47 results about "Gradient strength" patented technology

Object segmentation and tracking are improved by including directional information to guide the placement of an active contour (i.e., the elastic curve or ‘snake’) in estimating the object boundary. In estimating an object boundary the active contour deforms from an initial shape to adjust to image features using an energy minimizing function. The function is guided by external constraint forces and image forces to achieve a minimal total energy of the active contour. Both gradient strength and gradient direction of the image are analyzed in minimizing contour energy for an active contour model.

A method for detecting an edge and generating an interpolated edge pixel at a target pixel position between two lines of an interlace scan image first determines gradient intensities in the horizontal and vertical directions and then calculates the angle of the edge by comparing the gradient intensities. The interpolated pixel value is calculated from samples in the interlace scan image that lie along the identified angle and are proximate to the target pixel position. The method represents the gradient strengths and the difference between them as bit strings; locates the most significant non-zero bit in the larger gradient value; divides the value of the corresponding bit position in the difference string, and a predetermined number of following positions, by increasing powers of 2; sums the results; subtracts the sum from 1.0 and uses the inverse tangent function to calculate the angle of the edge.

A device for determining an edge histogram of an image based on information about a gradient strength and a gradient direction of a local gradient in an image content of a partial image of the image includes an allocator which is implemented to allocate the information about the gradient strength and the gradient direction based on an allocation regulation to an edge image in order to obtain edge type information. The allocation regulation is selected such that with a predetermined gradient direction at least three different allocated edge types exist mirroring the different gradient strengths. The device further includes an edge histogram determiner which is implemented to determine the edge histogram based on the edge type information so that in the edge type histogram at least three edge types having different allocated gradient strengths may be differentiated.

An object detecting device includes a calculating unit configured to calculate gradient intensity and gradient orientation of luminance for a plurality of regions in an image and calculate a frequency distribution of the luminance gradient intensity as to the calculated luminance gradient orientation for each of the regions, and a determining unit configured to determine whether or not an identified object is included in the image by comparing a plurality of frequency distributions calculated for each of the regions.

The invention provides a multi-factor two-dimension grey level histogram based threshold segmentation method belonging to the technical field of computer optical measurement. According to the invention, a multi-factor weight integrating image is created, a two-dimension grey level histogram is drawn and cross entropy is used for calculating the threshold value for segmenting the image. First, the weight integrating image based on three factors including neighborhood average gray level, gradient strength and gradient direction level. Further, a gray level image is combined and a gray level-integrated factor level two-dimension gray level histogram is drawn. Then an iteration method is adopted for solving gray level average values of foreground and background pixels. Finally, based on the minimum cross entropy, the optimal threshold value is calculated and the optimal threshold value is used for segmenting the image. The method provided by the invention solves a problem of image key information loss of a prior two-dimension gray level histogram; data accuracy and method reliability are ensured. The credibility of the threshold value and the image segmenting effect are improved. The whole threshold value segmenting algorithm is good in adaptability and high in validity.

The invention discloses an indoor scene flame detection method and belongs to the application fields of a visible light image, video processing and the like. In the prior art, whether an initial stage flame and a small flame which may cause a fire hazard exist is difficult to accurately detect and track. By using the method of the invention, the above problem is solved. In the invention, color space conversion and segmentation of the visible light image are taken as a basis, and a morphological characteristic of the flame is combined so as to carry out distinguishing. Because a component channel of the flame image in a YCbCr color space possesses obvious gradient intensity and gradient distribution characteristics, a support vector machine is used to learn and identify an HOG characteristic, and in a dynamic video, through a transient frame difference and a center of mass drift algorithm, tracking of a flame target is realized. A lot of indoor flame image and video sample tests show that the method has advantages that an identification rate is high; a detection speed is fast; a false alarm rate is low and reliability is high compared to a traditional method. The method aims at detection and tracking of the initial stage flame, the small flame and the like.

The invention provides a full-automatic segmentation method for a mixed tissue image of a simulated colonoscopy, comprising the following steps of: selecting a suitable threshold value of the air and of the enteral residual liquid; carrying out an initial segmentation for the enteral area through a traditional threshold method; wiping a local volume effect between the air and the enteral residual liquid through a vertical filter; conducting an enteral segmentation through a region growing method; enhancing the boundaries of the colon and other issues through a gradient intensity region growing method; repeating a wiping of the local volume effect between the air and the enteral residual liquid through the vertical filter for the inner part of the colon with enhanced boundaries. The full-automatic segmentation method for the mixed tissue image of a simulated colonoscopy overcomes the problems of the traditional threshold segmentation, eliminates the impacts from the local volume effect, and renders the segmentation results better in conformity with the actual conditions.

An image processing apparatus includes: a gradient information calculating unit that calculates gradient information of each of pixels, based on pixel values of an intraluminal image; a closed region creating unit that, based on the gradient information, creates a closed region satisfying a condition where the closed region does not include, on the inside thereof, any pixel of which the gradient strength is equal to or higher than a predetermined value, and also, the boundary of the closed region does not curve toward the interior of the closed region, with a curvature equal to or larger than a predetermined value; and an abnormal part detecting unit that detects an abnormal part from the inside of the closed region.

The present invention relates to an arrangement (10) for influencing and/or detecting magnetic particles (100) in a region of action (300), which comprises selection means (210) for generating a magnetic selection field (211) having a pattern in space of its magnetic field strength such that a first sub-zone (301) having a low magnetic field strength and a second sub-zone (302) having a higher magnetic field strength are formed in the region of action (300). The arrangement further comprises drive means (220) for changing the position in space of the two sub-zones (301, 302) in the region of action (300) by means of a magnetic drive field (221) so that the magnetization of the magnetic material changes locally. The arrangement further comprises receiving means (230) for acquiring detection signals, which detection signals depend on the magnetization in the region of action (300), which magnetization is influenced by the change in the position in space of the first and second sub-zone (301, 302). Control means (76) are further introduced for controlling the selection means (210) to individually set the gradient strength of at least one of the static magnetic gradient fields (211) in a desired direction.

The invention provides an image processing apparatus and an image processing method. The image processing apparatus includes a gradient strength calculating unit that calculates a gradient strength of a pixel value of each pixel based on an intraluminal image that is a captured image of an intralumen; a closed region extracting unit that extracts a closed region from the intraluminal image, the closed region satisfying conditions that the pixel of which gradient strength is a predetermined value or more is not included in the closed region and a boundary of the closed region does not bend with a predetermined curvature or higher toward an inner side of the closed region; and an abnormal portion detecting unit that detects an abnormal portion inside the closed region. The closed region extracting unit includes an initial closed region setting unit that sets an initial shape of the closed region; an energy calculating unit that calculates values of a plurality of types of energy including at least energy determined by an outer shape of the closed region and energy determined by the gradient strength in the closed region; an energy-weighted sum calculating unit that calculates a weighted sum of the plurality of types of energy; and a closed region updating unit that updates a shape of the closed region within an update range based on the weighted sum. The closed region updating unit includes an update range determining unit that determines the update range in which the shape of the closed region is updated based on any one of the values of the plurality of types of energy.

In a method for the calculation of individual elements of a matrix to correct artifacts in magnetic resonance images that are reconstructed from measurement data acquired using an MR pulse sequence, in which gradients are switched simultaneously during the radiation of at least one non-selective excitation pulse, at least one excitation profile of an excitation pulse used to acquire measurement data is loaded into a process, the profile depending on the measured location x and the measured k-space point k and the gradient strength applied in the measurement. From each loaded excitation profile, an element of a transposed, inverted disturbance matrix is calculated which corresponds to the location x and the measured k-space point k. Instead of a Fourier back-transformation, matrix inversion is used for the image reconstruction of a corrected image.

Provided is an image processing apparatus and an image processing method. The apparatus includes a calculating unit that calculates gradient strength of respective pixel values based on an intraluminal image, an extracting unit that extracts a closed region from the image, and a detecting unit that detects an abnormal portion of the closed region. The closed region satisfies conditions that the pixel of which gradient strength is a predetermined value or more is not included in the closed region and a boundary of the closed region does not bend with predetermined curvature or higher toward an inner side of the closed region. The extracting unit includes a setting unit that sets an initial closed region based on the gradient strength, an energy calculating unit that calculates values of types of energies based on an outer shape of the closed region and the gradient strength, and an energy weighted-sum calculating unit that calculates a weighted sum of the types of energy.

The embodiment of the invention provides a magnetic resonance scanning strategy determination method and a magnetic resonance scanning system. The magnetic resonance scanning strategy determination method comprises the steps of acquiring the gradient strength of a logic axis of a gradient pulse sequence in a set time window, and determining the gradient average power of the logic axis according tothe gradient strength; determining a first gradient average power matrix in a physical coordinate system according to the gradient average power of the logic axis and preset rules; determining the maximum gradient average power and a direction of the maximum gradient average power according to the first gradient average power matrix; and determining a magnetic resonance scanning strategy according to the maximum gradient average power and the direction of the maximum gradient average power. The embodiment of the invention solves problems that the calculation for the maximum average power is great in calculation amount, the operation is complex, and the time spent on determining the magnetic resonance scanning strategy is long, a scanning strategy can be quickly determined according to thecalculation result, and clinical scanning is ensured to be performed smoothly.

Embodiments of the present invention provide field test devices and methods for testing the compressive gradient strength of installed vehicle arresting systems, such as those installed on airport runways. Current methods of testing such arresting systems are conducted on sample materials in-house, and these methods are not applicable or useful when tests need to be conducted on currently-installed systems in the field.

The invention discloses a gradient coil for magnetic resonance imaging and a processing method thereof. The gradient coil comprises an insulating base plate and at least three sub-coils; at least onesub-coil is a curved coil, and the remaining sub-coils are planar coils; the first surface of the insulating base plate forms a curved portion and the second surface forms a planar portion; the curvedcoil is fixed on the curved portion; the shape of the curved coil is adapted to the shape of the curved portion; and the planar coil is fixed on the planar portion. The invention also discloses a processing method for a gradient coil for magnetic resonance imaging. Deformation of the coil during the processing process can be effectively avoided, the processing precision and the performance of thegradient coil are improved, the efficiency and the gradient strength of the gradient coil are improved, image distortion can be effectively avoided, and the image quality is improved.

The present invention provides an image boundary extraction method and system. The method comprises: acquiring gradient strength and a gradient direction of each pixel point of an image; according to the gradient strengthen and the gradient direction of each pixel point, determining strong boundary pixel points and weak boundary pixel points of the image; using row as the unit, and according to the strong boundary pixel points and the weak boundary pixel points, determining and obtaining second canny boundary pixel points respectively in order from top to bottom and in order from bottom to top; and according to the strong boundary pixel points and the second canny boundary pixel points, extracting a boundary of the image. According to the image boundary extraction method and system provided by the present invention, parallelization of boundary connection is realized and the speed of canny boundary connection is improved.

In a method to operate a magnetic resonance apparatus with a magnetic resonance sequence—in particular a PETRA sequence—in which k-space is radially scanned for an image acquisition in a first region of k-space that does not include the center of k-space, and in which an excitation pulse is radiated as the full strength of at least two phase coding gradients is reached, and in which k-space is scanned in a Cartesian manner—in particular by single point imaging—in a second region of k-space remaining without the first region, the gradient strength corresponding to a shortest total acquisition time is determined automatically from predetermined sequence parameters and/or sequence parameters defined by a user. The sequence parameters parameterize the magnetic resonance sequence and describe the number of acquisitions for the regions of k-space and the repetition time, and the gradient strength is indicated to a user as a recommendation and/or is set automatically in the implementation of the magnetic resonance sequence.

The invention discloses a double-gradient-strength passenger car stand column structure. The double-gradient-strength passenger car stand column structure is characterized by consisting of a longitudinal gradient strength stand column and a transverse filling gradient density foam material. As the transverse filling density foam material is bonded on the inner side wall of a gradient strength L-shaped plate in the length direction of the gradient strength L-shaped plate, the collision force of the key part-stand column of a passenger car closed loop structure can be guaranteed to be matched with the strength of the corresponding position in the passenger car tilting process, the stress of each surrounding part of a passenger car is more uniform, and the unloading of external impact load is facilitated. In addition, the transverse filling gradient density foam material enhances the rigidity of the stand column, and the energy absorption is more stable in the tilting of the passenger car, so that secondary collision casualties are reduced. Meanwhile, the foam material also achieves the effects of sound isolation and heat insulation, and improves the tilting safety and the comfort of the passenger car.

The invention relates to a clustering method using a two-stage local binary pattern (2SLBP). The method comprises the steps of generating a gradient direction value according to a central sub-block and adjacent sub-blocks of each patch of an image; quantizing each gradient direction value to generate a quantized gradient direction value; generating a gradient strength value according to each gradient direction value; quantizing each gradient strength value to generate a quantized gradient strength value; connecting the quantized gradient direction values with the quantized gradient strength values in series to generate a 2SLBP value; and using the 2SLBP value as an pointer to execute the clustering of super-resolution image processing.