Search

With the application of stitching technology in CMOS image sensors of large arrays, the traditional clock tree synchronization design method is not suitable for the two-side drive circuit of pixel arrays, resulting in the serious problems of DC penetration and bad row of the two-side drive of pixel arrays in the same row. In this paper, in terms of the idea of self-adaptive correction on chip, a consistency driving method which can be applied to stitching pixel arrays is proposed. The method can be adapted to the change of chip working environment, and has the characteristics of simple structure and high reliability. Based on 55 nm technology, the present method is applied and verified in a large array CMOS image sensor with 150M pixel size and 77 mm×84 mm chip area of 12 288×12 288. The experimental results show that, under a master clock of 500 MHz and a row clock of 125 kHz, the inconsistency of bilateral row drive is reduced from 17.5 ns to less than 2 ns (one clock period), and the consistency is improved by above than 9 times, ensuring that the frame frequency of the super-array image sensor with a scale of 100 million pixels can reach more than 10 frames.

CMOS image sensor (CIS) cameras are common imaging devices, compared with charge coupled device (CCD), CIS has unique advantages such as small size, high integration, low power consumption and lightweight. In the process of monitoring in the nuclear industry environment, the CIS and camera motherboard are vulnerable to noise caused by gamma radiation, which can affect the imaging resolution of the image. Therefore, it is necessary to evaluate the anti�radiation ability of CIS camera from a systematic perspective and analyze different test methods of camera resolution after irradiation. By using 60Co�γ radiation source to irradiate CIS camera, the irradiated CIS camera was combined with irradiated mainboard and unirradiated mainboard to form different cameras, and the two kinds of cameras were tested. The following data can be obtained from camera tests, such as, the relationship between dark current and cumulative dose of CIS after irradiation, the relationship between resolution value and cumulative dose under different test methods based on ISO 12233 standard, the relationship between the number of noise points in the minimum gray value area and the maximum gray value area of the target area of the test card image collected by the camera, the relationship between the average number of noise points in the whole target area and the cumulative dose, and the relationship between the gray value of the resolution test card and the cumulative dose. The functional relationship between noise and modulation transfer function (MTF) of the irradiated imaging system was established through the theoretical derivation of MTF, by putting the gray values of the resolution test card under different cumulative doses into formulas to obtain the functional relationship between the radiation dose of the calculated MTF value. Finally, by analyzing the theoretical calculation and the actual measurement of MTF value, the functional relationship between noise and image resolution and radiation dose of the typical CIS camera was obtained, and then the upper limit of radiation dose of the CIS camera under the corresponding resolution was obtained. The results show that both CIS noise and camera motherboard noise have an impact on camera resolution, and the noise increases with the increase of cumulative dose. The total ionization dose of the camera is less than 150 krad(Si), camera resolution is not decrease significantly. In ISO 12233 eSFR resolution test, it is found that it is more reasonable to evaluate the resolution parameters of the irradiated camera by using aliasing onset based on the wedge pattern test than the SFR test method.

The conventional high-resolution optical microscopy for biomedical imaging has high cost and low portability due to bulky optical lenses system.To realize miniaturized imaging,the recent advance of lensless microfluidic on-chip imaging technique based on the integration of CMOS image sensor and microfluidics has provided one promising solution.Therefore,the architecture,principle,problems and improvement solutions for different miniaturized lensless microfluidic on-chip bio-imaging,including shadow imaging,holographic imaging,fluorescent imaging and color imaging were reviewed.And the deficiencies and possible development directions were discussed.

In order to solve the problem of noise preprocessing in the process of image acquisition by complementary metal oxide semiconductor(CMOS) image sensor, a configurable adaptive weighted mean filter module in FPGA is proposed. This module determines the direction of the texture by detecting the variance of different directions in the filter window, thus automatically generating the corresponding weighting coefficients. The weighted mean filter can process image with a width of no more than 4 094 pixels, so as to achieve the goal of de-noising and preserving edges. Finally, the experiment shows that when the image width is 2 048, the delay is 42.04 μs, and it satisfies the real-time requirement. The image noise is obviously reduced. The texture edge burr is disappearing, and the image quality can be improved better after filtering.

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In order to overcome the problems of low and non-adjustable resolution existing in wireless images sensor nodes applied in agricultural images acquisition at present, a wireless image sensor node with real-time adjustable resolution was designed and realized in this paper. The node was composed of an image acquisition module, a processor module, a wireless communication module and a power module. The node needed to not only capture, compress, and transmit image data, but also perform multiple task schedules and network protocols, so a powerful ARM (advanced RISC machines) processor S3C6410 was chosen as the processor module of the node. Considering the cost and power consumption, a CMOS (complementary metal oxide semiconductor) type image sensor chip was chosen to design the image acquisition module of the node. The design of image acquisition module included image sensor PCB (printed circuit board) design, chip pin interface design, appropriate lens selection, and development of the sensor chip driver. In order to monitor a larger area of the crop and remotely transmit crop images, the node integrated a WiFi (wireless fidelity) or 4G (the 4th generation) module. A solar power supply system was designed to make the node work stably in the field for a long time. To ensure the stability and reliability of the node, the powerful embedded Linux operating system was employed as the software development platform, and a modular designing method was adopted to program the software system of the node in C/C++ language based on this platform. In order to realize real-time adjustment of the resolution, an algorithm of resolution real-time adjustment based on driver layer and application layer collaboration and multi-thread concurrence was proposed, and all the functions of resolution real-time adjustment of image acquisition, image compression and image transmission were realized in the application layer of software system. In order to verify the performance of the node designed, a series of tests were conducted in Cencun experimental base of South China Agricultural University and Guangdong Dongsheng Farm (Panyu) from April to September in 2016. In the tests, 7 nodes were deployed in the farmland to form an acquisition and transmission network based on WiFi and 4G technologies. To ensure the nodes work stably in the field, where the climate was changeable and the infrastructure was absent, the nodes were encapsulated in a waterproof spherical shield, and a solar panel plus rechargeable batteries was used to supply power for them. The nodes were tested from the aspects of multi-resolution capability, real-time adjustment capability, image acquisition and transmission performance (transmission time and packet loss rate), and the availability of node energy. The test results indicated that the node had 7 different resolutions and its highest resolution was up to a pixel of 5 M, and more importantly, it could adjust its resolution in real time under the control of a remote user, then capture images with different resolution, and finally transmit them to the remote server. The time consumed to capture, compress and transmit 4 images with different resolution of 640×480, 1280×1024, 2048×1536, and 2592×1944 was 4.67, 8.77, 15.38 and 22.74 s respectively, and the average transmission packet loss ratio of 4 images was less than 1%. The tests validate the node designed in this work can capture crop images with different resolution in real time and transmit them remotely, and satisfy the requirement of different users for different crop image precision. [ABSTRACT FROM AUTHOR]

The miniature cameras are the critical equipments to support the low-cost Micro Air Vehi cles or small satellites for earth observation and many other applications. So a miniature imaging system with high resolution and large area array was proposed in this paper. Firstly, the target sampling distance and swath width were estimated for the designed imaging system. Then the electronic scheme of the system was described, where the working principle of the key chip OV14825 was introduced, and the software design based on FPGA was analyzed for serial differential data receiving and forwarding. Finally, imaging experiments were carried on the designed camera. The resolution was better than 0.5 mm when imaging in the 13 m distance, and the obtained images were rich in details, which proved that the scheme was feasible. And the miniature cameras with high resolution and large area array were of great value. [ABSTRACT FROM AUTHOR]

In order to satisfy the requests of the high frame rate and high resolution of fast moving scene in national defense, research and industry, a camera with high-speed and high resolution was de veloped. The functions and characteristics of CMOS image sensor AM41V4 which can cover the requests were introduced, a camera system based on the image sensor was designed. The FPGA was used as the core to control the system timing and DDR solid storage was embedded as the imaging memory in the camera system. Consequently, a flexible working pattern according to specific requirements of the test shoot occasions was realized. The frame rate of the system is 1 000 frames per second, when the resolution of the image is 1 920 pixel x 1 080 pixel. Besides, the camera system reaches a real-time monitoring function. The system has the advantages of high shooting speed, clear image, high performance and flexibility. It has great value for fast capture and shooting record of high-speed moving targets. [ABSTRACT FROM AUTHOR]

The paper proposes a project of drive circuit of real-time image capturing and displaying based on FPGA. The OmniVision's 0V7670 is chosen as CMOS image sensor, while Altera's Cyclone II series EP2C8Q208C8N as the logic control chip. The drive circuit has been verified by Modelsim. The simulation results show that the system meets the requirements of timing and stable image output perfectly. [ABSTRACT FROM AUTHOR]

This paper introduces a kind of immune colloidal gold detector instrument from the aspects of machinery,hardware and software.The instrument first collects one image through a CMOS sensor and then analyzes the image with image processing algorithm on Linux platform.Firstly,the instrument sets and stores the parameters separately for each test item,and then calls the saved item parameters when testing the item sample.So,the instrument can be used in a variety of fields and items.In this paper,a quantitative experimental test on C-reactive protein sample was performed,and the results indicate the coefficient of determination what denoted R 2 equal to 0.99,and the repeatability is greater than 93%.