162 results about "Underwater imaging" patented technology

Provided is a method of carrying out an underwater video survey of a scene, the method operating in an underwater imaging system comprising a first camera module, a second camera module and a lighting module to provide a plurality of illumination profiles, wherein the method comprises repeating the following steps at a desired frame rate: the first camera module capturing a first image of the scene, where the scene is illuminated according to a first illumination profile; and the second camera module capturing a second image of the scene, where the scene is illuminated according to a second illumination profile; characterised in that the first camera module is a HD colour camera module and the first illumination profile provides white light suitable for capturing a HD image; and the second camera module is a low light camera module, and the second illumination profile is suitable for use with the low light camera module.

The invention provides an underwater camera calibration method. During the imaging process of an underwater camera system, mathematical modeling is performed for the physical process of underwater imaging according to the sequence for the light: water-water isolating plane-air-camera lens. The difference between the air camera parameter and the underwater camera parameter resides in that because of existence of a refraction plane, the imaging model in the air is not suitable to be in the water so that modeling of the imaging module for the underwater camera is needed. The invention discloses an underwater camera calibration method with high precision for establishing an underwater refraction imaging model, and provides an underwater camera calibration method based on a Tsai calibration algorithm being able to accurately calculate the distance d between the center of the camera and the refraction plane and the internal and external parameters of the camera. The underwater camera calibration method can be widely applied to underwater detection and underwater object measurement with high precision.

The invention provides an underwater measuring method based on vision.The underwater measuring method comprises the steps that firstly, pre-calibration in air is carried out, wherein two cameras are fixed in sealed equipment and shoot multiple plane calibration images, internal parameter matrixes of the two cameras are calibrated respectively, and a basic matrix between the two cameras is calibrated by shooting two images of a plane calibration plate; secondly, underwater cameras are calibrated, wherein underwater three-dimensional calibration plate images are shot, and external parameter matrixes of all the cameras and parameters of distances between the centers of the cameras and a refraction plane are calibrated.The invention discloses an underwater dimension measuring method for achieving precise calibration of the cameras through an established accurate underwater imaging model.Underwater two-dimension measurement and binocular three-dimension measurement are achieved through camera calibration parameters, and it is verified through experiments that the precision of underwater two-dimension measurement and binocular three-dimension measurement ranges from -0.2 mm to +0.2 mm in the method.The technology can be widely applied to underwater accurate measurement and precise detection.

Described are a method and an apparatus for color-corrected underwater imaging. A range to an underwater object to be imaged is determined and control values are selected according to the range. Control values are predetermined for a number of ranges according to an optimization of a color quality factor for each range based on the spectra of the optical sources used for illumination and the wavelength-dependent optical transmission of the water for the range. The optical power of each optical source is controlled according to a respective one of the selected control values. Advantageously, an acquired image requires no color correction as the adaptive illumination compensates for the wavelength-dependent losses in the light propagation path from the optical sources to the object and from the object to the imaging device.

The invention relates to the technical field of range gated imaging, and discloses a picosecond-accuracy narrow-pulse width transistor-transistor logic (TTL) signal acquisition method based on phase shift AND operation. The method comprises the following steps of: dividing each path of TTL pulse triggering signals comprising pulse laser triggering signals and intensified charge coupled device (ICCD) triggering signals in range gating into two paths of time sequence signals with completely identical phase and amplitude by using a multipath generator; delaying one of the divided two paths of signals by adopting a picosecond-accuracy delay line technology to produce a phase shift between the two paths of signals; and then causing the two paths of signals to pass through a logic AND gate for a logic AND operation, thereby compressing a pulse width. By the method, the phase shift between the two paths of signals is accurately controlled to obtain high-accuracy pulse width signals and higher pulse width compression accuracy, and the compressed pulse width can be close to the limit of the TTL signal, namely the order of magnitude of 1ns; and the method is applied in the field of gating application such as range gated three-dimensional imaging, underwater imaging and the like with high-accuracy time sequence requirements.

The invention discloses a visual water quality information monitoring system based on the Internet of Things and a big data technology. The system comprises a server part, a device layer and a communication layer, and the server layer is a PC terminal and is composed of a plurality of servers; the device layer comprises a water quality monitoring sensor, an underwater imaging system, an underwater unmanned aerial vehicle, an unmanned ship, a Big Dipper / GPS positioning device, a solar battery and a power supply management module; the communication layer is composed of wireless communication devices; and the servers respectively realize fixed water quality monitoring and dynamic water quality monitoring. The system can realize the all-weather remote three-dimensional automatic monitoring of the monitored water quality, can completely record the dynamic change process and the visual display of the water quality data of every monitoring point, provides analysis data, and provides a basis for decision makers. The system can preserve and analyze a large number of water quality data, and can be effectively used in the fields of marine environmental monitoring, pollution monitoring and tracing, and aquaculture detection.

An underwater positioning system provides position information for a rover, moveable within a reference frame. The system may comprise: at least one beacon having a light source, located at a fixed position within the reference frame; an underwater imaging device, moveable with the rover in the reference frame to observe the light source from different viewpoints and determine direction data representing a direction or change in direction of the light source with respect to the imaging device; an orientation sensor, associated with the imaging device to determine an orientation of the imaging device with respect to the reference frame and generate orientation data; and a scaling element for providing scaling data representative of a distance between the imaging device and the light source. Various different beacons may be provided.In alternative system implementations, the locations of light source(s) and underwater imaging device are reversed between rover and beacon(s).

A housing for underwater imaging comprising a first section for housing an optical instrument; a second section secured to the first section adapted to house a window; a window disposed within the second section; and a buffer ring disposed between the window and the first section. The buffer ring is a material having a coefficient of thermal expansion approximately equal to that of the window. In the best mode, the window is optical grade glass and the buffer ring is aluminum foil. In the illustrative embodiment, a mounting ring is disposed between the buffer ring and the second section of the housing. The mounting ring is steel and must be polished, lapped, stainless steel as well. The buffer ring protects the glass window from the mounting ring. A third ring is disposed over the window and secures it to the second section of the housing. The second section is removable relative to the first section to allow for a camera to be placed within the housing and secured thereby for deep-sea underwater use at high pressure.

The invention relates to an underwater imaging device for annular laser lighting, comprising an optical window, an shell, a lighting optical device, a receiving and detecting device and an electronic control module, wherein the light optical device composed of a laser, a beam expander, a front lens, a rear lens and an all-trans lens is arranged in the shell; and the receiving and detecting device is composed of a zoom lens and a camera. The imaging device is characterized by comprising an annular all-trans lens and a beam-transforming device, wherein the annular all-trans lens is arranged in front of the zoom lens, is coaxial with the zoom lens and the camera, and is placed at an angle of 45 degrees; and the beam-transforming device is arranged between the beam expander and the front lens and causes Gaussian beam sent by the laser to be transformed into annular beams. The imaging device of the invention has high imaging quality, can acquire clearer images under the condition of being far away from turbid body of water, is a novel underwater imaging device for underwater detecting operation, and plays an importation role in ocean detection in our country.

The invention discloses an image processing method in an underwater vision SLAM (Simultaneous Localization And Mapping) system. The image processing method comprises the following steps: establishing an underwater imaging model; processing influence of underwater environment factors on a camera imaging; carrying out image feature extraction and matching. According to the method, extraction on feature points of an underwater environment image in the later period is reinforced; according to a data correlation method which is newly disclosed on the basis of the improved SLAM system, the feature points are extracted in a matched manner, so that the feature points can be more rapidly and accurately extracted; real-time performance of an SIFT algorithm is improved. The method which uses a relative position factor of a binocular camera and a way point position factor as auxiliary conditions for carrying out correlation can effectively solve the problems of mismatching and poor matching efficiency in the data correlation.

The invention discloses a method for acquiring and processing three-dimensional image of marine fish, a device, equipment and a medium. The method comprises: acquiring a first two-dimensional image, asecond two dimensional image, a third two-dimensional image and a depth map of a target ocean region by an underwater imaging device, acquiring a parallax map according to the first two-dimensional image and the second two-dimensional image, correcting the depth map according to the third two-dimensional image, obtaining the corrected depth map, based on the parallax map and the corrected depth map, the depth information of each fish being corrected, the corrected depth information of each fish being determined, and the target image including the three-dimensional information of each fish being obtained. According to the target image, the attributes of each fish are determined by depth learning method, which reduces the cost of acquiring the fish swarm distribution information and improves the accuracy of acquiring the fish swarm distribution information.

The invention relates to an underwater active electric field imaging device belonging to the technical field of underwater imaging. The underwater active electric field imaging device comprises a transmitter 1, a receiver 2, a data sampler 3 and a data processor 4, wherein the transmitter comprises a signal generator (1-1) and a transmitting electrode (1-2); and the receiver comprises a receiving electrode (2-1) and a receiving circuit (2-2). The underwater active electric field imaging device has the advantages that: 1, the device carries out imaging through detecting the variation of an electric field so that the problem that the visual field of optical imaging is limited is solved; 2, the device has simple hardware structure and high energy efficiency and can solve the problem of complicated acoustic imaging hardware; and 3, the device can reflect the geometrical characteristics and the distance characteristics of target bodies.

The invention discloses an underwater image splicing method based on multi-scale image fusion and SIFT features. The method comprises the following steps: 1) performing image enhancement on an underwater image by adopting an improved white balance algorithm and a linear interpolation-based CLAHE algorithm; 2) fusing an image after image enhancement by adopting a double pyramid image fusion methodto obtain an underwater preprocessed image; 3) performing underwater image registration on the underwater preprocessed image through an improved SIFT algorithm; and 4) calculating to obtain an image affine transformation matrix, and completing final underwater image splicing by adopting a linear gradual change synthesis algorithm. Experiments prove that the method fully considers the underwater environment and underwater imaging characteristics, and can obviously improve the effects and accuracy of underwater image enhancement, registration and splicing.

The invention belongs to the technical field of image processing and computer vision, combines an image defogging algorithm and a color constancy algorithm, and proposes a method capable of effectively restoring underwater image visual quality. The technical scheme adopted by the invention is that the underwater image restoration method includes the steps of performing defogging processing on degraded blue and green channels of an underwater image according to an underwater imaging data model, and correcting a degraded red channel on the basis of the restored pixel values of the blue and green channels according to a gray scale world color constancy algorithm. The underwater image restoration method provided by the invention is mainly applied to an image processing occasion.

The present invention discloses an optimization color correction and regression model-based underwater image restoration method. The method includes the following steps that: the color deviation of an underwater image is removed by adopting an optimization theory-based color correction algorithm; the global background light of the underwater image is estimated based on quadtree decomposition and optical properties; a training sample is synthesized, characteristics related to absorption functions are designed, and a regression model is trained; the trained regression model is used to estimate the absorption function of a red channel, a distance between a camera and a scene point is determined, and the absorption function of a blue channel can be estimated; and a clear underwater image is restored according to an underwater optical imaging model. Compared with the prior art, the optimization color correction and regression model-based underwater image restoration method of the present invention can better restore the true color of the underwater image; a global background light estimation method can effectively remove the influences of bright objects and suspended particles in the water, and therefore, the optimization color correction and regression model-based underwater image restoration method has higher accuracy and higher robustness; and a learning-based framework is adopted for the first time to estimate the absorption functions of the underwater imaging model, so that the method of the invention has better robustness.

The invention provides an underwater camera marking method applied to underwater binocular stereoscopic vision. The method includes the following steps: converting an image in water to an image in the air, then using the converted image to perform marking; analyzing and modeling underwater imaging points and air imaging points in case of the absence of water when focal points are at places where air and water parts, within water surface and outside the water surface so obtain the converting relation between the underwater imaging points and the air imaging points. The method herein, by converting the underwater image to the air image in the absence of water and then marking by using the air marking algorithm, can increase marking precision, conducts follow-up processing by continuing to use the air marking algorithm, and has strong expandability.

An apparatus and method permits measuring of near-direct forward scattering functions in water to enable acceptable underwater imaging for detection, classification, and identification of objects, such as mines. A source of light mounted on a housing member receiving ambient water emits a beam of light along an axis to a scattering detector assembly mounted on the base member. The detector assembly has a central active region disposed in the axis to receive portions of the light beam emitted along the axis and a plurality of concentric active regions are located radially outwardly from the central active region and the axis to receive scattered portions of the light beam. The central and concentric active regions provide signals representative of the magnitudes of the axial and scattered portions of the light beam for determination of the scattering function of the ambient water.

The invention provides hand-held imaging sonar and an imaging method thereof. The hand-held imaging sonar is characterized by comprising a watertight electronic tank, a display box, a battery box, andthe like, wherein a transducer group is mounted on the front-end surface of the watertight electronic tank and comprises a transmitting transducer array and a receiving transducer array which are mounted on a front-end cover of the electronic tank and are connected with an electronic system mounted in the electronic tank; the rear end surface of the electronic tank is provided with two watertightsockets which are used for connecting the display box and the battery box by a watertight cable; a handle for holding the sonar is mounted on a rear end cover of the electronic tank; the battery boxcan be carried by a driver together with other accompanied equipment; and the watertight electronic tank and the display box are fixedly connected so as to be held and operated by the driver. The hand-held imaging sonar helps the driver to observe muddy underwater environment and search objects, enables imaging to have real-time property and achieves underwater imaging and display.

The invention relates to an underwater plankton optical imaging device and method, and the device comprises an optical imaging unit (1) which is used for collecting scattered light or fluorescence emitted by an underwater plankton irradiated by a laser illumination unit, and carrying out the imaging of the underwater plankton; the laser lighting unit (2) comprises a laser lighting module and is used for lighting the underwater imaging area; wherein the laser illumination module emits a fan-shaped light layer to the illumination center to carry out imaging illumination. Compared with an existing device and method, the contrast ratio and the signal to noise ratio of underwater plankton imaging can be improved, and follow-up plankton identification and quantification based on image analysis are facilitated; in addition, the application mode and application scene of underwater plankton optical imaging can be expanded, meanwhile, the power consumption of the system is reduced, and compactness, miniaturization and intelligentization of the system are achieved.

An underwater positioning system (1) provides position information for a rover (2), moveable within a reference frame. The system may comprise: at least one beacon (4) having a light source (30), located at a fixed position within the reference frame; an underwater imaging device (10), moveable with the rover in the reference frame to observe the light source from different viewpoints and determine direction data representing a direction or change in direction of the light source with respect to the imaging device; an orientation sensor (14), associated with the imaging device to determine an orientation of the imaging device with respect to the reference frame and generate orientation data; and a scaling element (12,28,111,113,115,330a-c) for providing scaling data representative of a distance between the imaging device and the light source. Various different beacons may be provided. In alternative system implementations, the locations of light source(s) and underwater imaging device are reversed between rover and beacon(s).

The invention discloses an image restoration method based on underwater prior constraints. The method comprises the steps that firstly, a new image imaging model suitable for an underwater environmentis proposed by considering the difference of underwater three-channel attenuation; secondly, an effective color correction algorithm is used to remove color cast from an underwater image, and the Shades of Gray algorithm is used to estimate underwater environment light in the color-corrected image; thirdly, the boundary constraint of an original clear image is used to estimate the transmissivity,which can make up for the defect of inaccurate transmittance estimation of many current methods and the estimated transmissivity is refined; and finally, a clear restoration result is recovered by using the acquired transmissivity and the estimated environment light in combination with the new underwater imaging model. According to the invention, color distortion in the underwater image can be effectively removed; the image contrast can be enhanced; and the restored result is natural in color and clear in detail.

The invention discloses an underwater imaging device and method by using a laser point for scanning. The device comprises a light source, an imaging unit and a synchronous circuit; the light source isa laser point scanning light source, and the laser point scanning light source comprises a semiconductor laser module; the imaging unit is a camera or a vidicon of a CMOS image sensor with a rollingshutter exposure function; and the whole device is placed on the same side of a shot object. According to the underwater imaging device and method in the invention, the laser point is used for scanning the light source; compared with a linear light source or a strip-shaped light source, the structure is simpler, the size is smaller, and the energy utilization rate is higher. According to the device and the method in the invention, a plurality of semiconductor lasers can be used for synthesizing a beam of laser, so that the power of the light source can be improved, and the light source is enabled to contain multiple wavelengths; a better backward scattering eliminating effect or a better color correcting effect can be achieved by changing the wavelength of the light source under differentwater qualities. According to the underwater imaging device and method in the invention, the scanning speed is higher, the power consumption is lower, the stability is higher, and the size is smaller.

The invention discloses an underwater target ranging method based on binocular vision, and belongs to the field of computer vision, the method comprises the following steps: an improved underwater calibration algorithm is adopted to calibrate a camera and obtain internal and external parameters of the camera, and obtain a binocular image after underwater target correction; stereo matching is carried out by using the corrected binocular image to obtain an image parallax error; the angular point depth is obtained through similar triangle original solution calculation by utilizing the obtained image parallax; the distance test of the underwater target is completed. Based on an air binocular ranging algorithm, an underwater imaging model of a camera is combined, the influence of underwater factors on camera calibration is more comprehensively considered, factors such as the refractive index are added, the image correction capability of the camera during underwater work is enhanced, an improved Harris corner detection algorithm is adopted, the clustering phenomenon of underwater image corners can be relieved, selection of thresholds in the algorithm is avoided, mismatching points are reduced, and the accuracy and precision of image matching are improved.

The invention belongs to the field of computer vision, and relates to an underwater image enhancement method based on double U-nets. According to the invention, the method comprises the steps: settingtwo U-net connection convolutional network frameworks based on an underwater imaging physical model, wherein each U-net is composed of an encoding-decoding network, and an attention mechanism is added in front of the first U-net; by processing an input image and a grayscale image thereof, outputting a piece of feature information at each layer of a decoding structure for the second U-net, and estimating a transmission image; processing the underwater image through the second U-net to estimate the underwater image after red light compensation, and connecting the decoding structure with the feature information output by the first U-net to ensure that the details of the image enhancement process are not lost; and finally, dividing the imaging model by the transmission graph to obtain a finalresult. According to the method, the underwater image with serious color distortion and serious atomization can be effectively enhanced, and the details of the image are reserved.

The invention discloses an underwater image restoration method based on a convolutional neural network. The method comprises the following steps: (1) establishing an underwater optical imaging model;(2) integrating the underwater imaging model and existing indoor depth data into training data; (3) establishing a parameter estimation network, wherein the parameter estimation network comprises a sharing layer, a global background light estimation sub-network and a red channel transmissivity estimation sub-network, the sharing layer extracts common features for the two sub-networks, and the global background light estimation sub-network and the red channel transmissivity sub-network take output of the sharing layer as input and respectively map the input to global background light and red channel transmission; (4) restoring the underwater image; after a predicted global background light and red channel transmissivity graph is obtained through a parameter estimation network, calculating the transmissivity of a blue-green channel according to inherent characteristics of a water body, and finally, restoring an underwater image, and obtaining a clear underwater image.

The invention relates to an underwater imaging lens, solving the problems of limit effective imaging distance of underwater photography due to luminous energy loss and background interference caused by the adsorbing and scattering action on light by a water medium via the underwater imaging lens in the prior art. The underwater imaging lens comprises an optical system arranged in a sealing mechanism, wherein the optical system comprises a water sealing window, a front lens group, a diaphragm, a rear lens group and an image plane which are successively arranged along a light path incidence direction. According to a great quantity of real experiments, glass combinations are optimized, the focal power is reasonably distributed, 11 pieces of glass are adopted, the lanthanide-series glass material with low chromatic dispersion and high refractive index is chosen, aberrations, such as the spherical aberration, the comatic aberration, the astigmatic aberration, the field curvature, the distortion, the axial chromatic aberration and the vertical-axis chromatic aberration can be effectively corrected, and the imaging quality is improved.