through a plurality of orthogonal optical modes. The plurality of orthogonal modes create a corresponding number of statistically independent speckle patterns, thus reducing speckle contrast in a image projected using the laser source by time averaging.

A non-invasive method for measuring blood flow in principal vessels of a heart of a subject is provided. The method includes illuminating a region of interest in the heart with a coherent light source, wherein the coherent light source has a wavelength of from about 600 nm to about 1100 nm; sequentially acquiring at least two speckle images of the region of interest in the heart during a fixed time period, wherein sequentially acquiring the at least two speckle images comprises acquiring the at least two speckle images in synchronization with motion of the heart of the subject; and electronically processing the at least two acquired speckle images based on the temporal variation of the pixel intensities in the at least two acquired speckle images to generate a laser speckle contrast imaging (LSCI) image and determine spatial distribution of blood flow rate in the principal vessels and quantify perfusion distribution in tissue in the region of interest in the heart from the LSCI image.

Blood flow rates can be calculated using diffuse speckle contrast analysis in spatial and time domains. In the spatial domain analysis, a multi-pixel image sensor can be used to detect a spatial distribution of speckles in a sample caused by diffusion of light from a coherent light source that is blurred due to the movement of scatterers within the sample (e.g., red blood cells moving within a tissue sample). Statistical analysis of the spatial distribution can be used to calculate blood flow. In the time domain analysis, a slow counter can be used to obtain time-series fluctuations in light intensity in a sample caused by diffusion of light in the sample that is smoothened due to the movement of scatterers. Statistical analysis of the time-series data can be used to calculate blood flow.

A projector includes a light source module, a diffuser for diffusing the light beam emitting from the light source module, and a fluorescent plate. The light source module includes a light source capable of emitting a first light beam, a dichroic device for diverging the first light beam into a second light beam and a third light beam, and a reflector with a moving frequency exceeding 20 Hz configured for reflecting the third light beam. The fluorescent plate is configured for converting the light beam passing through the diffuser into at least three kinds colored light beams.

The invention relates to a laguerre-gaussian beam-based speckle contrast imaging measurement device and a laguerre-gaussian beam-based speckle contrast imaging measurement method. The device comprises a continuous wave laser; after being reflected by a total reflective mirror, a light beam emitted by the continuous wave laser irradiates on a collimating beam expander; after that, the light beam becomes linearly polarized light by a polarizer and then irradiates on a beam splitting prism; after passing through the beam splitting prism, the light beam is divided into two beams, wherein one path is reflected light, and the other path is transmission light; the reflected light beam irradiates on a spatial light modulator, and the light beam reflected by the spatial light modulator irradiates on a diaphragm after passing through the beam splitting prism and an analyzer again; after passing through the diaphragm, the light beam irradiates on a sample to be tested; after being scattered by the sample to be tested, the light beam is converged by an imaging lens, and then an image is formed in a charge coupled device (CCD) camera; after that, the image is stored in a computer, and the image contrast value can be calculated; when a light path is difficult to adjust, the speckle size is adjusted by changing the characteristics of the illumination beam, so that the method has the characteristics of being flexible and reliable; the method is widely applied to the fields such as hemorheology monitoring, plant growth condition monitoring, etc.

The invention discloses a multi-mode imaging system for observing cerebral cortex functions of moving animals, comprising a light source device, an image transferring optical fiber, a light transferring optical fiber, a spectroscope, an intrinsic signal imaging part, a laser speckle contrast imaging part, a fluorescence Imaging part, an animal activity room, an image acquisition card, a computer, wherein the light source device generates three light sources needed by an imaging mode, the image transferring optical fiber is used for transferring the cerebral cortex images to a spectroscope when the animals moves around freely; the light transferring optical fiber transfers the light of the light source to the cerebral cortex of the aminals; the spectroscope divides imaging light beam transferred by the image transferring optical fiber into three beams and carries out intrinsic signal imaging, laser speckle contrast imaging and fluorescence Imaging; the intrinsic signal imaging part is used for the intrinsic signal imaging; the laser speckle contrast imaging part for laser speckle contrast imaging; the fluorescence Imaging part is used for fluorescence Imaging; the animal activity room is used for the experiment animals to move freely; the image acquisition card is used for image acquisition and the computer for system control and image receiving and processing.In the invention, optical fiber light and image transferring can be used to multi-mode imaging when the animals are conscious and active and the invention comprises intrinsic signal imaging, laser speckle contrast imaging and fluorescence Imaging.

An embodiment in accordance with the present invention provides a system and method for imaging living tissue and processing laser speckle data anisotropically to calculate laser speckle contrast preferentially along the direction of blood flow. In the present invention, raw laser speckle images are obtained and processed resulting in the anisotropic laser speckle images. The system and method involve the determination of the direction of blood flow for every pixel within the region of interest (primary pixel) and subsequent extraction of a set of secondary pixels in the spatio-temporal neighborhood of the primary pixel that is anisotropic in the direction of blood flow. Speckle contrast is then calculated for every primary pixel as the ratio of standard deviation and mean of all secondary pixels in this anisotropic neighborhood and collectively plotted using a suitable color mapping scheme to obtain an anisotropic laser speckle contrast image of the region of interest.

An image projector having one or more broadband lasers designed to reduce the appearance of speckle in the projected image via wavelength diversification. In one embodiment, a broadband laser has an active optical element and a nonlinear optical element, both located inside a laser cavity. The broadband laser generates an output spectrum characterized by a spectral spread of about 10 nm and having a plurality of spectral lines corresponding to different spatial modes of the cavity. Different individual spectral lines effectively produce independent speckle configurations, which become intensity-superimposed in the projected image, thereby causing a corresponding speckle-contrast reduction.

The invention discloses a phase modulator performance parameter testing device based on beam coherent combination. The phase modulator performance parameter testing device comprises a laser (1), a 1*2 optical beam splitter (2), a first optical fiber, a second optical fiber, a third optical fiber and a fourth optical fiber, a phase modular (4), a first optical collimator, a second optical collimator, a beam combining lens (6), a beam splitter prism (7), a first microobjective, a second microobjective, a digital camera (9), a pinhole (10), a photoelectric detector (11), a frequency response tester (12) and a computer (13). The phase modulator performance parameter testing device simplifies measurement of phase modulator performance parameters and can measure all phase modulators with optical fiber interfaces. Simultaneously, the device can roughly estimate and accurately measure resonant frequency. When accuracy requirements are not high, the digital camera is used for observing far field speckle contrast to obtain the resonant frequency simply and rapidly; and when the accuracy requirements are high, accurate resonant frequency is obtained through analysis and calculation of signals acquired by the photoelectric detector.

The invention relates to a speckle measuring and evaluating method in laser projection display. A power spectrum density function of a speckle pattern is utilized to evaluate the effect of speckle elimination, and the method comprises the steps that: three one-dimensional physical quantities which are respectively a radial power spectrum density rPSD, an angle power spectrum density aPSD and a total power spectrum density tPSD are defined for the speckle pattern to be measured and evaluated, wherein the three one-dimensional physical quantities respectively reflect speckle granularity, anisotropy and speckle severity in the pattern; and the calculated values of the above three physical quantities are analyzed to provide a speckle measuring and evaluating result. Compared with speckle contrast, the method can analyze the speckle pattern more comprehensive, the speckle severity in the pattern is evaluated, the speckle granularity is measured, and the differences of different speckle elimination methods in speckle elimination in all directions are evaluated. The invention has a great significance on the comparison of different speckle elimination methods and the application of a laser projection display technology.

A speckle contrast reducing method for a laser scanning projection system includes the following steps. Firstly, a laser beam is provided. The laser beam is projected on a projection surface according to a first scanning trajectory, thereby generating a first image frame. Sequentially, the laser beam is projected on the projection surface according to a second scanning trajectory, thereby generating a second image frame at an image refresh rate. Moreover, the second scanning trajectory of the second image frame is shifted by a displacement from the first scanning trajectory of the first image frame along a slow-axis direction.