What is speckle microscopy?

Fluorescent speckle microscopy (FSM) is a live imaging and quantitative measurement technique used for analyzing motion and turnover of macromolecular assemblies in vivo and in vitro. These puncta, called speckles, serve as fiduciary markers so that motion and turnover of the structure are visualized.

How is speckle formed?

Speckle patterns typically occur in diffuse reflections of monochromatic light such as laser light. Such reflections may occur on materials such as paper, white paint, rough surfaces, or in media with a large number of scattering particles in space, such as airborne dust or in cloudy liquids.

Why is laser light speckled?

Speckle occurs because the laser light is temporally coherent and is scattered from a random surface. The random surface causes a large number of wavelets to leave the object and overlap in space, each wavelet having a random phase relationship to all the others.

What are laser speckles?

Laser speckle is the random interference pattern produced when coherent light scatters from a random medium and can be imaged onto a detector. Motion from scattering particles, such as red blood cells in the vasculature, leads to spatial and temporal variations in the speckle pattern.

How many types of speckle patterns are there?

The two basic types of speckle patterns are explained below: Subjective speckle pattern – Speckle patterns produced at an image plane of a lens are called subjective speckle pattern. Subjective patterns are caused by the interference of waves from the various scattering regions of a resolution element of the lens.

How do you remove a laser speckle?

The speckle generated by the diffuser is used to vary the phase of the illumination of the rough object. One method to reduce speckle involves scanning a beam on a diffuser rather than scanning the diffuser on the beam.

How do you stop a laser speckle?

Speckle can often be avoided, e.g. by using a light source with sufficiently large optical bandwidth (short coherence length) such as a superluminescent source. (How much bandwidth is required for that purpose depends on the situation.) For projection displays, one may also work with an optimized screen.

What causes speckle in a radar image?

Speckle appears as a grainy “salt and pepper” texture in an image. This is caused by random constructive and destructive interference from the multiple scattering returns that will occur within each resolution cell.

What is speckle correlation?

The speckle field scattered from the surface is used as information carrier and its change is measured by correlation. This is realized by sophisticated data acquisition and digital processing techniques. For a verification, speckle decorrelation in model surfaces of known deviation is measured.

How do you make a speckle pattern?

The usual method of generating a speckle pattern is by manually spraying the paint on the specimen. However, this makes it difficult to reproduce the optimal pattern for maintaining identical testing conditions and achieving consistent DIC results.

What are the parts of a diopter microscope?

Diopter Adjustment: Useful as a means to change focus on one eyepiece so as to correct for any difference in vision between your two eyes. Body tube (Head): The body tube connects the eyepiece to the objective lenses. Arm: The arm connects the body tube to the base of the microscope. Coarse adjustment: Brings the specimen into general focus.

What are the structural parts of a microscope?

There are three structural parts of the microscope i.e. head, base, and arm. Head – This is also known as the body, it carries the optical parts in the upper part of the microscope. Base – It acts as microscopes support. It also carries microscopic illuminators.

Where is the eyepiece on a microscope?

Eyepiece – also known as the ocular. this is the part used to look through the microscope. Its found at the top of the microscope. Its standard magnification is 10x with an optional eyepiece having magnifications from 5X – 30X.

What type of lens is used in a microscope?

Most microscopes use achromatic lens with more exacting applications requiring plan or semi-plan objectives. Arm: The part of the microscope that connects the eyepiece tube to the base.