What is Synthetic Aperture Imaging?

Synthetic aperture radar (SAR) imaging, is a technique that allows us to remotely map the reflectivity of objects or environments with high spatial resolution, through the emission and reception of electromagnetic (EM) signals.

What is SA ultrasound?

Abstract. The paper describes the use of synthetic aperture (SA) imaging in medical ultrasound. SA imaging is a radical break with today’s commercial systems, where the image is acquired sequentially one image line at a time.

What does aperture mean in ultrasound?

Aperture size and wavelength: The aperture is the active area that transmits or receives acoustic wave at certain moment. For a single-element transducer, the aperture size is the transducer element size. For array transducer, the aperture are all the elements that works together simultaneously.

What is ultrasound beamforming?

Beamforming is used to activate the transducer array elements in a controlled manner during transmission of ultrasound beams and reception of the reflected echoes to form a high-quality ultrasound image of the desired field of interest.

What can SAR be used for?

Synthetic-aperture radar (SAR) is a form of radar that is used to create two-dimensional images or three-dimensional reconstructions of objects, such as landscapes. SAR uses the motion of the radar antenna over a target region to provide finer spatial resolution than conventional stationary beam-scanning radars.

What is active aperture?

The Active Aperture is the total probe active length. A => Active aperture. g => Gap between two adjacent elements. e=> Width of a single piezocomposite element, its typical value is ≤ λ/2.

What does dynamic aperture improve?

Dynamic aperture control technology is one of the most important parts in ultrasonic imaging system. Excellent control technology of dynamic aperture can effectively improve the quality of ultrasonic imaging.

What is the virtual beamforming ultrasound?

Ultrasound beamforming relies on models of propagation to convert samples of the backscattered field through time into spatial image samples. The most common model is straight-line propagation of a focused wave, assuming a narrow steered and focused beam that propagates along a selected direction.

What effect does virtual beam forming and parallel processing have on detail and temporal resolution?

Virtual beam-forming provides improved detail resolution (i.e., the entire image is in focus; see Figure 2), contrast resolution and temporal resolution (fewer pulses are required to acquire all the echo information for an image; frame rates can be in the 100’s), increased sensitivity and penetration, artifact …

What is the benefit of synthetic aperture radar?

The Benefits of Synthetic Aperture Radar (SAR) Capella’s constellation of synthetic aperture radar (SAR) satellites provides 24-hour all-weather Earth observation. What makes SAR unique is its ability to penetrate atmospheric conditions, providing near real-time visibility in cloud covered areas, both day and night.

How does synthetic aperture work?

A synthetic aperture radar (SAR) is an active sensor that first transmits microwave signals and then receives back the signals that are returned, or backscattered , from the Earth’s surface. The instrument measures distances between the sensor and the point on the Earth’s surface where the signal is backscattered.

What are the disadvantages of SAR?

The main disadvantage of pulse-based UWB SAR is that the transmitting and receiving front-end electronics are difficult to design for high-power applications.

Is CT scan more accurate than ultrasound?

To diagnose painful kidney stones in hospital emergency rooms, CT scans are no better than less-often-used ultrasound exams, according to a clinical study conducted at 15 medical centers.

What is focal law?

Focal Law: Strictly, a mathematical formula used for firing the phased array instrument. More generally, a file containing the entire set of hardware and software parameters for phased array operation, which defines the elements to be fired, time delays, voltages, for both the transmitter and receiver functions.

Why is a dynamic aperture used?

A technique called dynamic aperture can be used to make a sound beam narrow over a greater range of depths and thus optimize lateral resolution. When an array transducer is used, the US system may change the number of crystals along the face of the probe used to transmit pulses and receive reflections.

What is synthetic aperture imaging in medical ultrasound?

The paper describes the use of synthetic aperture (SA) imaging in medical ultrasound. SA imaging is a radical break with today’s commercial systems, where the image is acquired sequentially one image line at a time.

What is the history of synthetic aperture?

… Synthetic aperture (SA) finds its origin from the radar application in 1950s and has been investigated in ultrasounds since the late 1960. If during a period the use of the method for ultrasound application was punctual, the technique finds an interest for Doppler and high frame rate imaging (Jensen et al., 2006) (Trots et al., 2011).

When was synthetic aperture sonar first used in medicine?

In 1972, Burckhardt first put forward the idea that uses synthetic aperture sonar in medical applications and proved that a synthetic aperture system gives a significantly higher lateral resolution than a conventional B-scan. In 1980, Corl proposed a real-time system implementation for synthetic aperture in medical use.

How can medical SA ultrasound imaging be acquired and processed?

This paper has given examples of how medical SA ultrasound imaging can be acquired and processed. It has been shown that problems with penetration depth, flow, and motion can be solved, and that high quality in vivo SA images can be acquired.