Improved high-frequency high frame rate duplex ultrasound linear array imaging system

The digital micromirror device DMD is widely used in visible light projection, special-purpose spatial light modulation, and infrared scene simulation, due to its high resolution, uniformity and energy concentration. In some applications that require high frame rate scene image display, it is necessary to ensure that the DMD displays high gray level images at a high frame rate. However, the display frame rate of the pulse width modulation (PWM) method is limited by the minimum time required for DMD loading data, unable to achieve high frame rate display. Although the DMD binary display mode can meet the requirements of high frame rate display, it cannot meet the requirements of high gray level. The paper proposes an image display method that uses light source and DMD to synchronize modulation. Decompose the high-order gray image into bit planes according to the gray threshold, and the DMD displays each bit plane in binary mode under the trigger of an sync pulse. The intensity of the illumination laser source is modulated by an acousto-optic modulator to match the bit plane and the radiated laser power. This method makes use of the function of high frame rate display in DMD binary mode cooperate with light intensity modulation of illumination laser source, and realizes high frame rate and high dynamic range image display. With this method, the maximum frame rate of 8-bit gray level image with 1920 ×1080 resolution can reach 2KHz. The experimental system has realized 200Hz frame rate display of 8-bit gray level image with 1920 ×1080 resolution.

The purpose of this study was to assess whether or not high frame rate (HFR) videos recorded using high-speed digital imaging (HSDI) improve the visual recognition of the motions of the laryngopharyngeal structures during pharyngeal swallow in fiberoptic endoscopic evaluation of swallowing (FEES). Five healthy subjects were asked to swallow 0.5ml water under fiberoptic nasolaryngoscopy. The endoscope was connected to a high-speed camera, which recorded the laryngopharyngeal view throughout the swallowing process at 4000 frames/s (fps). Each HFR video was then copied and downsampled into a standard frame rate (SFR) video version (30 fps). Fifteen otorhinolaryngologists observed all of the HFR/SFR videos in random order and rated the four-point ordinal scale reflecting the degree of visual recognition of the rapid laryngopharyngeal structure motions just before the 'white-out' phenomenon. Significantly higher scores, reflecting better visibility, were seen for the HFR videos compared with the SFR videos for the following laryngopharyngeal structures: the posterior pharyngeal wall (p=0.001), left pharyngeal wall (p=0.015), right lateral pharyngeal wall (p=0.035), tongue base (p=0.005), and epiglottis tilting (p=0.005). However, when visualized with HFR and SFR, 'certainly clear observation' of the laryngeal structures was achieved in <50% of cases, because all the motions were not necessarily captured in each video. These results demonstrate the use of HSDI in FEES makes the motion perception of the laryngopharyngeal structures during pharyngeal swallow easier in comparison to SFR videos with equivalent image quality due to the ability of HSDI to depict the laryngopharyngeal motions in a continuous manner.

Charge coupled device(CCD) is one kind of photoelectric solid-state imaging device with excellent performance. It has the features of large array and good image quality. Working under very complex driving timing, it usually has low frame frequency and can not meet the demand of high imaging frame rate. The method of equivalent high frame rate imaging technique is introduced based on normal CCD in this paper. Some CCDs can be drived via electrodes separately. To meet the imaging demands of high frame rate, high resolution and high quality of two frame imaging technique for pulse light images, the right kind of CCDs should be adopted. The most important is that the CCD electrodes must be controlled directly and respectively. The charge transfer period is a key point while designing CCD driving timing for separate pulse light integration, charge package transfer and readout for two pulse light images. The validation experiments for the principle of equivalent high frame rate exposure of two pulse light images has been accomplished. It is shown that two pulse light images with interval of about 2 μs can be distinguished while all CCD’s inherent excellent performance are retained. A kind of two framing camera system with simple structure can be developed based on this principle.

The use of flat panel detectors in computed tomography (CT) systems can improve resolution, reduce system cost, and add operational flexibility by combining fluoroscopy and radiography applications within CT systems. However, some prior studies have suggested that flat panel detectors would not perform well in CT applications due to their lack of high dynamic range, lag artifacts, and inadequate frame rate. The purpose of this study was to perform a physical evaluation of a prototype flat panel detector capable of high frame rates and extended dynamic range. The flat panel detector used had a pixel size of 194 microns and a matrix size of 2048x1536. The detector could be configured for several combinations of frame rate and matrix size up to 750 frames per second for a 512x16 matrix size with 4x4 binning. The evaluation was performed in terms of the MTF and DQE as a function of frame rate and exposure at the IEC RQA5 (~75 kVp, 21 mm Al) beam quality. The image lag was evaluated in terms of temporal-frequency dependent transfer function. Offset shift were also evaluated. Preliminary results indicate 0.1 MTF at 0.92 cycles/mm and DQE(0) of approximately 0.8, 0.6, 0.4, and 0.22 at 0.144, 0.065, 0.035, and 0.008 mR per frame exposures. The temporal MTF exhibited a low-frequency drop and a value of 0.5 at the Nyquist frequency. Offset shift was negligible. Considering high frame rate capabilities of the new detector, the results suggest that the detector has potential for use in real-time CT applications including CT angiography.

Current proposals for Advanced Television for the United States are based upon the premise that temporal and resolution layering are inefficient. These proposals therefore only provide a menu of individual formats from which to select, but each format only encodes and decodes a single resolution and frame rate. In addition, it is being suggested by some people that interlace is required, due to their claimed need to have one thousand lines at high frame rates, but based upon the notion that such images cannot be compressed within the available 18mbits/second. — This paper discusses an approach to image compression which demonstrably achieves thousand line image compression at high frame rates with high quality. It also achieves both temporal and spatial scalability at this resolution at high frame rates within the available 18mbits/second. This technique efficiently encodes 2 MegaPixel images at 72 frames per second, achieving over twice the compression ratio being proposed by ACATS for advanced television. Further, this proposed technique is more robust than the current unlayered ACATS format proposal for advanced television, since all of the bits may be allocated to the lower resolution base layer when stressful image material is encountered. — Thus, a number of key technical attributes are provided by this proposal, allowing substantial improvement over the ACATS proposal. These improvements include: the replacement of numerous resolutions and frame rates with a single layered resolution and frame rate; no need for interlace in order to achieve a thousand lines of two million pixels at high frame rates: and compatibility with computer displays through the use of 72 frames per second.

The digital revolution changed film production and its aesthetics in many ways. Although motion is a defining feature of moving images, it is also one of their most problematic aspects because of blurred images or other signal processing artifacts. An artistic research project was conducted to test the effects of high frame rates (HFR) on visual perception. Typical camera movements were recorded in different frame rates (24 / 48 / 96 fps) to generate test sequences for a cinema experiment. 69 participants were measured with an SMI eye tracking device and a questionnaire in a within subjects design. The results show that the participants valued the higher image quality of HFR, but rated the standard frame rate as more realistic and indicated more presence. Moreover, HFR produced a higher number of fixations than the standard frame rate. Open questions for future research projects on HFR will be discussed.

The frame rate (FR) of a video plays an important role in affecting the perceptual video quality. Most studies about the effect of FR on the video quality mainly focused on low frame rate, e.g. less than 30 frames per second (fps), at low resolutions like CIF or QCIF. As the video frame rate and resolution advance, we reconsider this issue and investigate the relationship between frame rate and the perceptual video quality under high frame rate and high resolution. In this paper, we discuss the impact of frame rate on the perceptual quality of High Definition (HD) video with high frame rates (up to 120 fps) considered. Firstly, we design and conduct subjective experiment to construct the video dataset, which includes video sequences at different frame rates and the corresponding mean opinion scores (MOS) which represent the perceptual video quality. Based on the MOS results, we analyze how perceptual video quality changes as frame rate varies among different video sequences and propose some meaningful findings. The video dataset will be made publicly available. We deem that this study will enrich video quality assessment and benefit the development of high frame rate and high definition video business.KeywordsVideo quality assessmentSubjective experienceHigh frame rateHigh definition

This paper presents our implementation of a multi-view autostereoscopic 3D display system by using time-multiplexing approach, digital micro-mirror devices (DMD), and the optical Wedgereg. The whole system consists of three major parts: high frame rate DMD projector, an active shutter, and an optical Wedgereg. This research investigates and develops the approaches to interface and control DMDs at very high bit rates and ultra-high frame rates to drive a novel flicker-free 3D flat panel device, with a wide viewing area and without need of special viewing glasses or head-tracking system. It needs to design a digital interface circuit capable of receiving video image data in a conventional format and translating it into a form appropriate for display on a DMD light modulator. This approach differs from existing ones in that it facilitates the modulation of the DMD to achieve much high frame rates, though with a trade-off in greyscale resolution. The outcomes of this research will have the great potential for commercialising the autostereoscopic display systems

For gamers, high frame rates are important for a smooth visual display and good quality of experience (QoE). However, high frame rates alone are not enough as variations in the frame display times can degrade QoE even as the average frame rate remains high. While the impact of steady frame rates on player QoE is fairly well-studied, the effects of frame rate variation is not. This paper presents a 33-person user study that evaluates the impact of frame rate variation on users playing three different computer games. Analysis of the results shows average frame rate alone is a poor predictor of QoE, and frame rate variation has a significant impact on player QoE. While the standard deviation of frame times is promising as a general predictor for QoE, frame time standard deviation may not be accurate for all individual games. However, 95% frame rate floor -– the bottom 5% of frame rates the player experiences –- appears to be an effective predictor of both QoE overall and for the individual games tested.

User performance in virtual environments with degraded visual conditions due to low frame rates is an interesting area of inquiry. Visual content shown in a low frame rate simulation has the quality of the original image, but persists for an extended period until the next frame is displayed (so-called high persistence-HP). An alternative, called low persistence (LP), involves displaying the rendered frame for a single display frame and blanking the screen while waiting for the next frame to be generated. Previous research has evaluated the usefulness of the LP technique in low frame rate simulations during a static target acquisition task. To gain greater knowledge about the LP technique, we have conducted a user study to evaluate user performance and learning during a dynamic target acquisition task. The acquisition task was evaluated under a high frame rate, (60 fps) condition, a traditional low frame rate HP condition (10 fps), and the experimental low frame rate LP technique. The task involved the acquisition of targets moving along several different trajectories, modeled after a shotgun trap shooting task. The results of our study indicate the LP condition approaches high frame rate performance within certain classes of target trajectories. Interestingly we also see that learning is consistent across conditions, indicating that it may not always be necessary to train under a visually high frame rate system to learn a particular task. We discuss implications of using the LP technique to mitigate low frame rate issues as well as its potential usefulness for training in low frame rate virtual environments.

In accordance with advances in camera technology, the requirement of high-quality video has greatly increased. Among the factors required for high-quality video are a high-resolution and a high frame rate. However, the limitation of the pixel transfer rate restricts compatibility of a high-resolution and a high frame rate in commercial camera. We propose a dual-sensor camera that consists of two cameras: one with a high-resolution and a low frame rate and the other with a low-resolution and a high frame rate. The system is capable of capturing two different image sequences: high-resolution images and high-frame-rate images. A sensor calibration for the dual-sensor camera is also proposed.

The analysis of knee kinematics and kinematics during high-risk movements associated with anterior cruciate ligament (ACL) injury is essential to studying the mechanism of ACL injury. Motion capture at low frame rates may not always detect the actual peak values during high-speed movements. However, the knee kinetic differences between various frame rate measurements during high-risk movements have not been reported. The purpose of this study was to investigate whether 3D knee kinetics would be measured differently between frame rates such as a high frame rate (1200 Hz), 400 Hz, 240 Hz and the popular low frame rate (120 Hz). Knee kinetics during a single-leg drop landing and side-step cutting under different frame rates were repeatedly measured and statistically compared. Peak knee valgus and tibial internal rotation moments measured at a popular low frame rate were significantly lower than those measured at the other frame rates of 400 Hz and 1200 Hz. The peak anterior and superior forces measured at the highest (1200 Hz) frame rate were significantly higher than those measured at any other frame rates. In addition, the variations in the peak kinetic values were significantly larger at the lowest frame rate capture and trended toward being smaller at the higher frame rates. In conclusion, significant differences in the knee kinetics between the frame rates suggest that the high frequency capturing increases the accuracy of the knee kinetics measurement for high risk maneuvers for the study of ACL injury.

Controlled experiments were designed to evaluate the high frame rate (HFR) imaging method and compare it with the conventional D&S method on sidelobe, spatial resolution, contrast resolution, and detectability. A point object or modified ATS512 contrast-detail tissue-mimicking phantom was placed in a water tank, and a modified Acuson V2 array transducer was used. RF echoes were obtained with a homemade HFR imaging system. Data were constructed with both the Fourier-based method (with 1, 11, 19, and 91 transmissions) and the D&S method of 91 transmissions. The Fourier-based method provides a continuous compromise between image frame rate and image quality. At the same frame rate (91 transmissions), the Fourier-based method has a higher resolution and lower sidelobe than the D&S method, even at its transmission focal distance.

Effects of Phase Aberration and Noise on Extended High Frame Rate Imaging

This paper presents a method for optimizing parameters affecting the image quality in plane wave imaging. More specifically, the number of emissions and steering angles is optimized to attain the best images with the highest frame rate possible. The method is applied to a specific problem, where image quality for a λ -pitch transducer is compared with a λ /2-pitch transducer. Grating lobe artifacts for λ -pitch transducers degrade the contrast in plane wave images, and the impact on frame rate is studied. Field II simulations of plane wave images are made for all combinations of the parameters, and the optimal setup is selected based on Pareto optimality. The optimal setup for a simulated 4.1-MHz λ -pitch transducer uses 61 emissions and a maximum steering angle of 20° for depths from 0 to 60 mm. The achieved lateral full-width at half-maximum (FWHM) is 1.5λ and the contrast is -29 dB for a scatterer at 9 mm ( 24λ ). Using a λ /2-pitch transducer and only 21 emissions within the same angle range, the image quality is improved in terms of contrast, which is -37 dB. For imaging in regions deeper than 25 mm ( 66λ ), only 21 emissions are optimal for both the transducers, resulting in a -36 dB contrast at 34 mm ( 90λ ). Measurements are performed using the experimental SARUS scanner connected to a λ -pitch and λ /2-pitch transducer. A wire phantom and a tissue mimicking phantom containing anechoic cysts are scanned and show the performance using the optimized sequences for the transducers. FWHM is 1.6λ and contrast is -25 dB for a wire at 9 mm using the λ -pitch transducer. For the λ /2-pitch transducer, contrast is -29 dB. In vivo scans of the carotid artery of a healthy volunteer show improved contrast and present fewer artifacts, when using the λ /2-pitch transducer compared with the λ -pitch. It is demonstrated with a frame rate, which is three times higher for the λ /2-pitch transducer.