690 results about "Speckle noise" patented technology

A displaying optical system is disclosed, which is capable of reducing a speckle noise. The displaying optical system comprises a light source emitting coherent light, a scanning device scanning the light, a first optical system causing the light from the scanning device to form an intermediate image, a second optical system causing the light from the intermediate image to form an image on a real display surface, and an optical element arranged between the first and second optical systems. The optical element widens the divergence angle of the light emerged from the optical element toward the second optical system more than the incident angle of the light on the optical element from the first optical system.

An object of the invention is to provide a laser illuminating device and an image display device that enable to remove speckle noises in a diffraction field and an image field, uniformly illuminate an illumination plane, and realize miniaturization. A laser illuminating device 100 includes a laser light source 3, a first lens 1 including a plurality of microlenses 10 each having a predetermined numerical aperture in an in-plane direction, each of the microlenses 10 being adapted to expand laser light emitted from the laser light source 3 to thereby superimpose the laser light transmitted through each of the microlenses 10; and a second lens 2 having an effective diameter larger than an effective diameter of the first lens 1, and for compensating for a divergence angle of the laser light expanded by each of the plurality of the microlenses 10.

A 2-dimensional beam scan unit (2) reflects emission beams from a red laser light source (1a), a green laser light source (1b) and a blue laser light source (1c) and scans in a 2-dimensional direction. Diffusion plates (3a, 3b, 3c) diffuse the respective light beams scanned in the 2-dimensional direction to introduce them to corresponding spatial light modulation elements (5a, 5b, 5c). The respective spatial light modulation elements (5a, 5b, 5c) modulate the respective lights in accordance with video signals of the respective colors. A dichroic prism (6) multiplexes the lights of the three colors after the modulation and introduces the multiplexed lights to a projection lens (7) so that a color image is displayed on a screen (8). Since the 2-dimensional light emitted from the beam scan unit is diffused to illuminate the spatial light modulation element, it is possible to change the optical axis of the beam emerging from the light diffusion member for irradiating the spatial light modulation element moment by moment, thereby effectively suppressing speckle noise.

Methods of and systems for illuminating objects using planar laser illumination beams having substantially-planar spatial distribution characteristics that extend through the field of view (FOV) of image formation and detection modules employed in such systems. Each planar laser illumination beam is produced from a planar laser illumination beam array (PLIA) comprising an plurality of planar laser illumination modules (PLIMs). Each PLIM comprises a visible laser diode (VLD, a focusing lens, and a cylindrical optical element arranged therewith. The individual planar laser illumination beam components produced from each PLIM are optically combined to produce a composite substantially planar laser illumination beam having substantially uniform power density characteristics over the entire spatial extend thereof and thus the working range of the system. Preferably, each planar laser illumination beam component is focused so that the minimum beam width thereof occurs at a point or plane which is the farthest or maximum object distance at which the system is designed to acquire images, thereby compensating for decreases in the power density of the incident planar laser illumination beam due to the fact that the width of the planar laser illumination beam increases in length for increasing object distances away from the imaging optics. Advanced high-resolution wavefront control methods and devices are disclosed for use with the PLIIM-based systems in order to reduce the power of speckle-noise patterns observed at the image detections thereof. By virtue of the present invention, it is now possible to use both VLDs and high-speed CCD-type image detectors in conveyor, hand-held and hold-under type imaging applications alike, enjoying the advantages and benefits that each such technology has to offer, while avoiding the shortcomings and drawbacks hitherto associated therewith.

For a lighting device for obtaining output light in the wavelengths of light of three colors of red, green, and blue, a lighting device using a semiconductor laser for the blue light has been proposed. When using this lighting device in an image display device, etc., there are problems in blue color rendering properties and reduced image quality due to speckle noise. A light source device designed to emit red light, green light, a first blue light, and a second blue light, the light source device including: a red solid-state light source; a green solid-state light source; a semiconductor laser for emitting the first blue light; and a blue light generation part for emitting the second blue light, wherein the main component of the second blue light is light in a wavelength range of wavelengths longer than that of the first blue light.

An image projector realizing image projection with high image quality by reducing speckle noise. An image projector comprising a coherent light source, a collimation lens for transforming coherent light emitted from the coherent light source into coherent parallel light, and a projection optical system for projecting coherent parallel light is further provided with a reflection element for reflecting the coherent parallel light and capable of oscillating in parallel with the direction normal to the reflection plane, and a reflection element drive means for causing oscillatory motion of the reflection element.

The invention belongs to the field of treatment of medical images, and relates to a breast neoplasms ultrasonic image segmentation method based on improved level set algorithm. The method is characterized in that the original image is pre-treated and remains the effective area, the speckle noise is removed, so as to achieve the purpose of protecting the boundary; the image is adaptively segmented according to the threshold. The method comprises the steps of (1) inversing color for the image; (2) determining the threshold; (3) screening candidate areas; (4) arranging the rest candidate areas; (5) determining seed points. With the adoption of the method, the seed points can be quickly found, the seed points can be kept in a neoplasms area, and the accurate determination of the seed points ensures the accuracy of area growth and level set; in addition, the seed points grow in the area, and the initial contour can be found; the classic Chan-Vese (CV) algorithm is improved; the global statistics information of the curved line of the contour in the development process is considered during calculating the global statistics information; the accuracy of the segmentation result is ensured, and moreover, the automation level of the segmentation method can be further improved.

A pattern defect inspection apparatus capable of detecting minute defects on a sample with high sensitivity without generating speckle noise in signals is realized. Substantially the same region on a surface of a wafer is detected by using two detectors at mutually different timings. Output signals from the two detectors are summed and averaged to eliminate noise. Since a large number of rays of illumination light are not simultaneously irradiated to the same region on the wafer, a pattern defect inspection apparatus capable of suppressing noise resulting from interference of a large number of rays, eliminating noise owing to other causes and detecting with high sensitivity minute defects on the sample without the occurrence of speckle noise in the signal can be accomplished.

The present invention provides a surface illuminator having a uniform luminance over a large area by using a laser light source, having a wide color reproduction range, and capable of suppressing a speckle noise, as well as a liquid crystal display using the same. The surface illuminator of the present invention includes the laser light source that emits a laser beam; a beam scan section that deflects and scans the laser beam; and a first plate-shaped light guide that makes the laser beam deflected and scanned by the beam scan section to be incident from an end face portion and making the incident laser beam to emit from a first major surface. Further, the liquid crystal display of the present invention includes a liquid crystal display panel and the surface illuminator, wherein the surface illuminator is used as a backlight illuminator that lights the liquid crystal display panel from backside in this liquid crystal display.

A system and method for tracking an airborne target including an illumination source (e.g., a diode laser array) is used to enhance a target signature and a detector (e.g., a passive high-speed camera) is used to detect to electromagnetic radiation (e.g., infrared radiation) reflected off the target. The received electromagnetic radiation may be processed by a digital computer and passed through a spatial filter that implements a band limited edge detection operation in the frequency domain. The filter may remove low spatial frequencies that attenuate soft edged clutter such as clouds and smoke as well as filter out artifacts and attenuated medium to high spatial frequencies to inhibit speckle noise from the detector as well as speckle from the laser return off the target.

A laser light source is provided with a pump light source (1) comprising a semiconductor laser, a solid laser medium (2) which is excited by the semiconductor laser, and multi-mode means for changing at least either a longitudinal mode or a transverse mode of laser oscillation of the solid laser. The oscillation light of the laser medium excited by the light outputted from the pump light source is changed by the multi-mode means into output light (5) having a plurality of oscillation spectra and is outputted, thereby a small, high power, and highly efficient low coherent light source can be realized, and a laser light source having reduced speckle noises can be provided.

In a two-dimensional image display device, speckle noise is reduced by a simple construction. A two-dimensional image display device for displaying an image by projecting coherent light onto a projection plane is provided with at least one coherent light source (1a), (1b), (1c) for outputting coherent light, a polarization state modulator 6 for modulating at least one of a polarization state and a phase of the coherent light emitted from the coherent light source, and a birefringent diffusion plate 7 for spatially varying the phase of the coherent light emitted from the polarization state modulator, wherein the polarization states of light spots in the respective pixels of the image displayed on the projection plane are spatially and temporally varied, thereby forming various speckle patterns.

A compact displaying optical system capable of reducing a speckle noise and a loss of light amount is disclosed. The displaying optical system which projects images using coherent light, comprises a light source which emits the light; and a polarization control unit. The polarization control unit changes the polarization state of the light emitted from the light source temporally.

The invention relates to an SAR image denoising method based on a multi-scale hole residual attention network. The method comprises the following steps of by extracting features of different scales ofthe image through a multi-scale convolution group, broadening a convolution kernel receptive field by utilizing cavity convolution; exuecting more context information of the image; and transmitting the feature information of the shallow layer to a deep convolutional layer by using jump connection to keep image details, adding an attention mechanism to intensively extract noise-related features, and automatically learning the SAR image speckle noise distribution form in combination with a residual error learning strategy to achieve the purpose of removing speckle noise. Experimental results show that compared with a traditional SAR image noise removal method, the method has the advantages that the speckle noise removal effect is good, the number of artificial traces is small, detail information of the image is kept, and the calculation speed is higher through the GPU.

A light diffuser containing light diffusing elements is arranged in the most appropriate position between a spatial light modulator and an illumination optical system. Thereby, particles as light diffusing elements diffuse rays of light emitted from a laser light source. Accordingly, indefinite numbers of speckle pattern are formed so that, for example, a speckle noise which occurs on an image projected to a screen is reduced. As a result, loss of light amount after light diffusion is suppressed to small amount, and thereby a laser image display apparatus capable of displaying a bright and high-quality image having no luminosity irregularity is provided.

The invention discloses a polarized SAR image classification method based on a nonsubsampled contourlet convolutional neural network, and mainly at solving the problems that influence of speckle noises is hard to avoid and the classification precision is low in the prior art. The method comprises the steps that a polarized SAR image to be classified is denoised; Pauli decomposition is carried out on a polarized scattering matrix S obtained by denoising; image characteristics obtained via Pauli decomposition are combined into a characteristic matrix F, and the characteristic matrix F is normalized and recorded as F1; 22*22 blocks surrounding the F1 are taken for each pixel point to obtain a block based characteristic matrix F2; a training data set and a test data set are selected from the F2; the nonsubsampled contourlet convolutional neural network is established to train the training data set; and the trained nonsubsampled contourlet convolutional neural network is used to classify the test data set. The polarized SAR image classification method improves the expression capability and the classification precision of the features of the polarized SAR image, and can be used for target identification.

This invention relates to one two-dimension fuzzy poly spot noise filter and brightness compensation B type of hypersonic cutting method, which comprises the following steps: extending the image brightness information to the update two-dimension poly fuzzy type near the pixel zone based on image brightness information; leading each heter diffusion spot noise filter to the fuzzy poly aim function to provide near information and to strengthening spot robust property; leading two-dimension fuzzy poly aim function with brightness compensation factor based on the noisy on uneven hypothesis and using image aim and background even to strengthen uneven noise robust.

An illumination light source is provided with a laser light source having a laser medium with a specified gain region, and a reflector having a narrow band reflection characteristic. A part of a laser light emitted from the laser light source is reflected and fed back by the reflector, so that an oscillation wavelength of the laser light source is fixed at a reflection wavelength. A peak of the gain region of the laser medium is shifted from the reflection wavelength by a change of an oscillation characteristic of the laser light source, so that the oscillation wavelength of the laser light source is changed from the reflection wavelength. Thus, an oscillation spectrum of the laser light source is spread to reduce speckle noise.

The invention discloses an SAR image nonlocal mean value speckle filtering method which belongs to the technical field of image processing, and mainly overcomes the problem of inaccurate distance computation of traditional SAR image nonlocal mean value speckle filtering similar blocks. The method comprises the following realization processes: 1. firstly judging whether a pixel point of an input SAR image is a point target, if so, keeping the gray value of the point target, otherwise performing the next step; 2. computing the distance between the pixel point and all pixel points in a search field according to a new distance measurement; 3. computing the weight values of all the pixel points in the search field according to the computed distance of all the pixel points in the search field; 4. carrying out weighted averaging for all the pixel points in the search field according to the computed weight values of all the pixel points in the search field to obtain the modified gray value of the pixel point; and 5. replacing the gray value of all points in the original SAR image with the modified gray value to obtain the speckle filtered SAR image. Compared with some traditional and classical speckle filtering methods, the invention can better smooth speckle noise and simultaneously keep the edge and texture details of the SAR image.

A process and system for automating the image quality inspection and correction for scanned document which previously required a human operator. For every scanned and thresholded image, the process and system performs an automatic evaluation through a binary image quality detection system which generates an image noise index indicative of the amount of image artifacts or image loss. When a poor quality scanned page is detected, for example, too much speckle noise, the gray scale image is retrieved or the image is rescanned. The gray scale image then automatically undergoes an image quality correction process to produce a clean, readable binary image.

The invention discloses an all-solid digital holography imaging system capable of reducing speckle noise, and belongs to the technical field of optical diffraction imaging and digital holography. The all-solid digital holography imaging system capable of reducing the speckle noise comprises a hologram shooting light path, a spatial light modulator, a sample to be detected, an image sensor and a computer. The reference light in the hologram shooting light path is directly incident to the image sensor, the object light in the hologram shooting light path passes through the spatial light modulator and the sample to be detected and then is incident to the image sensor, both the image sensor and the spatial light modulator are connected with the computer, under the control of different phase information provided by the computer, the spatial light modulator is loaded with different random phase mask plates, every time a random phase mask plate is loaded, the image sensor is controlled to record a hologram for one time, multiple holograms are continuously and automatically obtained, and all reproductive images of the holograms are overlapped. The speckle noise of the reproductive images of the digital holography imaging system can be automatically reduced, and the all-solid digital holography imaging system capable of reducing the speckle noise can be used for imaging detection which is relatively high in requirements for instantaneity and distinguishability.

Red, green, and blue laser light emitted from laser light sources 1-3 is transformed into substantially parallel beams by collimator lenses 4-6, collected by microlens arrays 7-9, and rendered uniform by rod integrators 10-12, whereupon it is used to illuminate spatial light modulation elements 16-18 and subjected to modulation. The modulated laser light exiting from the spatial light modulation elements 16-18 is recombined using a beam-combining prism 19 and subjected to pixel separation using a birefringent plate 20, which is rotationally driven by a birefringent plate rotary drive unit 26, after which it is projected upon a screen 22 using a projection optical system 21. The birefringent plate 20 spatially separates the modulated laser light using birefringence. When pixels are spatially separated by the birefringent plate, the pixel grid region is made smaller, the distribution of brightness on the screen is rendered uniform, and speckle noise is reduced.

The invention discloses a double-frequency coherent wind lidar based on single-frequency continuous light EOM modulation. The double-frequency coherent wind lidar adopts dual-wavelength laser as a light source, and detects difference of dual-wavelength Doppler frequency shifts through coherent beat frequency to invert speed; and meanwhile, Doppler frequency shift information is extracted by adopting a microwave signal, thereby reducing speckle noise due to detection object unevenness and atmosphere turbulence. Besides, two side frequencies are generated through a single-frequency continuous wave EOM modulation method; double-frequency laser is generated through a method of utilizing a filter to filter center light frequency and filter out the two side frequencies; and the double-frequency laser generation method improves stability of a double-frequency gap, and the double-frequency gap can be controlled flexibly by adjusting trigger signals of modulators. According to the scheme, the dual-wavelength laser is obtained through single-frequency continuous wave EOM modulation, the speed is extracted through a microwave mode, and atmosphere wind speed information is inverted; the stability of the double-frequency gap is improved; and the double-frequency coherent wind lidar has the advantages of high detection precision, anti-electromagnetic interference and compact structure and the like.

A laser projector is provided with a laser light source (1); a two-dimensional light modulator (6) which modulates light from the laser light source (1); and a projection optical system (7) which projects images onto a display plane (10) by expanding the light modulated by the two-dimensional light modulator 6). Shift of a display position of the two-dimensional light modulation element (6) and shift of the projection optical system (7) are performed in synchronization with each other so that display positions of the images on the display plane (10) are made substantially identical to each other. Thereby, speckle noise is sufficiently removed, and high-grade images are displayed.