US 9,961,281 B2Granted

Image sensor pixel noise measurement

AssigneeOmniVision Technologies, Inc.

InventorsBi Yuan, Liping Deng, Yingkan Lin, Liang Zuo, Yuxin Wang

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Abstract

An image sensor pixel noise measurement circuit includes a pixel array on an integrated circuit chip. The pixel array includes a plurality of pixels including a first pixel to output a first image data signal, and a second pixel to output a second image data signal. A noise amplification circuit on the integrated circuit chip is coupled to receive the first and second image data signals from the pixel array. The noise amplification circuit is coupled to output an amplified differential noise signal in response to the first and second image data signals received from the pixel array. A fast Fourier transform (FFT) analysis circuit on the integrated circuit chip is coupled to transform the amplified differential noise signal output by the noise amplification circuit from a time domain to a frequency domain to analyze a pixel noise characteristic of the pixel array.

Claims15

Dependent claims

An image sensor pixel noise measurement circuit, comprising:

a pixel array on an integrated circuit chip, wherein the pixel array includes a plurality of pixels including a first pixel and a second pixel, the first pixel is coupled to output a first image data signal and the second pixel is coupled to output a second image data signal;
a noise amplification circuit on the integrated circuit chip coupled to receive the first and second image data signals from the pixel array, wherein the noise amplification circuit is coupled to output an amplified differential noise signal in response to the first and second image data signals received from the pixel array, wherein the noise amplification circuit is a multistage differential amplification circuit, wherein the multistage differential amplification circuit comprises a plurality of operational amplifiers cascaded in series to generate the amplified differential noise signal;
and
a fast Fourier transform (FFT) analysis circuit on the integrated circuit chip coupled to transform the amplified differential noise signal output by the noise amplification circuit from a time domain to a frequency domain to analyze a pixel noise characteristic of the pixel array.

1 more element

A method of measuring image sensor pixel noise, comprising:

generating first and second image data signals with first and second pixels of a pixel array on an integrated circuit chip;
generating an amplified differential noise signal in response to the first and second image data signals from the first and second pixels with a noise amplification circuit on the integrated circuit chip, wherein the noise amplification circuit is a multistage differential amplification circuit comprising a first, second, and third operational amplifiers cascaded in series to generate the amplified differential noise signal;
activating contemporaneously reset pixel phases in the first and second pixels and reset opamp phases in the first, second and third operational amplifiers;
sampling outputs of the first and second operational amplifiers while the reset pixel phases and reset opamp are activated;
deactivating the reset pixel phases in the first and second pixels to begin generating the first and second first and second image data signals;
deactivating separately and sequentially the reset opamp phases in the first, second, and third operational amplifiers;
and
transforming the amplified differential noise signal output by the noise amplification circuit from a time domain to a frequency domain with a fast Fourier transform (FFT) analysis circuit on the integrated circuit chip to analyze a pixel noise characteristic of the pixel array.

5 more elements

Dependencies are inferred from the claim text.