An Adaptive Rate Blocked Compressive Sensing Method for Video

An adaptive rate Compressive Sensing (CS) method for video signals is proposed. The Blocked Compressive Sensing (BCS) scheme is adopted in this method. Firstly, each video frame is blocked and measured by the BCS scheme, and then the mean and variance of each image block are estimated by observing the CS measurement results. Using the mean and variance of each image block, the sparsity of the block is estimated and then the block can be classified. Adaptive rate sampling is realized by assigning different sampling rates to different classes. At the same time, in order to make better use of the correlation between video frames, a reference block subtraction method is also designed in this paper, which uses the estimates of the sparsity of image blocks as the basis for the reference block update. All operations of the proposed method only depend on the CS measurement results of image blocks and all calculations are simple. Thus, the proposed method is suitable for implementation in CS sampling devices with limited computational performance. Experiment results show that, compared with the actual values, the sparsity estimates and block classification results of the proposed method are accurate. Compared with the latest adaptive Compressive Video Sensing methods, the reconstructed image quality of the proposed method is better.

Design of fully automatic calibration machine for reference block based on machine vision

In order to solve the problems of the existing standard Brinell hardness machine such as low automation, the time-consuming indentation measurement and the human influence in indentation measurement, a calibration machine for reference block was designed. It shows that this machine can reduce the influence of the temperature difference between the hardness block and the measurement platform; it eliminates the time for the indentation measuring system to find the indentation and juxtapose it with the centre of the field of view and implements fully Brinell hardness automatic calibration.

Research on dispersion in indenter and reference block for Rockwell hardness test

In this report, the Rockwell indenters and hardness reference blocks obtained from different three manufacturers were evaluated. And these results with the tolerances for the indirect verification prescribed in ISO 6508-2 and ASTM E18 were compared, it has been suggested that the tolerances prescribed in ASTM E18 might be too strict in view of actual circumstances.

Equivalent Sensitivity Setting During Ultrasonic Inspection of Steel Butt Welded Joints

Introduction. The echo-pulse technique is commonly used for welded joints ultrasonic testing. The first step of the technique is setting the ultrasonic flaw detector sensitivity. For this purpose NDT-operators usually use calibration blocks with a flat cylindrical or hemispherical reflectors, which are to be manufactured and metrologically certified for every weld joint size and transducer angle. The objective of this work was to develop a sensitivity setting technique using the CO-2 reference block, which could take into account the equivivalent area of the flat cilindrical reflector (as a model of a point-planar flaw) and the equivivalent area of the hemispherical reflector (as a model of a point-bulk flaw). Method. The paper analyzes methods of ultrasonic flaw detector sensitivity setting while testing of butt welded joints with the use of samples and reference reflectors of different types. The theoretical studies using beam acoustics and the Kirchhoff method, were carried out. Results. The analytical dependences for calculation of the sensitivity correction factors have been presented for the equivalent sensitivity setting on a side cylindrical reflector of 6 mm in diameter with the center line location at a depth of 15 mm within the CO-2 reference block. For automation of calculations the NDTRT-20.01 software has been developed and implemented. The sensitivity setting procedures with the use of the NDTRT-20.01 software and without it are given. Discussion. The offered technique has the following advantages: for different thicknesses of welded sheets with different requirements to the minimum acceptable defect the only CO-2 reference block is needed; the sensitivity can be adjusted on both the flat cilindrical reflector and the hemispherical reflector; the NDTRT-20.01 software allows automating the calculations of sensitivity correction factors and flaw detector sweep parameters.

Measurement of glacier velocity at Pik Lenin, Tajikistan, by feature tracking

Glaciers, especially in mountain area are sensitive indicators of climate fluctuations and also contribute to present rates of sea level rise. In Central Asia, these glaciers are the primary resource for fresh water. Understanding the seasonal behavior of these glaciers would help to make efficient use of the available water reservoir. Different methods have been employed to study glacier displacements in past. The conventional survey techniques are very cost-intensive and highly depend on accessibility to high mountain glaciers also directs us to look for new ways to study these areas. Here remote sensing comes in handy with freely available data and a good coverage with high spatial and temporal resolution. Optical satellite imagery, available free can be effectively used for research purpose. The glacier in this region fed lake Karakul (380 km²), the largest Lake in Tajikistan. The objective is to study the displacement tendency of the Glacier in Pik Lenin area using Landsat 7 dataset. Normalized cross correlation algorithm has been implemented via CIAS to estimate the motion of glacier surface. A number of combination of reference block and search area size were tested for 30 m resolution dataset. As a result the specifications: reference block size of 15 pixels and search area size of 10 pixels was found out as the best set of parameters and considered for further processing. The study derives a reliable set of data depicting the velocities in the glacier which after post processing shows peak velocity of 121 m/y of the glacier.