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Noise in laser imaging. Penumbrol imaging is a technique
Chapter 4, Problem 80E(choose chapter or problem)
Noise in laser imaging. Penumbrol imaging is a technique used by scanning companies for imaging objects (e.g., X-rays and lasers) that emit high-energy photons. In IEICE Transactions on Information & Systems (Apr. 2005), researchers demonstrated that penumbrol images are always degraded by noise, where the number x of noise events occurring in a unit of time follows a Poisson process with mean \(\lambda\). Suppose that \(\lambda =9\) for a particular image.
a. Find and interpret the mean of x.
b. Find the standard deviation of x.
c. The signal-to-noise ratio (SNR) for a penumbrol image is defined as \(SNR=\mu/\sigma\), where \(\mu\) and \(\sigma\) are the mean and standard deviation, respectively, of the noise process. Find the SNR for x.
Questions & Answers
QUESTION:
Noise in laser imaging. Penumbrol imaging is a technique used by scanning companies for imaging objects (e.g., X-rays and lasers) that emit high-energy photons. In IEICE Transactions on Information & Systems (Apr. 2005), researchers demonstrated that penumbrol images are always degraded by noise, where the number x of noise events occurring in a unit of time follows a Poisson process with mean \(\lambda\). Suppose that \(\lambda =9\) for a particular image.
a. Find and interpret the mean of x.
b. Find the standard deviation of x.
c. The signal-to-noise ratio (SNR) for a penumbrol image is defined as \(SNR=\mu/\sigma\), where \(\mu\) and \(\sigma\) are the mean and standard deviation, respectively, of the noise process. Find the SNR for x.
ANSWER:Answer
Step 1 of 3
(a)
Researchers demonstrated that penumbral images are always degraded by noise.
The number of noise events occurring in a unit of time follows a Poisson process with mean
Suppose that for a particular image.
We are asked to find and interpret the mean of
A random variable is said to have a Poisson probability distribution if and only if
…………(1)
A random variable possessing a Poisson probability distribution with parameter then
Since we have given for a particular image.
Hence we can write the mean of
Hence the mean of is in unit of time.
And the meaning of this is that the average of 9 noise events in a unit of time.