# Sensing matrix for compressed sensing

• What are the differences between random binary sensing matrix  and random Gaussian sensing matrix?

How can I choose the suitable matrix for a certain signal?

A sensing matrix maps input vector to measurement vector through linear wighted summation of input. What makes a specific matrix good, is application dependent. Now, both distributions more or less satisfy RIP. However hardware implementation of the Bernoulli matrix (binary or bipolar) is much much easier especially in analog domain. A Bernoulli wight is either 0 or 1 (or -1/1 in case of polar Bernoulli), but a Gaussian wight is a floating point figure. Multiplication of a flouting point number either in digital or analog, is resource consuming, while multiplication of a Bernoulli wight is feasible through implementation of a simple switch in analog domain or an and instruction in digital. As an example consider RMPI analog to information devices which compressively sample the signal in analog and then reconstruct the signal in digital. Prior to quantization the sensing matrix should be applied, were through incorporating a Bernoulli matrix, the multipliers are implemented as simples switches. I also think, Gaussian Matrix has tighter RIP than Bernoulli (especially binary Bernoulli). As an example assume we have an sparse matrix $X=[0,1,0,2,0]^T$ , and assume we are measuring it using a random matrix with two rows and 5 columns. A binary Bernoulli, is more probable to multiply one of the non sparse entries by zero and hence miss its contribution in the measurements vector. Also, having only 1,0 and -1, the matrix rows are more probable to be similar and hence more coherency occurs.

Although it seems unwise, in this paper the authors presented an analog circuit for application of Gaussian Matrix.

• Thanks for your answer. This means that the energy consumption is less using the binary matrix, right? @MimSaad – Mohamed Aly Apr 13 '17 at 8:02
• Yes, thats right. – MimSaad Apr 13 '17 at 13:12
• OK, Would you provide the reference?I'll take a look. Adding this might help others who have this question. – MimSaad Apr 13 '17 at 16:25
• I don not have a reference. This observation is through trials. @MimSaad – Mohamed Aly Apr 14 '17 at 11:11
• I guess it was because Gaussian matrix more incoherent that Bernoulli. However, I suggest to post another question, and explain your observation and details of your numerical experimentations. – MimSaad Apr 14 '17 at 12:16