Noise characteristics of heterodyne/homodyne frequency-domain measurements

Kang, Doosun; Kupinski, Matthew A.

doi:10.1117/1.jbo.17.1.015002

Cited by 6 publications

(6 citation statements)

References 37 publications

(73 reference statements)

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“…Although recently developed noise models for heterodyne and homodyne measurements indicate that small m p reduces σ 2 AC in Eq. (4), 27 the decreased σ 2 AC does not improve the estimation forφ because γ in Eq. (14) depends on only a AC and σ 2 DC .…”

Section: Further Discussion and Conclusionmentioning

confidence: 99%

“…Recently, the covariance of a heterodyne and/or homodyne output was theoretically derived from the random amplification of a temporal point process. 27 The model of covariance implies that the variance of heterodyne outputs can be expressed as the form of σ 2 p ðtÞ in Eq. (4) and both σ 2 DC and σ 2 AC are affected by a Fano factor F 24 of image intensifiers, which is experimentally verified.…”

Section: Theory Developmentmentioning

confidence: 99%

“…(19) is equivalent to the Noise Factor NF, when primary photons are assumed as Poisson. 27 Therefore, NF, commonly used in noise analyses for photon amplifiers, affects γ profoundly. It is known that NF can be minimized with a very high image intensifier gain, which is 3.5 to 4.2 and 1.6 to 2.2 for second-and third-generation image intensifiers, respectively.…”

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confidence: 99%

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Effect of noise on modulation amplitude and phase in frequency-domain diffusive imaging

Kang

Kupinski

2012

J. Biomed. Opt

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Abstract. We theoretically investigate the effect of noise on frequency-domain heterodyne and/or homodyne measurements of intensity-modulated beams propagating through diffusive media, such as a photon density wave. We assumed that the attenuated amplitude and delayed phase are estimated by taking the Fourier transform of the noisy, modulated output data. We show that the estimated amplitude and phase are biased when the number of output photons is small. We also show that the use of image intensifiers for photon amplification in heterodyne or homodyne measurements increases the amount of biases. Especially, it turns out that the biased estimation is independent of AC-dependent noise in sinusoidal heterodyne or homodyne outputs. Finally, the developed theory indicates that the previously known variance model of modulation amplitude and phase is not valid in low light situations. Monte-Carlo simulations with varied numbers of input photons verify our theoretical trends of the bias.

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Section: Further Discussion and Conclusionmentioning

confidence: 99%

Section: Theory Developmentmentioning

confidence: 99%

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Effect of noise on modulation amplitude and phase in frequency-domain diffusive imaging

Kang

Kupinski

2012

J. Biomed. Opt

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“…Projected photons from the double conical mirrors pass through filters (a combination of 515 long pass filter and 515/30 or 595/20 or 625/20 nm band pass filter, Chroma Technology Corp., USA) and a lens (AF Nikkor 50 mm f/1.8D, Nikon, Japan) in front of the intensifier. To determine amplitude modulations and phase shifts for the frequency domain measurements, we implemented a homodyne imaging method [15][16][17]. The gain of the intensifier is modulated at the same frequency as the source.…”

Section: Detection Unitmentioning

confidence: 99%

Non-contact small animal fluorescence imaging system for simultaneous multi-directional angular-dependent data acquisition

Lee¹,

Kim²,

Chandhanayingyong³

et al. 2014

Biomed. Opt. Express

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Abstract:We present a novel non-contact small animal fluorescent molecular tomography (FMT) imaging system. At the heart of the system is a new mirror-based imaging head that was designed to provide 360-degree measurement data from an entire animal surface in one step. This imaging head consists of two conical mirrors, which considerably reduce multiple back reflections between the animal and mirror surfaces. These back reflections are common in existing mirror-based imaging heads and tend to degrade the quality of raw measurement data. In addition, the introduction of a novel ray-transfer operator allows for the inclusion of the angular dependent data in the image reconstruction process, which results in higher image resolution. We describe in detail the system design and implementation of the hardware components as well as the transport-theorybased image reconstruction algorithm. Using numerical simulations, measurements on a well-defined phantom and a live animal, we evaluate the system performance and show the advantages of our approach.

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“…[26][27][28][29][30][31][32][33] Usually, the gain of the PMT is modulated at a frequency that is near (the same as) the modulation frequency of the excitation light source to generate a low beat frequency (dc) signal at the output of the PMT. Because the heterodyne (homodyne) detection technique reduces the frequency bandwidth of the system, the large value of the load resistor can be connected to the output of the PMT.…”

Section: Introductionmentioning

confidence: 99%

Photon-counting 1.0 GHz-phase-modulation fluorometer

Mizuno

Nakao

Mizutani

et al. 2015

Review of Scientific Instruments

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We have constructed an improved version of a photon-counting phase-modulation fluorometer (PC-PMF) with a maximum modulation frequency of 1.0 GHz, where a phase domain measurement is conducted with a time-correlated single-photon-counting electronics. While the basic concept of the PC-PMF has been reported previously by one of the authors, little attention has been paid to its significance, other than its weak fluorescence measurement capability. Recently, we have recognized the importance of the PC-PMF and its potential for fluorescence lifetime measurements. One important aspect of the PC-PMF is that it enables us to perform high-speed measurements that exceed the frequency bandwidths of the photomultiplier tubes that are commonly used as fluorescence detectors. We describe the advantages of the PC-PMF and demonstrate its usefulness based on fundamental performance tests. In our new version of the PC-PMF, we have used a laser diode (LD) as an excitation light source rather than the light-emitting diode that was used in the primary version. We have also designed a simple and stable LD driver to modulate the device. Additionally, we have obtained a sinusoidal histogram waveform that has multiple cycles within a time span to be measured, which is indispensable for precise phase measurements. With focus on the fluorescence intensity and the resolution time, we have compared the performance of the PC-PMF with that of a conventional PMF using the analogue light detection method.

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Noise characteristics of heterodyne/homodyne frequency-domain measurements

Cited by 6 publications

References 37 publications

Effect of noise on modulation amplitude and phase in frequency-domain diffusive imaging

Effect of noise on modulation amplitude and phase in frequency-domain diffusive imaging

Non-contact small animal fluorescence imaging system for simultaneous multi-directional angular-dependent data acquisition

Photon-counting 1.0 GHz-phase-modulation fluorometer

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