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1.
Cureus ; 15(5): e38507, 2023 May.
Article in English | MEDLINE | ID: mdl-37284386

ABSTRACT

Angiosarcoma is a rare soft tissue sarcoma originating from endothelial cells. It can occur anywhere when there is a blood vessel or lymphatic channel, making highly perfused cutaneous sites their usual location, though they can also develop within visceral structures. Pulmonary angiosarcoma is usually caused by metastasis from other primary sites. The clinical course of pulmonary angiosarcoma is very aggressive, and the prognosis is poor. We present a case of a 55-year-old man who presented to the hospital with progressive exertional dyspnea and right-sided pleuritic chest pain for the past few days. He was found to have recurrent anemia and acute kidney injury. His hospital course was complicated by the development of hypoxia and hemoptysis. Computed tomography of the chest without contrast revealed bilateral nodular, ground-glass opacities compatible with diffuse alveolar hemorrhage. Further investigation with a lung biopsy revealed epithelioid angiosarcoma with extensive microvascular tumor emboli and invasive pulmonary aspergillosis (Aspergillus fumigatus) with patchy necrotizing pneumonia. He later developed acute hypoxic respiratory failure and worsening kidney failure, so he was transferred to the intensive care unit. Upon discussing with the family, the patient was put on comfort measures, and he passed away the following day. We present a rare presentation of concurrence of pulmonary angiosarcoma and invasive aspergillosis. Upon searching the literature, our case is one of the first to report such concurrence. Because of its rarity, the non-specific clinical presentation makes the diagnosis challenging.

2.
IEEE Trans Image Process ; 23(8): 3352-67, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24956363

ABSTRACT

Streaming mobile augmented reality applications require both real-time recognition and tracking of objects of interest in a video sequence. Typically, local features are calculated from the gradients of a canonical patch around a keypoint in individual video frames. In this paper, we propose a temporally coherent keypoint detector and design efficient interframe predictive coding techniques for canonical patches, feature descriptors, and keypoint locations. In the proposed system, we strive to transmit each patch or its equivalent feature descriptor with as few bits as possible by modifying a previously transmitted patch or descriptor. Our solution enables server-based mobile augmented reality where a continuous stream of salient information, sufficient for image-based retrieval, and object localization, is sent at a bit-rate that is practical for today's wireless links and less than one-tenth of the bit-rate needed to stream the compressed video to the server.


Subject(s)
Data Compression/methods , Image Interpretation, Computer-Assisted/methods , Imaging, Three-Dimensional/methods , Photography/methods , User-Computer Interface , Video Recording/methods , Algorithms , Image Enhancement/methods , Online Systems , Sensitivity and Specificity , Signal Processing, Computer-Assisted
3.
IEEE Trans Image Process ; 19(7): 1740-55, 2010 Jul.
Article in English | MEDLINE | ID: mdl-20215074

ABSTRACT

The direction-adaptive partitioned block transform (DA-PBT) is proposed to exploit the directional features in color images to improve coding performance. Depending on the directionality in an image block, the transform either selects one of the eight directional modes or falls back to the nondirectional mode equivalent to the conventional 2-D DCT. The selection of a directional mode determines the transform direction that provides directional basis functions, the block partitioning that spatially confines the high-frequency energy, the scanning order that arranges the transform coefficients into a 1-D sequence for efficient entropy coding, and the quantization matrix optimized for visual quality. The DA-PBT can be incorporated into image coding using a rate-distortion optimized framework for direction selection, and can therefore be viewed as a generalization of variable blocksize transforms with the inclusion of directional transforms and nonrectangular partitions. As a block transform, it can naturally be combined with block-based intra or inter prediction to exploit the directionality remaining in the residual. Experimental results show that the proposed DA-PBT outperforms the 2-D DCT by more than 2 dB for test images with directional features. It also greatly reduces the ringing and checkerboard artifacts typically observed around directional features in images. The DA-PBT also consistently outperforms a previously proposed directional DCT. When combined with directional prediction, gains are less than additive, as similar signal properties are exploited by the prediction and the transform. For hybrid video coding, significant gains are shown for intra coding, but not for encoding the residual after accurate motion-compensated prediction.

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