A dispersion compensation method is introduced to correct the distorted image passing through an ultrathin metal film.An LCD-CCD system is modeled by the back propagation network and used to evaluate the transmittance...A dispersion compensation method is introduced to correct the distorted image passing through an ultrathin metal film.An LCD-CCD system is modeled by the back propagation network and used to evaluate the transmittance of the ultrathin metal film.Training samples for the network come from 729 images captured by shooting test patches,in which the RGB values are uniformity distributed between 0 and 255.The RGB value of the original image that will be distorted by the dispersion is first transformed by mapping from the LCD to the CCD,multiplied by the inverse matrix of the transmittance matrix,and finally transformed by mapping from the CCD to the LCD,then the corrected image is obtained.In order to verify the effectiveness of the proposed method,ultrathin aluminum films with different thicknesses are evaporated on glass substrates and laid between the CCD and LCD.Experimental results show that the proposed method compensates for the dispersion successfully.展开更多
For the narrowband of liner charge-coupled device （CCD） receiver and the imaging rule that cylindrical lens system can compress round facula into narrow and long one, the system is simplified and light force can con...For the narrowband of liner charge-coupled device （CCD） receiver and the imaging rule that cylindrical lens system can compress round facula into narrow and long one, the system is simplified and light force can concentrate on a strip facula, Considered the effective CCD length and selection of lens parameters, the system can be optimized. Correspondingly to the CCD pixels, the ray is composed of much angle information. By widening the parallel ray or increasing the lens aperture, luminous flux can be ensured when oblique incidence. Meanwhile, the effective working range can also be improved. Based on the experimental data, cylindrical system could be applied in accurate angle measurement. It has been proved feasible that the cylindrical system can be used in anchor behavior study for liquid crystal （LC） case. The low-power He-Ne laser cylindrical system can carry out the previous effect in high power laser spherical system.展开更多
The design of vision measurement system of double optical paths with single CCD based on the digital signal processor(DSP) is presented.Using TMS320F2812 as the intelligent control unit,the CCD driving circuit,level c...The design of vision measurement system of double optical paths with single CCD based on the digital signal processor(DSP) is presented.Using TMS320F2812 as the intelligent control unit,the CCD driving circuit,level conversion circuit and CCD output signal data acquisition and processing circuit are designed.By means of plane reflectors,the optical structure of the system is optimized,which reduces errors owing to tilt effect of the measured unit,improves measuring accuracy and makes the system more compact.Double optical paths signal data acquisition with single CCD is demonstrated.In addition,the improved resolution is enhanced up to sub-pixel level by the average polynomial interpolation algorithm.展开更多
A measurement system with the CCD matrix and computer system is designed to test the 2D size of any shape workpieces automatically. In addition, the system adopts the method of the relative measurement which increases...A measurement system with the CCD matrix and computer system is designed to test the 2D size of any shape workpieces automatically. In addition, the system adopts the method of the relative measurement which increases the precision and the velocity.More importantly,the precision cant be changed with the conditions of the temperature and air pressure.The experiments show that the relative precision of 0.002 9 and the absolute precision of 2.97 μm are obtained. The instrument may be used in the product line and make the testing on line possible.展开更多
The basic principle of particle image velocinmetry (PIV) is described. When a PIV image is analyzed by the method of auto-correlation, there is a direction ambiguity of 180 degrees iii velocity measurement. The proble...The basic principle of particle image velocinmetry (PIV) is described. When a PIV image is analyzed by the method of auto-correlation, there is a direction ambiguity of 180 degrees iii velocity measurement. The problem can be solved by using 'Image Shifting Technique', but this makes devices much complicated and difficult to control. A new arrangement of 2-CCD (Charge Coupled Device) fully digitized PIV system, which can also solve the problem successfully, is introduced in the paper. As an example of application of the system, an experimental result of flow field around a horizontal cylinder in wave is presented.展开更多
A system with uniform light reflection in the inner surface within a horizontal 2/3 cylindrical structure for line-scan CCD of the print testing was designed. The design was based on diffuse reflection uniformity of t...A system with uniform light reflection in the inner surface within a horizontal 2/3 cylindrical structure for line-scan CCD of the print testing was designed. The design was based on diffuse reflection uniformity of the integrating sphere and requirement of the strip uniform illumination region. This system was called dome light. White light LED array light sources were used for uniform illumi- nation. The LEDs were filtrated to composite array light source based on coefficient of variation of a single LED. The standard white board and SG color checkers were used in the line-scan CCD imaging experiments under the dome light and ordinary illumination light source. The average color difference （AE） of SG color checkers in CIELAB space was 2. 091 under the dome light and 2. 286 under ordinary illumination light source respectively. Experimental results indicate that the dome light can satisfy illumination uniformity and color rendering consistency for line-scan CCD and provide a standard light source for uniform calibration of different cameras.展开更多
基金Project supported by the National High Technology Research and Development Program of China (Grant No. 2009AA044001)the Open Funds of the State Key Laboratory of Robotics and Systems (HIT),China (Grant No. SKLRS-2010-MS-01)the Fundamental Research Funds for the Central Universities,China
文摘A dispersion compensation method is introduced to correct the distorted image passing through an ultrathin metal film.An LCD-CCD system is modeled by the back propagation network and used to evaluate the transmittance of the ultrathin metal film.Training samples for the network come from 729 images captured by shooting test patches,in which the RGB values are uniformity distributed between 0 and 255.The RGB value of the original image that will be distorted by the dispersion is first transformed by mapping from the LCD to the CCD,multiplied by the inverse matrix of the transmittance matrix,and finally transformed by mapping from the CCD to the LCD,then the corrected image is obtained.In order to verify the effectiveness of the proposed method,ultrathin aluminum films with different thicknesses are evaporated on glass substrates and laid between the CCD and LCD.Experimental results show that the proposed method compensates for the dispersion successfully.
基金This project is supported by Natural Science and Research Foundation ofTsinghua University, China (No.JC2002039).
文摘For the narrowband of liner charge-coupled device （CCD） receiver and the imaging rule that cylindrical lens system can compress round facula into narrow and long one, the system is simplified and light force can concentrate on a strip facula, Considered the effective CCD length and selection of lens parameters, the system can be optimized. Correspondingly to the CCD pixels, the ray is composed of much angle information. By widening the parallel ray or increasing the lens aperture, luminous flux can be ensured when oblique incidence. Meanwhile, the effective working range can also be improved. Based on the experimental data, cylindrical system could be applied in accurate angle measurement. It has been proved feasible that the cylindrical system can be used in anchor behavior study for liquid crystal （LC） case. The low-power He-Ne laser cylindrical system can carry out the previous effect in high power laser spherical system.
基金supported by the Program of Tianjin Science and Technology Plan (No.08ZHTGCG01100)
文摘The design of vision measurement system of double optical paths with single CCD based on the digital signal processor(DSP) is presented.Using TMS320F2812 as the intelligent control unit,the CCD driving circuit,level conversion circuit and CCD output signal data acquisition and processing circuit are designed.By means of plane reflectors,the optical structure of the system is optimized,which reduces errors owing to tilt effect of the measured unit,improves measuring accuracy and makes the system more compact.Double optical paths signal data acquisition with single CCD is demonstrated.In addition,the improved resolution is enhanced up to sub-pixel level by the average polynomial interpolation algorithm.
文摘A measurement system with the CCD matrix and computer system is designed to test the 2D size of any shape workpieces automatically. In addition, the system adopts the method of the relative measurement which increases the precision and the velocity.More importantly,the precision cant be changed with the conditions of the temperature and air pressure.The experiments show that the relative precision of 0.002 9 and the absolute precision of 2.97 μm are obtained. The instrument may be used in the product line and make the testing on line possible.
基金This Project was financially supported by the National Science Foundation of China and British Council
文摘The basic principle of particle image velocinmetry (PIV) is described. When a PIV image is analyzed by the method of auto-correlation, there is a direction ambiguity of 180 degrees iii velocity measurement. The problem can be solved by using 'Image Shifting Technique', but this makes devices much complicated and difficult to control. A new arrangement of 2-CCD (Charge Coupled Device) fully digitized PIV system, which can also solve the problem successfully, is introduced in the paper. As an example of application of the system, an experimental result of flow field around a horizontal cylinder in wave is presented.
基金Supported by the National Natural Science Foundation of China(61078048)
文摘A system with uniform light reflection in the inner surface within a horizontal 2/3 cylindrical structure for line-scan CCD of the print testing was designed. The design was based on diffuse reflection uniformity of the integrating sphere and requirement of the strip uniform illumination region. This system was called dome light. White light LED array light sources were used for uniform illumi- nation. The LEDs were filtrated to composite array light source based on coefficient of variation of a single LED. The standard white board and SG color checkers were used in the line-scan CCD imaging experiments under the dome light and ordinary illumination light source. The average color difference （AE） of SG color checkers in CIELAB space was 2. 091 under the dome light and 2. 286 under ordinary illumination light source respectively. Experimental results indicate that the dome light can satisfy illumination uniformity and color rendering consistency for line-scan CCD and provide a standard light source for uniform calibration of different cameras.
