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Biomedical image segmentation plays a pivotal role in medical imaging, facilitating precise identification and delineation of anatomical structures and abnormalities. This review explores the application of the Denoising Diffusion Probabilistic Model (DDPM) in the realm of biomedical image segmentation. DDPM, a probabilistic generative model, has demonstrated promise in capturing complex data distributions and reducing noise in various domains. In this context, the review provides an in-depth examination of the present status, obstacles, and future prospects in the application of biomedical image segmentation techniques. It addresses challenges associated with the uncertainty and variability in imaging data analyzing commonalities based on probabilistic methods. The paper concludes with insights into the potential impact of DDPM on advancing medical imaging techniques and fostering reliable segmentation results in clinical applications. This comprehensive review aims to provide researchers, practitioners, and healthcare professionals with a nuanced understanding of the current state, challenges, and future prospects of utilizing DDPM in the context of biomedical image segmentation. [ABSTRACT FROM AUTHOR]

In this paper, the finite-time trajectory tracking control problem of a flexible link manipulator (FLM) system with unknown parameters is investigated in joint space. An adaptive nonsingular terminal sliding mode (ANTSM) controller based on an extended state observer (ESO) is proposed to ensure that the tracking error converges to a small neighborhood of zero. Firstly, an adaptive ESO is introduced, which is used to estimate unknown system parameters, including the unknown rigid-flexible coupling coefficient and the unknown control gain. Then, an ESO based on the parameters estimated above is proposed to estimate the unmodeled dynamics and external disturbances of the system in real-time. Finally, an ANTSM controller based on ESO is studied to achieve finite-time trajectory tracking control and vibration suppression without any prior knowledge of system uncertainties and external disturbances. The finite-time convergence ability of the closed-loop system is proved by Lyapunov theory. Experimental results on the Quanser Flexible Link System verify the effectiveness of the proposed controller. [ABSTRACT FROM AUTHOR]

In deep-space optical communication systems, precise pointing and aiming of the laser beam is essential to ensure the stability of the laser link. In this paper, an adaptive compound control system based on adaptive feedforward and Proportional-Integral-Differentiation (PID) feedback is proposed. The feedforward controller is stabilized using Youla-Kucera (YK) parameterization. In the YK parameterized structure, the free parameter Q(z) consists of an adaptive filter. The proposed method constitutes an adaptive feedforward control algorithm through the adaptive filter Q(z). The problem of suppressing laser jitter is transformed into a problem of minimizing a sensitivity function containing the adaptive filter. The stability of the compound control system is ensured by configuring the individual parameters of the YK parameterized feedforward controller and the PID controller, and the adaptive regulation of the controller is realized on the premise of system stability. To verify the effectiveness of the compound control system, we established an experimental platform for laser beam stabilization control. We experimentally compare the effectiveness of the proposed control method with the classical method. The experimental results show that the method proposed in this paper can effectively suppress the complex laser beam jitter consisting of narrow-band sinusoidal and broad-band continuous vibrations.

Fourier ptychographic microscopy (FPM) is a spatial-temporal-modulation high-throughput imaging technique via a sequential angle-varied LED illumination. Therefore, the illuminator is one of the key components and the design of this illuminator is significant. However, because of the property of spherical wave, partial coherence, and aperture-induced vignetting, the acquired images must be processed in blocks first, and rely on parallel reconstruction via a graphics processing unit (GPU). The high cost makes it unappealing compared with commercial whole slide imaging system via a low-cost central processing unit (CPU). Especially, the vignetting severely destroys the space-invariant model and induces obvious artifacts in FPM, which is the most difficult problem. The conventional method is to divide the field of view (FOV) into many tiles and omit those imperfect images, which is crude and may discards low frequency information. In this paper, we reevaluated the conditions of vignetting in FPM. Through our analysis, the maximum side length of FOV is 0.759 mm for a single full-FOV reconstruction via a 4×/0.1 NA objective and a 4 mm spacing LED array in theory, while almost 1.0 mm can be achieved in practice due to the tolerance of algorithm. We found that FPM system can treat the vignetting coefficient Vf below 0.1 as brightfield images and Vf lager than 0.9 as darkfield images, respectively. We reported an optimized distribution for designing an illuminator without vignetting effect according to the off-the-shelf commercial products, which can reconstruct full FOV in one time via a CPU. By adjusting the distribution of LED units, the system could retrieve the object with the side length of FOV up to 3.8 mm for a single full-FOV reconstruction, which achieves the largest FOV that a typical 4×/0.1 NA objective with the field number of 22 mm can afford.

Currently, the on-chip wireless communication system (OWCS) includes 2nd-generation (2G), 3rd-generation (3G), and long-term evolution (LTE) communication subsystems. To improve the power consumption of OWCS, a typical architecture design of system power control unit (SPCU) is given in this paper, which can not only make a 2G, a 3G, and an LTE subsystems enter sleep mode, but it can also wake them up from sleep mode via the interrupt. During the sleep mode period, either the real-time sleep timer or the global system for mobile (GSM) communication sleep timer can be used individually to arouse the corresponding subsystem. Compared to previous sole voltage supplies on the OWCS, a 2G, a 3G, or an LTE subsystem can be independently configured with three different voltages and frequencies in normal work mode. In the meantime, the voltage supply monitor, which is an important part in the SPCU, can significantly guard the voltage of OWCS in real time. Finally, the SPCU may implement dynamic voltage and frequency scaling (DVFS) for a 2G, a 3G, or an LTE subsystem, which is automatically accomplished by the hardware.