Digital Scan Conversion Research Articles

Analysis of the Application Prospect of Computer Image Processing Technology in UI Design

In order to improve the interface experience effect of the mobile terminal software, this paper improves the UI design by combining computer image processing technology and improves the diffusion algorithm for images by improving the diffusion model, improving the diffusion coefficient and adaptively selecting the diffusion threshold. Moreover, this paper has carried out deep research on coordinate transformation and image interpolation and stored the result of coordinate transformation in the coordinate transformation table and weight table. In addition, this paper proposes an improved digital scan conversion method based on a lookup table and constructs an improved UI design system model. Through the analysis of experimental data, it can be seen that the application effect of computer image processing technology in UI design is very good, and it can effectively promote the improvement of UI design technology.

Monitoring microwave ablation using ultrasound backscatter homodyned K imaging: Comparison of estimators

The feasibility of ultrasound backscatter homodyned K model parametric imaging (termed homodyned K imaging) to monitor coagulation zone during microwave ablation was investigated. Two recent estimators for the homodyned K model parameter, RSK (the estimation method based on the signal-to-noise ratio, the skewness, and the kurtosis of the amplitude envelope of ultrasound) and XU (the estimation method based on the first moment of the intensity of ultrasound, X statistics and U statistics), were compared. Firstly, the ultrasound backscattered signals during the microwave ablation of porcine liver ex vivo were processed by the noise-assisted correlation algorithm, envelope detection, sliding window method, digital scan conversion and color mapping to obtain homodyned K imaging. Then 20 porcine livers' microwave ablation experiments ex vivo were used to evaluate the effect of homodyned K imaging in monitoring the coagulation zone. The results showed that the area under the receiver operating characteristic curve of the RSK method was 0.77 ± 0.06 (mean ± standard deviation), and that of the XU method was 0.83 ± 0.08 (mean ± standard deviation). The accuracy to monitor the coagulation zone was (86 ± 10)% (mean ± standard deviation) by the RSK method and (90 ± 8)% (mean ± standard deviation) by the XU method. Compared with the RSK method, the Bland-Altman consistency for the coagulation zone estimated by the XU method and that of actual porcine liver tissue was higher. The time for parameter estimation and imaging by the XU method was less than that by the RSK method. We conclude that ultrasound backscatter homodyned K imaging can be used to monitor coagulation zones during microwave ablation, and the XU method is better than the RSK method.

Pixel based focusing for photoacoustic and ultrasound dual-modality imaging

It is desired that the same imaging functional modules such as beamformation, envelope detection, and digital scan conversion (DSC) are employed for the efficient development of a cross-sectional photoacoustic (PA) and ultrasound (US) dual-modality imaging system. The beamformation can be implemented using either delay-and-sum beamforming (DAS-BF) or adaptive beamforming methods, each with their own advantages and disadvantages for the dual-modality imaging. However, the DSC is always problematic because it causes blurring the fine details of an image, e.g., edges. This paper demonstrates that the pixel based focusing method is suitable for the dual-modality imaging; beamformation is directly conducted on each display pixel and thus DSC is not necessary. As a result, the artifacts by DSC are no longer a problem, so that the proposed method is capable of providing the maximum spatial resolution achievable by DAS-BF. The performance of the proposed method was evaluated through simulation and ex vivo experiments with a microcalcification-contained breast specimen, and the results were compared with those from DAS-BF and adaptive beamforming methods with DSC. The comparison demonstrated that the proposed method effectively overcomes the disadvantages of each beamforming method.

An FPGA-based architecture of DSC–SRI units specially for motion blind ultrasound systems

Digital scan conversion (DSC) and speckle reduction imaging (SRI) are basic back-end units of an ultrasound imaging system. In a B-mode ultrasonography (USG) system, DSC is necessary to display a two dimensional image of a tissue structure. Speckle noise, present in an USG system, affects the quality of images observed. Moreover, motion blurring is observed while examining non-stationery organs like the heart. To address these issues, a high speed VLSI design of the USG back-end unit is presented in this paper. The back-end is designed in such a way that it can be integrated with the front-end of the USG system. An FPGA platform is used to prototype these units. Massive usage of the parallel-pipelining technique has helped in achieving high throughput at low power. The DSC architecture operates at 14.66 MHz and is capable of scan converting 132 raw frames per second. Similarly, the SRI unit operates at 221 MHz and is capable of de-speckling images of size 640 × 480 at 698 fps. Therefore, it is possible to investigate objects without motion blur using these units. System level integration issues of the DSC---SRI units are also covered in this paper.

VLSI-DSP based real time solution of DSC–SRI for an ultrasound system

In this paper, VLSI-DSP based a real time solution for Digital Scan Conversion (DSC) and speckle reduced imaging (SRI) of an ultrasonography (USG) are proposed. DSC is needed to convert the polar format data to Cartesian coordinate to make them compatible for the display device. To reduce Moirè artifact a new interpolation algorithm is proposed which is a combination of warped distance based adaptive bilinear interpolation method and modified selective sampling technique. This new algorithm is implemented on TMS320C64x + DSP and is capable of processing 640 × 480 size images at the rate of 83 frames per second. Moreover, to reduce speckle noise a modified aggressive region growing filter is implemented on Xilinx XC2VP30 FPGA. It operates at 128.29 MHz frequency, which is equivalent to processing 417 frames per second. With such high frame rate, motion blind detection of the objects may be possible using USG.

An Improved High-Accuracy CORDIC Algorithm for DSC in Endoscopic Ultrasonography System

An Improved High-Accuracy CORDIC (COordinate Rotation Digital Computer) algorithm for digital scan conversion is presented in this paper to enhance the accuracy and speed of coordinate conversion for Endoscopic Ultrasonography. Several optimization methods are carried out to make coordinate conversion implemented more exactly with fewer resources of FPGA. In the paper, the Cartesian coordinates are re-demarcated to save LE (Logic Element) resources of FPGA. The bit width of data, the scale factor correction and the convergence range are all optimized to improve the accuracy of the algorithm. Further more, a special processing for the near-field data is carried out to reduce the errors of digital scan conversion. With a full pipeline structure implemented on FPGA, the Improved High-Accuracy CORDIC algorithm is validated by both simulation and real-time ultrasound imaging experiment, making the accuracy enhanced and the image quality improved.

Simulation of digital scan conversion for ultrasound systems using a digital signal processor

B-mode ultrasound systems use digital scan conversion (DSC) to display data in a Cartesian coordinate system acquired in a polar coordinate format. Image quality depends on the quality of the interpolation algorithm applied to the unsampled pixels to avoid artefacts. In this paper, a warped distance-based adaptive bilinear interpolation technique with selective sampling is proposed and has been successfully simulated using a Texas Instruments (TI) digital signal processor series TMS320C64x+ cycle accurate simulator. The algorithm enhances both the detail in the different regions as well as preserving the smooth regions within the image, yielding better image quality with less computational complexity. Optimized implementation of the algorithm supports software pipelining. Additionally, the approach speeds up the computation by utilizing the ability of very long instruction word processor to perform multiple operations in parallel. The experimental results show that the DSC is capable of supporting 83 frames per second without sacrificing the image quality for a raw input image of size, 512 × 256 scanned with an angle of 58° and output video graphics array (640 × 480) display.

Design and development of a high-performance third-generation hand-held thermal camera

A high-performance hand-held thermal imaging camera has been developed, based on a 320256-element InSb infrared focal plane array FPA operating in the medium-wave infrared region. The primary design objective was a low-cost, compact, lightweight, and por- table thermal camera with a recognition range of 2 km. A staring FPA based on InSb technology with long and variable integration time pro- vides the answer best suited to these requirements. The system pro- vides such features as two-point and adaptive nonuniformity correction, bad-pixel detection and replacement, dynamic range compression, con- trast and edge enhancement, histogram equalization, and digital scan conversion for CCIR-B-compatible output. The design methodology and the performance are presented. © 2006 Society of Photo-Optical Instrumentation

A NEW DIGITAL SCAN CONVERSION ARCHITECTURE FOR ULTRASONIC IMAGING SYSTEMS

Digital scan conversion (DSC) is the process of converting received ultrasound signals, or echoes, in multi-scan lines, at varying angles (polar coordinate), to a Cartesian raster format for displaying. In this paper, we propose a new DSC technique that uses nearest-neighbor interpolation and the linear interpolation between adjacent scan lines to reduce artifacts on the far field, with smaller angular separation between the interpolated lines. A hardware implementation is described that uses only a FIFO register and a display memory. Rapid prototyping using an ARM processor with FPGA resources is achieved to validate the operation of the described system. Experimental results of the implemented design demonstrated the expected operation of the reduced complexity architecture in term of needed memory. Also, the performance of retrieved images were increased.

Digital signal and image processing in echocardiography

Digital signal and image processing techniques are acquiring an increasingly important role in the generation and analysis of cardiac images. This is particularly true of 2D echocardiography, in which image acquisition, manipulation, and storage within the echocardiograph, as well as quantitative analysis systems, depend upon digital techniques. The increasing role of computers in echocardiography it essential that echocardiographers and technologists understand the basic principles of digital techniques applied to echocardiographic instrumentation and data analysis. In this article, we have discussed digital techniques as applied to image generation (digital scan conversion, preprocessing, and postprocessing) as well as to the analysis of image data (computer-assisted border detection, 3D reconstruction, tissue characterization, and contrast echocardiography); a general introduction to off-line analysis systems was also given. Experience with other cardiac imaging methods indicates that digital techniques will likely play a dominant role in the future of echocardiographic imaging.

Interpolation scan conversion in pulse-echo ultrasound.

Some disadvantages of current digital scan conversion techniques are reviewed. An improved system is described which uses linear interpolation between available sampled data points to provide an estimate of the echo reflectivity at each grid point in the image. This approach avoids the problems of “missed pixels” inherent in the current approach, and the need to provide some smoothing or blurring function to remove them. The interpolated scan conversion allows data line spacing to be increased, leading to a reduced scan time for static scans and increased frame-rate for real-time, while retaining all the resolution available from the ultrasound system.

Interpolation scan conversion in pulse-echo ultrasound

Some disadvantages of current digital scan conversion techniques are reviewed. An improved system is described which uses linear interpolation between available sampled data points to provide an estimate of the echo reflectivity at each grid point in the image. This approach avoids the problems of “missed pixels” inherent in the current approach, and the need to provide some smoothing or blurring function to remove them. The interpolated scan conversion allows data line spacing to be increased, leading to a reduced scan time for static scans and increased frame-rate for real-time, while retaining all the resolution available from the ultrasound system.

THE SHINPADS STANDARD DISPLAY

ABSTRACTTo date, individual functions on a ship have had their own unique display. For example, Radar, ASW, TV and Engine Monitoring subsystems have performed the man/machine interface through dedicated and different display media. Digital electronic technology now enables a single multipurpose display to be configured capable of handling a wide variety of sensors and computer‐generated synthetic information. This results in considerable savings in inventory, spares, training and documentation leading to substantial reductions in life‐cycle costs.The multipurpose display is based on Digital Scan Conversion techniques. The display medium itself is a very high resolution TV monitor (1225‐lines) refreshed from a digital memory built up from high density Random Access Memory integrated circuits. This memory is loaded from a variety of processing modules formatting wide‐band video from a number of sensors. For those rare functions where it is not cost effective to perform the processing with the display, this is done with the sensor and transmitted to the Standard Display over a standard digital video channel.The memory also has a port addressed from a display processor through a graphics generator, to implement intelligent terminal functions such as track handling. High level control is established over the SHINPADS Bus.A prototype of the radar scan conversion portion of this display was built in 1977 and is currently being evaluated in the field. A Pre‐production Model of the complete multi‐sensor SHINPADS Standard Display will be available mid‐1979.