TDI-CMOS成像系統(tǒng)研究及FPN校正方法設(shè)計(jì)
發(fā)布時(shí)間：2018-11-02 15:02
【摘要】：傳統(tǒng)線陣圖像傳感器采用一維像素陣列結(jié)構(gòu),通過掃描運(yùn)動獲取二維圖像,其成像性能受限于運(yùn)動速度和光照強(qiáng)度。時(shí)間延遲積分(TDI)圖像傳感器采用二維像素陣列結(jié)構(gòu),通過掃描的方式實(shí)現(xiàn)不同行像素對同一景物的多次曝光,等效延長曝光時(shí)間,從而有效提高圖像傳感器的信噪比和靈敏度。TDI-CMOS圖像傳感器具有與CMOS工藝兼容、高集成度、低功耗、抗輻射等優(yōu)點(diǎn),逐漸成為研究熱點(diǎn)。在TDI-CMOS圖像傳感器的研制過程中,對傳感器的功能測試和性能分析是極其重要的一個(gè)環(huán)節(jié)。因此,關(guān)于TDI-CMOS圖像傳感器成像質(zhì)量及其成像系統(tǒng)的研究具有重要意義。為了消除TDI-CMOS圖像傳感器輸出圖像中的固定模式噪聲(FPN),本文首先研究了TDI-CMOS圖像傳感器的工作原理,然后在分析FPN來源、噪聲特點(diǎn)及其對成像質(zhì)量的影響的基礎(chǔ)上,提出了TDI-CMOS圖像傳感器的噪聲模型,并根據(jù)該模型設(shè)計(jì)了一種基于灰度值補(bǔ)償?shù)腇PN校正方法。該方法首先在均勻光下采集大量樣本圖像,然后基于所有樣本圖像的行均值向量和列均值向量分別估計(jì)行FPN和列FPN,最后,通過像素原始灰度值加上對應(yīng)的行FPN估計(jì)值校正行FPN、通過像素原始灰度值減去對應(yīng)的列FPN估計(jì)值校正列FPN。為了驗(yàn)證提出的校正方法的有效性,首先基于128級模擬域累加TDICMOS圖像傳感器設(shè)計(jì)了一套成像系統(tǒng),研究了系統(tǒng)設(shè)計(jì)中的關(guān)鍵技術(shù),具體完成了圖像傳感器硬件電路設(shè)計(jì)、片上可編程系統(tǒng)(SoPC)設(shè)計(jì)及履帶機(jī)械運(yùn)動裝置設(shè)計(jì)。其中,SoPC是成像系統(tǒng)的嵌入式主控系統(tǒng),基于FPGA開發(fā)板設(shè)計(jì)。然后使用設(shè)計(jì)的成像系統(tǒng)采集100幅樣本圖像,并基于MATLAB軟件完成對FPN的估計(jì),最后進(jìn)行FPN校正。實(shí)驗(yàn)結(jié)果表明,使用提出的方法對均勻光照下拍攝的圖像進(jìn)行FPN校正后,其行均值標(biāo)準(zhǔn)差從5.6798 LSB減小到了0.4214 LSB,其列均值標(biāo)準(zhǔn)差從15.2080 LSB減小到了13.4623 LSB;而實(shí)際測試圖像中的行FPN和列FPN也都得到了有效校正。本文設(shè)計(jì)的方法可以有效消除TDI-CMOS圖像傳感器輸出圖像中的FPN。
[Abstract]:The traditional linear image sensor uses one-dimensional pixel array structure to obtain two-dimensional images by scanning motion. Its imaging performance is limited by the speed of motion and the intensity of illumination. The time-delay integral (TDI) image sensor uses two-dimensional pixel array structure to realize multiple exposures of different pixels to the same scene by scanning, which can effectively prolong the exposure time. In order to improve the SNR and sensitivity of the image sensor, TDI-CMOS image sensor has become a hot research area because of its compatibility with CMOS process, high integration, low power consumption, radiation resistance and so on. In the development of TDI-CMOS image sensor, the function test and performance analysis of the sensor is very important. Therefore, it is of great significance to study the imaging quality and imaging system of TDI-CMOS image sensor. In order to eliminate the fixed mode noise in the output image of TDI-CMOS image sensor, this paper first studies the working principle of TDI-CMOS image sensor, then analyzes the source of FPN, the characteristics of noise and its influence on the image quality. The noise model of TDI-CMOS image sensor is proposed and a FPN correction method based on gray value compensation is designed according to the model. Firstly, a large number of sample images are collected under uniform light, and then row FPN and column FPN, are estimated based on row mean vector and column mean vector of all sample images, respectively. Correction row FPN, by pixel original gray value plus corresponding row FPN estimation line FPN, subtractive corresponding column FPN estimate value correction column FPN. In order to verify the validity of the proposed method, an imaging system is designed based on 128-level analog domain accumulative TDICMOS image sensor. The key techniques in the system design are studied, and the hardware circuit of the image sensor is designed. On-chip programmable system (SoPC) design and track mechanical motion device design. Among them, SoPC is the embedded main control system of the imaging system, based on the design of FPGA development board. Then we use the designed imaging system to collect 100 sample images and complete the estimation of FPN based on MATLAB software. Finally, FPN correction is carried out. The experimental results show that the row mean standard deviation decreases from 5.6798 LSB to 0.4214 LSB, and the column mean standard deviation decreases from 15.2080 LSB to 13.4623 LSB; after the proposed method is used for FPN correction of images taken under uniform illumination. The row FPN and column FPN in the actual test image are also corrected effectively. The method designed in this paper can effectively eliminate the FPN. in the output image of TDI-CMOS image sensor.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TP391.41;TP212
本文編號：2306137
[Abstract]:The traditional linear image sensor uses one-dimensional pixel array structure to obtain two-dimensional images by scanning motion. Its imaging performance is limited by the speed of motion and the intensity of illumination. The time-delay integral (TDI) image sensor uses two-dimensional pixel array structure to realize multiple exposures of different pixels to the same scene by scanning, which can effectively prolong the exposure time. In order to improve the SNR and sensitivity of the image sensor, TDI-CMOS image sensor has become a hot research area because of its compatibility with CMOS process, high integration, low power consumption, radiation resistance and so on. In the development of TDI-CMOS image sensor, the function test and performance analysis of the sensor is very important. Therefore, it is of great significance to study the imaging quality and imaging system of TDI-CMOS image sensor. In order to eliminate the fixed mode noise in the output image of TDI-CMOS image sensor, this paper first studies the working principle of TDI-CMOS image sensor, then analyzes the source of FPN, the characteristics of noise and its influence on the image quality. The noise model of TDI-CMOS image sensor is proposed and a FPN correction method based on gray value compensation is designed according to the model. Firstly, a large number of sample images are collected under uniform light, and then row FPN and column FPN, are estimated based on row mean vector and column mean vector of all sample images, respectively. Correction row FPN, by pixel original gray value plus corresponding row FPN estimation line FPN, subtractive corresponding column FPN estimate value correction column FPN. In order to verify the validity of the proposed method, an imaging system is designed based on 128-level analog domain accumulative TDICMOS image sensor. The key techniques in the system design are studied, and the hardware circuit of the image sensor is designed. On-chip programmable system (SoPC) design and track mechanical motion device design. Among them, SoPC is the embedded main control system of the imaging system, based on the design of FPGA development board. Then we use the designed imaging system to collect 100 sample images and complete the estimation of FPN based on MATLAB software. Finally, FPN correction is carried out. The experimental results show that the row mean standard deviation decreases from 5.6798 LSB to 0.4214 LSB, and the column mean standard deviation decreases from 15.2080 LSB to 13.4623 LSB; after the proposed method is used for FPN correction of images taken under uniform illumination. The row FPN and column FPN in the actual test image are also corrected effectively. The method designed in this paper can effectively eliminate the FPN. in the output image of TDI-CMOS image sensor.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：TP391.41;TP212
【參考文獻(xiàn)】
相關(guān)期刊論文 前2條
1 徐超;姚素英;徐江濤;李玲霞;;In-Pixel Charge Addition Scheme Applied in Time-Delay Integration CMOS Image Sensors[J];Transactions of Tianjin University;2013年02期
2 桑美貞;徐江濤;聶凱明;姚素英;;TDI型CMOS圖像傳感器時(shí)序控制設(shè)計(jì)與實(shí)現(xiàn)[J];傳感技術(shù)學(xué)報(bào);2011年12期
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