分析了现场噪音的原因,采用抗性消音、小孔消音的消音原理,设计了一种小孔复合消音降噪装置。从现场布局、设备设计和工艺流程等方面介绍该复合消音降噪装置的应用情况,并对具体使用效果进行评估。降噪筒上均匀布置Φ2 mm小孔,一端封闭...分析了现场噪音的原因,采用抗性消音、小孔消音的消音原理,设计了一种小孔复合消音降噪装置。从现场布局、设备设计和工艺流程等方面介绍该复合消音降噪装置的应用情况,并对具体使用效果进行评估。降噪筒上均匀布置Φ2 mm小孔,一端封闭;当气流经过降噪筒上的小孔时,压力和流速减小,喷气噪声的频率就会移向高频或超高频,明显降低频谱中的可听声成分,从而达到降噪目的,使噪音从110 d B降到80 d B。展开更多
This report deals with introducing two new techniques based on a novel concept of complex brightness gradient in quantitative schlieren images, “inverse process” and “multi-path integration” for image-noise reduct...This report deals with introducing two new techniques based on a novel concept of complex brightness gradient in quantitative schlieren images, “inverse process” and “multi-path integration” for image-noise reduction. Noise in schlieren images affects the projections (density thickness) images of computerized tomography (CT). One spot noise in the schlieren image appears in a line shape in the density thickness image. Noise effect like an infectious disease spreads from a noisy pixel to the next pixel in the direction of single-path integration. On the one hand, the noise in the schlieren image reduces the quality of the image and quantitative analysis and is undesirable;on the other it is unavoidable. Therefore, the importance of proper noise reduction techniques seems essential and tangible. In the present report, a novel technique “multi-path integration” is proposed for noise reduction in projections images of CT. Multi-path integration is required the schlieren brightness gradient in two orthogonal directions. The 20-directional quantitative schlieren optical system presents only images of schlieren brightness in the horizontal gradient and another 20-directional optical system seems necessary to obtain vertical schlieren brightness gradient, simultaneously. Using the “inverse process”, a new technique enables us to obtain vertical schlieren brightness gradient from horizontal experimental data without the necessity of a new optical system and can be used for obtaining any optional directions of schlieren brightness gradient.展开更多
文摘分析了现场噪音的原因,采用抗性消音、小孔消音的消音原理,设计了一种小孔复合消音降噪装置。从现场布局、设备设计和工艺流程等方面介绍该复合消音降噪装置的应用情况,并对具体使用效果进行评估。降噪筒上均匀布置Φ2 mm小孔,一端封闭;当气流经过降噪筒上的小孔时,压力和流速减小,喷气噪声的频率就会移向高频或超高频,明显降低频谱中的可听声成分,从而达到降噪目的,使噪音从110 d B降到80 d B。
文摘This report deals with introducing two new techniques based on a novel concept of complex brightness gradient in quantitative schlieren images, “inverse process” and “multi-path integration” for image-noise reduction. Noise in schlieren images affects the projections (density thickness) images of computerized tomography (CT). One spot noise in the schlieren image appears in a line shape in the density thickness image. Noise effect like an infectious disease spreads from a noisy pixel to the next pixel in the direction of single-path integration. On the one hand, the noise in the schlieren image reduces the quality of the image and quantitative analysis and is undesirable;on the other it is unavoidable. Therefore, the importance of proper noise reduction techniques seems essential and tangible. In the present report, a novel technique “multi-path integration” is proposed for noise reduction in projections images of CT. Multi-path integration is required the schlieren brightness gradient in two orthogonal directions. The 20-directional quantitative schlieren optical system presents only images of schlieren brightness in the horizontal gradient and another 20-directional optical system seems necessary to obtain vertical schlieren brightness gradient, simultaneously. Using the “inverse process”, a new technique enables us to obtain vertical schlieren brightness gradient from horizontal experimental data without the necessity of a new optical system and can be used for obtaining any optional directions of schlieren brightness gradient.
