Chengdu Holdtecs Co Ltd

Chengdu, China

Chengdu Holdtecs Co Ltd

Chengdu, China
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Su Y.,University of Electronic Science and Technology of China | Su Y.,CAS Chengdu Institute of Optics and Electronics | Yutang Y.,Chengdu Holdtecs Co Ltd | Yu X.,Chengdu Holdtecs Co Ltd | And 4 more authors.
Circuit World | Year: 2014

Purpose This paper aims to solve the issue of target positioning in auto stiffener bonder (ASB) systems for flexible printed circuits. Design/methodology/approach The proposed approach uses Phong's bidirectional reflectance distribution function (BRDF) model to simulate the reflection of light off a target in ASB systems to predict the current pose of the target based on image brightness, update the template, decrease the initial errors in the template and narrow down the search range. Findings The experimental results indicate that the proposed approach can predict the inclination angle of the target with precision, presenting angle prediction errors of less than three degrees. Furthermore, with larger inclined angles, the overall matching errors were less than 1.5 pixels. Comparisons with the unmodified matching algorithm revealed that the proposed approach resulted in 65 per cent less calculation time for the algorithm and 14 per cent higher overall work efficiency in the ASB system. Originality/value The edge-based perspective shape matching algorithm was modified using the Phong BRDF model and enhanced algorithm efficiency with the target pose prediction method while ensuring the precision and robustness of the system. The proposed approach has high potential value and can be expanded to recognition systems for objects with varying inclination angles and highly reflective surfaces.. © Ke Ren, 2014.


Luo Y.,University of Electronic Science and Technology of China | Zhang T.,University of Electronic Science and Technology of China | Zhang T.,Chengdu HOLDTECS Co. | Liu L.,University of Electronic Science and Technology of China | And 3 more authors.
Jiliang Xuebao/Acta Metrologica Sinica | Year: 2016

A JPEG image compression method based on FPGA and DDR II is proposed. The A3 high-speed scanner is designed and realized. The issue of mutual restraint between the hardware resource and the scanning speed in the high-speed scanner is solved. Basic principle is to build flexible, fast large amount of data storage and transmission mode while reducing the consumption of on-chip RAM through the internal and external storage type water reuse model. And using an efficient time-multiplexed data link to implement the JPEG image compression further improves the compression and transmission speed of hardware module. Theoretical analysis and experimental results show that using the A3 high-speed scanner designed with low-end FPGA chip, the speed of scanning A3 wide paper under a 300 dpi resolution can reach 140 page per minute, scanning time delay is less than 1 ms, peak signal noise ratio as high as 86.9 dB before and after compression, and this fully meets the requirements of high-end high-speed scanners. The high-speed scanners for hardware resource requirements are greatly reduced under the implementation of the model, and this model can also be promoted to apply in other high-speed scanner with different format. © 2016, Acta Metrologica Sinica Press. All right reserved.


Song Y.-C.,University of Electronic Science and Technology of China | Chen Z.-L.,University of Electronic Science and Technology of China | Luo Y.,University of Electronic Science and Technology of China | Liu L.,University of Electronic Science and Technology of China | And 5 more authors.
Jiliang Xuebao/Acta Metrologica Sinica | Year: 2015

A multidirectional projection method which can count the number of seals on bundled banknotes automatically and quickly is introduced. The fundamental principle of this method is that, based on the theory of image processing, converting bundled banknotes image from RGB space to LUV space in the first, processing it by using cluster analysis algorithm, then a binary image of the tied note can be gained. Using thought of multidirectional projection, projection transformation in the vertical direction and the horizontal direction then be applied to in turn. Finally the number of the seals can be counted. Theoretical analysis and the experimental results show that, this method can remove the impact of background noise effectively, do not depend on the quality of seals sigil, and improve the efficiency and accuracy of the automatical number statistics of the seals. ©, 2015, Chinese Society for Measurement. All right reserved.


Song Y.,University of Electronic Science and Technology of China | Song Y.,Chengdu Holdtecs Co. | Chen W.,University of Electronic Science and Technology of China | Chen W.,Chengdu Holdtecs Co. | And 8 more authors.
Guangxue Xuebao/Acta Optica Sinica | Year: 2014

Focused on the problems that it's difficult to obtain high precision mosaic image of object having duplicate texture in the automatic visual inspection system, a new two-dimensional (2D) image mosaic method based on sub-pixel grating positioning is presented. The method uses grating to record positions of object and calibration plate to accurately calibrate angles of X and Y axes between platform and camera, and build a 2D stitching model based on global Cartesian coordinate system to complete image stitching. Experimental results show that the method's calibration repeatability reaches 10-4 rad order of magnitude, with average physical error of 8 mm, and stitching precision increases nearly 8 times than that of not correction, 2 times better than the method that has been reported. The method has been successfully used in the online automatic inspection equipment for ceramic substrate of navigation satellite's receiving antenna circuit. The research result can be widely applied in machine vision automated inspection fields that require sub-pixel level detection precision.


Luo Y.,University of Electronic Science and Technology of China | Guo T.,University of Electronic Science and Technology of China | Guo T.,Chengdu HOLDTECS Co. | Liu L.,University of Electronic Science and Technology of China | And 5 more authors.
Jiliang Xuebao/Acta Metrologica Sinica | Year: 2016

A real-time one-way scanning edge detection on a field programming gate array with dual-core digital signal processor platform is proposed to meet the high image processing speed needs of 900 paper currency per minute in class A currency counting machine. Real-time one-way scanning edge detection is used instead of usual 4-way scanning edge detection, and the field programming gate array is used to combine the encoding process of one-dimensional edge information with the process of image acquisition. With the dual-core digital signal processor the edge information can be processed in parallel. And so, the efficiency of the edge detection could be improved greatly. The experimental results show the new method can shorten the tens of milliseconds with the 4-way paper currency edge scanning method to microsecond level. The detection efficiency is increased to 50.5 times of the 4-way scanning edge detection method. © 2016, Acta Metrologica Sinica Press. All right reserved.


Luo Y.,University of Electronic Science and Technology of China | Tang X.,University of Electronic Science and Technology of China | Yang J.,University of Electronic Science and Technology of China | Liu L.,University of Electronic Science and Technology of China | And 7 more authors.
Qiangjiguang Yu Lizishu/High Power Laser and Particle Beams | Year: 2014

A new non-uniformity correction method used in contact image sensor (CIS) scanner is presented, and it could rapidly and efficiently accomplish non-uniformity correction of CIS scanner's color image and eliminate the color difference of CIS. To obtain uniform color images, the multi-point segmented one-step method is adopted in calibration process and FPGA is used for correcting. For the resolution of CIS scanner up to 1200 dpi, pattern paper is only captured once to complete the calibration of all color space and correction is accomplished during the acquiring image process, and it takes only 0.125 microsecond. The practical application results show that the output image's uniformity is about ten times promotion than that before correction and about three times than that with traditional two-point method.


Luo Y.,University of Electronic Science and Technology of China | Tan P.-Y.,University of Electronic Science and Technology of China | Tan P.-Y.,Chengdu HOLDTECS Co. | Liu L.,University of Electronic Science and Technology of China | And 2 more authors.
Guangxue Jingmi Gongcheng/Optics and Precision Engineering | Year: 2014

As the frequency changing of external trigger signal from an external trigger Contact Image Sensor( CIS) camera will cause the nonuniform of a scanned image gray value, a new exposure method-two-trigger method was proposed. First, the reason that the frequency changing of external trigger signal affects the image gray value was analyzed. Then, the two-trigger method was introduced. With the method, an external trigger signal was converted to two trigger signals, the first one was used to control the exposure and the second one was used to control the CIS to output data. Finally, it explained that the method can improve the image quality theoretically. A 1.6 meter non-distortion long-term array CIS camera was fabricated based on this method. The experimental results show that the fluctuation range of scanned image gray value is reduced by 75%, and the horizontal stripes on the image is eliminated at different trigger frequencies. When it is applied to an intelligent vision stitch digital printing machine, the image of 1 mm×1 mm hole in the embroidered cloth is clear. It concludes that the proposed method reduces the effect of the frequency changing of external trigger signal on images effectively and improves the image quality successfully.

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