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  • Foto del escritorCarlos Osorio


Search and rescue missions are critical in saving lives and minimizing the damage caused by natural disasters, accidents, and other emergencies. While helicopters and manned aircraft have traditionally been used for search and rescue operations, the cost of operating these vehicles can be prohibitive. SAR drones, on the other hand, offer a more cost-effective solution for search and rescue missions.


One type of SAR drone that has gained popularity in recent years is the GSM-rescue drone. These drones use the Global System for Mobile Communications (GSM) network to locate missing persons in emergency situations. The GSM-rescue drones are equipped with a special GSM receiver that can detect signals from mobile phones within a certain radius, allowing rescuers to pinpoint the location of missing persons.


In addition to their ability to locate missing persons, SAR drones are also ideal for identifying potential hazards in the search area. By providing a bird's-eye view of the search area, SAR drones can help identify obstacles, dangerous terrain, and other hazards that may pose a threat to rescuers.

There are several types of SAR drone platforms, each with its advantages and disadvantages. Fixed-wing SAR drones, for example, are faster and can operate at higher altitudes, making them ideal for covering large search areas quickly. However, they have limited maneuverability and may not be able to fly in tight spaces.


On the other hand, multirotor UAVs and unmanned helicopters are more maneuverable and can hover in place to provide a stable imaging platform. This makes them ideal for search and rescue missions in tight spaces or areas with obstacles. They can also take off and land vertically, making them more versatile in terms of deployment.


Hybrid VTOL SAR drones, which combine the advantages of fixed-wing and multirotor UAVs, are also becoming increasingly popular. These drones can take off vertically, like a multirotor UAV, and then transition to forward flight, like a fixed-wing UAV. This gives them the operational footprint advantages of a multirotor drone and the extended range and coverage of a fixed-wing drone, making them ideal for search and rescue missions in a variety of environments.


SAR drones have proven to be an efficient and effective tool in search and rescue missions. They provide first responders with quick deployment, stable imaging capabilities, and an option to operate in hazardous environments without risking human lives. With different types of drones available, search and rescue teams can choose the most appropriate drone for the mission, based on the environment and resources available. The future of SAR drones looks promising, with advancements in technology leading to even more efficient and effective drone platforms.

  • Foto del escritorCarlos Osorio

Actualizado: 18 abr 2023

Phase retrieval is an important problem in many fields, including image processing, optics, and computer vision. It refers to the process of recovering the phase of a signal from its magnitude. In recent years, deep learning has emerged as a powerful tool for image processing tasks, including phase retrieval. In this article, we will explore the concept of phase retrieval in image processing and discuss the use of untrained deep learning models for phase retrieval.



Phase Retrieval in Image Processing


In image processing, phase retrieval refers to the process of reconstructing an image from its magnitude. The magnitude of an image is the absolute value of its Fourier transform, while the phase is the angle of the Fourier transform. Phase retrieval is necessary in many applications where only the magnitude of the image can be measured. For example, in X-ray crystallography, the intensity of the X-ray diffraction pattern can be measured, but the phase information is lost. Similarly, in microscopy, the phase information of an image is often lost due to the use of lenses. Phase retrieval can be approached using various algorithms, including the Gerchberg-Saxton algorithm, the Fienup algorithm, and the alternating projection algorithm. These algorithms typically require prior knowledge of the phase or some initial estimate of the phase. However, in some cases, this prior knowledge may not be available or may be inaccurate, making the phase retrieval problem challenging.


Untrained Deep Learning for Phase Retrieval


Deep learning has been successfully applied to various image processing tasks, including image restoration, denoising, and segmentation. Recently, deep learning has also been applied to phase retrieval. One approach is to use untrained deep learning models for phase retrieval. These models are trained on a large dataset of random phase images and their magnitudes. During inference, the model is presented with the magnitude of an image and is expected to output the phase. The use of untrained deep learning models for phase retrieval has several advantages. First, it eliminates the need for prior knowledge of the phase or some initial estimate of the phase. Second, it can handle noise and other distortions in the input magnitude. Third, it can be trained on a large dataset of random phase images, making it applicable to a wide range of problems. One popular untrained deep learning model for phase retrieval is the U-Net. The U-Net is a convolutional neural network that has been widely used for image segmentation tasks. However, it can also be used for phase retrieval by treating the magnitude of an image as the input and the phase as the output. The U-Net architecture consists of a contracting path, which encodes the input image into a latent space, and an expanding path, which decodes the latent space into the output phase.


Phase retrieval is an important problem in image processing, and deep learning has emerged as a powerful tool for addressing this problem. Untrained deep learning models, such as the U-Net, have been shown to be effective for phase retrieval, eliminating the need for prior knowledge of the phase or some initial estimate of the phase. The use of untrained deep learning models for phase retrieval has the potential to revolutionize the field of image processing, making it applicable to a wide range of problems.

 

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