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Investigation of Color Aliasing of High Spatial Frequencies and Edges for BayerPattern Sensors and Foveon X3 ® Direct Image Sensors
"... The reproduction of an edge and a high frequency bar pattern is examined for image sensors employing two different color sampling technologies: Bayer RGB color filter array, and Foveon X3 solid state full color. Simulations correlate well with actual images captured using sensors representing both t ..."
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Cited by 2 (0 self)
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The reproduction of an edge and a high frequency bar pattern is examined for image sensors employing two different color sampling technologies: Bayer RGB color filter array, and Foveon X3 solid state full color. Simulations correlate well with actual images captured using sensors representing both technologies. Color aliasing artifacts in the Bayer mosaic case depend on whether an antialiasing optical lowpass filter is used, and are severe without such a filter. For both the edge image and the bar pattern, the Foveon X3 direct image sensor generates few or no color aliasing artifacts associated with sampling.
Cmos Image Sensors Dynamic Range and SNR Enhancement via Statistical Signal Processing
"... Most of today's video and digital cameras use CCD image sensors, where the electric charge collected by the photodetector array during exposure time is serially shifted out of the sensor chip resulting in slow readout speed and high power consumption. Recently developed CMOS image sensors, by compar ..."
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Cited by 1 (1 self)
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Most of today's video and digital cameras use CCD image sensors, where the electric charge collected by the photodetector array during exposure time is serially shifted out of the sensor chip resulting in slow readout speed and high power consumption. Recently developed CMOS image sensors, by comparison, are read out nondestructively and in a manner similar to a digital memory and can thus be operated at very high frame rates. A CMOS image sensor can also be integrated with other camera functions on the same chip ultimately leading to a singlechip digital camera with very compact size, low power consumption and additional functionality. CMOS image sensors, however, generally su#er from lower dynamic range than CCDs due to their high read noise and nonuniformity. Moreover, as sensor design follows CMOS technology scaling, well capacity will continue to decrease, eventually resulting in unacceptably low SNR.
Study of the digital camera acquisition process and statistical modeling of
, 2013
"... the sensor raw data ..."
Analysis of Temporal Noise in CMOS Photodiode Active Pixel Sensor
 IEEE Journal of SolidState Circuits
, 2001
"... Temporal noise sets the fundamental limit on image sensor performance, especially under low illumination and in video applications. In a CCD image sensor, temporal noise is primarily due to the photodetector shot noise and the output amplifier thermal and 1 noise. CMOS image sensors suffer from hi ..."
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Temporal noise sets the fundamental limit on image sensor performance, especially under low illumination and in video applications. In a CCD image sensor, temporal noise is primarily due to the photodetector shot noise and the output amplifier thermal and 1 noise. CMOS image sensors suffer from higher noise than CCDs due to the additional pixel and column amplifier transistor thermal and 1 noise. Noise analysis is further complicated by the timevarying circuit models, the fact that the reset transistor operates in subthreshold during reset, and the nonlinearity of the charge to voltage conversion, which is becoming more pronounced as CMOS technology scales. The paper presents a detailed and rigorous analysis of temporal noise due to thermal and shot noise sources in CMOS active pixel sensor (APS) that takes into consideration these complicating factors. Performing timedomain analysis, instead of the more traditional frequencydomain analysis, we find that the reset noise power du...
Analysis of 1 Noise in Switched MOSFET Circuits
"... Analysw of 1/fnois in MOSFETcircuits is typically performed in the frequency domain usma these4((k) s4((k))4. 1/fnois model. Recent experimentalres)fifi however, have s4 wn that thees4(zwzfi us4( this model can be quite inaccuratees ecially forsr4 hed circuits In the cas of a periodicallyscal hedt ..."
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Analysw of 1/fnois in MOSFETcircuits is typically performed in the frequency domain usma these4((k) s4((k))4. 1/fnois model. Recent experimentalres)fifi however, have s4 wn that thees4(zwzfi us4( this model can be quite inaccuratees ecially forsr4 hed circuits In the cas of a periodicallyscal hedtransw4.z meass 1/fnois powers pectral densa y(ps] was s( wn to be s))][)4. tly lower than thees4fi[)k us4fi these4[( 1/f nois model. For a ring os4)w()(4. meas)w( 1/finducedphas nois ps was s wn to be s]wfi4. tly lower than thees4)fiw( us4) these4fifiww 1/fnois model. For aszwfifollowerres ( circuit, measit, 1/fnois power was als ss wn to be lower than thees4kfi] us4 these4((]fi 1/f model. In analyzingnois in the followerrescircuituscu frequency domain analyswk a low cuto# frequency thatis inversz proportional to the circuit ontimeis as4k[# The choice ofthis low cuto# frequencyis quite arbitrary and cancaus sausw[k t inaccuracy inesk[w]4. nois power. Moreover, duringresn the circuitis not ins4]([ s]([ and thus frequency domainanalys) does not apply. The paper prop osp a nons4.fikfi)4 extensfik of these4)fikk 1/fnois model, which allows us to analyze 1/f nois ins4(( hed MOSFETcircuits more accurately.Us) our model we analyzenois for the three aforementionedsone hed circuitexamples and obtain resin4 that arecons][) t with the reportedmeas(#)w] ts Researchparti[3 supported under the ProgrammableDiogra Camera Project byAgi'f t, Canon, HP, Interval Research, and Kodak. Key ords: 1/fnoisz phas noisz nonsz)4.#fi# nois model, time domainnois analys# CMOS imagesage4( periodicallyscal hedcircuits ringos4fiz][[4 1
Analysis of 1=f Noise in Switched
"... Abstract—Analysis of 1 noise in MOSFET circuits is typically performed in the frequency domain using the standard stationary 1 noise model. Recent experimental results, however, have shown that the estimates using this model can be quite inaccurate especially for switched circuits. In the case of a ..."
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Abstract—Analysis of 1 noise in MOSFET circuits is typically performed in the frequency domain using the standard stationary 1 noise model. Recent experimental results, however, have shown that the estimates using this model can be quite inaccurate especially for switched circuits. In the case of a periodically switched transistor, measured 1 noise power spectral density (psd) was shown to be significantly lower than the estimate using the standard 1 noise model. For a ring oscillator, measured 1induced phase noise psd was shown to be significantly lower than the estimate using the standard 1 noise model. For a source follower reset circuit, measured 1 noise power was also shown to be lower than the estimate using the standard 1 model. In analyzing noise in the follower reset circuit using frequencydomain analysis, a low cutoff frequency that is inversely proportional to the circuit ontime is assumed. The choice of this low cutoff frequency is quite arbitrary and can cause significant inaccuracy in estimating noise power. Moreover, during reset, the circuit is not in steady state, and thus frequencydomain analysis does not apply. This paper proposes a nonstationary extension of the standard 1 noise model, which allows us to analyze 1 noise in switched MOSFET circuits more accurately. Using our model, we analyze noise for the three aforementioned switched circuit examples and obtain results that are consistent with the reported measurements. Index Terms—1 noise, CMOS image sensor, nonstationary noise model, periodically switched circuits, phase noise, ring oscillator, timedomain noise analysis. I.