This paper presents a novel method of Iossy image compression for digital colorful image sensors with Bayer color filter arrays （CFAs） based on an analysis of existing compression-first methods. An improved compress...This paper presents a novel method of Iossy image compression for digital colorful image sensors with Bayer color filter arrays （CFAs） based on an analysis of existing compression-first methods. An improved compression and decompression structure is described. The captured CFA raw data are firstly lowpass filtered in RGB space by a smooth filter followed by a down-sampling operation. Next, the data are transformed from RGB space to YCbCr space. Lastly, the filtered data in YCbCr space are compressed directly before full color interpolation to avoid redundancy. The presented method can provide a lower compression ratio and has lower complexity than both conventional interpolation-first image compression methods and other similar existing compression-first methods.展开更多
The collapse of adobe bricks under compressive forces and exposure to water has a duration of several minutes, with only minor displacements before and after the collapse, whence a conceptual question arises: When doe...The collapse of adobe bricks under compressive forces and exposure to water has a duration of several minutes, with only minor displacements before and after the collapse, whence a conceptual question arises: When does the collapse start and when does it end? The paper compares several mathematical models for the description of the fracture process from displacement data. It recommends the use of linear splines to identify the beginning and end of the collapse phase of adobe bricks.展开更多
A dual-beam electronic speckle pattern interferometry (ESPI) system was adopted to get speckle patterns for the measurement of welding dynamic displacement fields. The mathematical model of this system was described, ...A dual-beam electronic speckle pattern interferometry (ESPI) system was adopted to get speckle patterns for the measurement of welding dynamic displacement fields. The mathematical model of this system was described, based on which methods of the ESPI pattern image processing were discussed. Gray transformation and histogram equalization were used to enhance the contrast of speckle patterns. A discrete cosine image processing method was carried out and an exponent low-pass filter was chosen to reduce multiplicative noise in speckle patterns. Speckle grain noise can be eliminated effectively after these processes.展开更多
基金the National Natural Science Foundation of China (Nos. 60372021 and 60475018)
文摘This paper presents a novel method of Iossy image compression for digital colorful image sensors with Bayer color filter arrays （CFAs） based on an analysis of existing compression-first methods. An improved compression and decompression structure is described. The captured CFA raw data are firstly lowpass filtered in RGB space by a smooth filter followed by a down-sampling operation. Next, the data are transformed from RGB space to YCbCr space. Lastly, the filtered data in YCbCr space are compressed directly before full color interpolation to avoid redundancy. The presented method can provide a lower compression ratio and has lower complexity than both conventional interpolation-first image compression methods and other similar existing compression-first methods.
文摘The collapse of adobe bricks under compressive forces and exposure to water has a duration of several minutes, with only minor displacements before and after the collapse, whence a conceptual question arises: When does the collapse start and when does it end? The paper compares several mathematical models for the description of the fracture process from displacement data. It recommends the use of linear splines to identify the beginning and end of the collapse phase of adobe bricks.
文摘A dual-beam electronic speckle pattern interferometry (ESPI) system was adopted to get speckle patterns for the measurement of welding dynamic displacement fields. The mathematical model of this system was described, based on which methods of the ESPI pattern image processing were discussed. Gray transformation and histogram equalization were used to enhance the contrast of speckle patterns. A discrete cosine image processing method was carried out and an exponent low-pass filter was chosen to reduce multiplicative noise in speckle patterns. Speckle grain noise can be eliminated effectively after these processes.
