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This module provides an overview of architectures and methods for hyperspectral imaging using the ideas of compressive sensing.

Standard digital color images of a scene of interest consist of three components – red, green and blue – which contain the intensity level for each of the pixels in three different groups of wavelengths. This concept has been extended in the hyperspectral and multispectral imaging sensing modalities, where the data to be acquired consists of a three-dimensional datacube that has two spatial dimensions x and y and one spectral dimension λ .

In simple terms, a datacube is a 3-D function f ( x , y , λ ) that can be represented as a stacking of intensities of the scene at different wavelengths. An example datacube is shown in [link] . Each of its entries is called a voxel. We also define a pixel's spectral signature as the stacking of its voxels in the spectral dimension f ( x , y ) = { f ( x , y , λ ) } λ . The spectral signature of a pixel can give a wealth of information about the corresponding point in the scene that is not captured by its color. For example, using spectral signatures, it is possible to identify the type of material observed (for example, vegetation vs. ground vs. water), or its chemical composition.

Datacubes are high-dimensional, since the standard number of pixels present in a digitized image is multiplied by the number of spectral bands desired. However, considerable structure is present in the observed data. The spatial structure common in natural images is also observed in hyperspectral imaging, while each pixel's spectral signature is usually smooth.

Example hyperspectral datacube, with labeled dimensions.

Compressive sensing (CS) architectures for hyperspectral imaging perform lower-dimensional projections that multiplex in the spatial domain, the spectral domain, or both. Below, we detail three example architectures, as well as three possible models to sparsify hyperspectral datacubes.

Compressive hyperspectral imaging architectures

Single pixel hyperspectral camera

The single pixel camera uses a single photodetector to record random projections of the light emanated from the image, with the different random projections being captured in sequence. A single pixel hyperspectral camera requires a light modulating element that is reflective across the wavelengths of interest, as well as a sensor that can record the desired spectral bands separately  [link] . A block diagram is shown in [link] .

The single sensor consists of a single spectrometer that spans the necessary wavelength range, which replaces the photodiode. The spectrometer records the intensity of the light reflected by the modulator in each wavelength. The same digital micromirror device (DMD) provides reflectivity for wavelengths from near infrared to near ultraviolet. Thus, by converting the datacube into a vector sorted by spectral band, the matrix that operates on the data to obtain the CS measurements is represented as

Φ = Φ x , y 0 0 0 Φ x , y 0 0 0 Φ x , y .

This architecture performs multiplexing only in the spatial domain, i.e. dimensions x and y , since there is no mixing of the different spectral bands along the dimension λ .

Questions & Answers

how did psychology begin?
Valerie Reply
of psychologys commencement, the traces can be seen in the work of Aristotle, where he talk about soul and body, likewise work in durrant, de anima, all these were somewhere supporting dualism, in which soul could exist separately from body
but if you talk about the moder psychology, Gustav fechner, is credited with performing scientific experiments, basis of his experiments in psychology with his studies perception.
does psychology deal with love?
Mohammed Reply
Maybe, i think
I definitely would say yes
how so
there are so many different reasons why you can fall in love with someone, many of them develope subconsciously -> psychology
love messes with the brain, a lot, ergo I believe that Psychology does indeed deal with love
what is synapse
Katie Reply
In the central nervous system, a synapse is a small gap at the end of a neuron that allows a signal to pass from one neuron to the next. synapse are found where nerve cells connect with other nerve cells
can you do auto book auto
Mariah Reply
WHT u mean?
heyy, may i join the conversation please?
edem Reply
who is the father of psychology
Richy Reply
and please, how would you guys, describe the study of psychology at college ?
psychologist student?
i mean not yet but am about to start college so wanna know how is it(college in general and psychology course) please
Psychology is the study of mind and behaviour. So if you will take psychology as a subject so you will get to know how your everything (physical, mental, social, spiritual aspects) effects your behaviour
With this brief knowledge you can help people to cope up with their problems and only you can guide them correctly
And if you go for further specialisations you can study hypnosis, face reading, body language etc
Thanks a lot🙏🏾 And ik some of the stuffs u said but i am also going to write thesis, right ?
ok no prob, thanks a lot🙏🏾✨
hae everyone, hope you are well this evning my question is what is the difference between drive and motivation
good question
drive is more like an impulse or urge and i think they both go together (drive and motivation) even if there is a slight difference
@ Michael Drive is delivered to be innate without the use of an external stimuli, motivation normally evolves an outside stimuli which may include praise, appreciate, or reward.
*believed...sorry for typo
@Reginald, can't the motivation come from the inner self?
Good question, please give an example.
can we say desire of success for example
Wilhelm Wundt is the father of psychology
Wilhem Wundt thank you for the road that you opened.
You mean who is the father of having a great educated argumentative guess? nothing is more wrong than this question. The question is you should ask yourselfs is, how sure are you abour their scientific studying? one's percieved assimilated approach to judging another person and saying they are
the biggest problem with scientific research and data is that ya you could get the same result 1000 times then it could go the other way 1000 times, but we would never know that and we did, we would still say ya but the proof is there. The only thing science proves is that humanity has
no facts about human behavior in the scientific context, but more in the trial and error.. sorry to tell you, but so far no one has proven Father of anything, thats up to you and i, judgement is bias, science is good enough lazy
cognitive development is the growing and development of the brain.
Jessy Reply
Anyone knows about Techno-fascism?
Hussein Reply
Ecofascism is a theoretical political model in which an authoritarian government would require individuals to sacrifice their own interests to the "organic whole of nature". The term is also used as a rhetorical pejorative to undermine the environmental movement.
what's the big difference between prejudice and discrimination?
Danice Reply
A prejudiced person may not act on their attitude.  Therefore, someone can be prejudiced towards a certain group but not discriminate against them.  Also, prejudice includes all three components of an attitude (affective, behavioral and cognitive), whereas discrimination just involves behavior
Nancy Lee
what is all about cognitive development?
cognitive development is the growing and development of the brain
how do you control a variable when using spss whilst running a pearsons correlation analysis?
Jessie Reply
it dependa on your study. according to what you want to say and explain your result
why does it say her and she
Jayla Reply
stages of cognitive development
brivia Reply
sensory preoperatinal concrete formal
what is psychology
Chethani Reply
the study of insecurities and the effect on the host .
Psychology is the scientific study of behavior & mental processes
psychology is science about learning human behaviour
In thinking about the case of Candace described earlier, do you think that Candace benefitted or suffered as a result of consistently being passed on to the next grade?
Nene Reply
what is reward
Angeles Reply
reward is a technique to change behaviour
Reward is a way to promote a specific behaviour or to teach someone/ something to behave a specific way or perform a specific task.
a reward is something that is usually associated with desirable behavior. The child got a reward for winning the game. A reinforcer is different in that a reinforcer is anything that increases behavior, even if it is increasing an undesirable behavior.
reward is earned effort realized
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Source:  OpenStax, An introduction to compressive sensing. OpenStax CNX. Apr 02, 2011 Download for free at http://legacy.cnx.org/content/col11133/1.5
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