![]() by minimizing the total variation (TV) of the desired image for CT image reconstruction from sparse projection views. In 2006, Donoho proposed the concept of compressed sensing (CS) and proved that sparse signals or piecewise images could be satisfactorily reconstructed from far less sampling data than the requirement of the Nyquist sampling theorem.īase on the CS theory, a state of art solution, which is called as adaptive steepest descent projection onto convex sets (ASD-POCS) method 1, was invented by Sidky et al. Specifically, by accommodating measurement statistics, modeling data acquisition geometry, and enforcing physical constraints, regularized iterative reconstruction algorithms often produce superior image quality with highly noisy measurements, and hence having become increasingly popular. Nevertheless, sparse-view CT reconstruction suffers from image quality deterioration caused by the increased streaking artifacts due to missing projections.Ī great effort has been devoted to improve sparse-view CT reconstruction in the past twenty years. Compared to tube current or voltage reduction, sparse-view CT reconstruction does not suffer from the increased noise in projections and has the additional benefit of accelerated scan and projection/back projection calculation. CT reconstruction with this approach is termed sparse-view CT reconstruction in this study. Projection number reduction can be realized by applying sparse-view protocol for a given scanning trajectory. The approach of tube current (or voltage) reduction sacrifices image quality for dose reduction. Basically, low dose CT can be achieved reducing the tube currents (or voltage) or projection numbers. Balancing image quality and x-ray dose level has become a well-known trade-off problem. Despite the rapid developments, image noise and artifacts still remains a major issue in the low dose protocol. As a result, the demand of radiation dose reduction is becoming more and more intense under the principle of ALARA (as low as reasonably achievable). However, with the broadened application of CT in clinical scenarios, the radiation risk issue is receiving more and more attention. Often it's best to contact your provider to verify your connection is good and strong.X-ray Computed Tomography (CT) techniques have been widely utilized in clinical for diagnosis and intervention, including imaging, image-guided needle biopsy, image-guided intervention, and radiotherapy with noticeable benefits. If you're getting artifacts on your TV display and have cable or a satellite connection, make sure you're getting a strong signal.If you're getting artifacts when compressing or changing a video from one format to another, try a different format.If settings are set to their highest quality, and pictures still have artifacts, it's likely a digital camera limitation or issue with the camera. If your digital camera is generating artifacts in pictures, make sure your quality is set to the highest available option.If the same issue persists, make sure you've got the latest video drivers and that the video card is firmly connected into the computer. If your computer monitor is always displaying artifacts, regardless of what program you use, try a different monitor on the computer.Make sure your game is running the latest version and that the video card driver is up-to-date. Artifacts in a video game and often caused by video card driver issues or a video card is getting too hot.Disconnect and re-connections to ensure firmly connected. What to do when getting artifacts?īelow are some general suggestions for troubleshooting artifact-related issues. The picture shows a crashed laptop with digital artifacts. Artifacts can be encountered with a digital camera picture, during the transmission of a digital file, and artifacts created from a signal or data compression. When referring to computers and electronics, artifacts, more commonly known as digital artifacts, are errors that occur during signal transmission or interpretation. ![]()
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