Ultrasound is an inexpensive and widely used imaging modality for the diagnosis and staging of a number of diseases. In the past two decades, it has benefited from major advances in technology and has become an indispensable imaging modality, due to its flexibility and non-invasive character. Ultrasound imaging utilizes high-frequency sound waves to picture inner structures by contrasting reflection signals created when a light emission is anticipated into the body and ricochets back at interfaces between the structures. However the convenience of ultrasound imaging is corrupted by the nearness of flag dependant noise known as dot (speckle). The speckle pattern depends on the structure of the image tissue and various imaging parameters. Speckle noise show in ultrasound picture influences edges and fine subtle elements which constrain the differentiation determination and make symptomatic more troublesome. There are two main purposes for speckle reduction in medical ultrasound imaging (i) To improve the human interpretation of ultrasound images (ii) De-speckling is the preprocessing step for many ultrasound image processing tasks such as segmentation and registration. Various strategies have been proposed for decrease speckle noise in ultrasound imaging. The objective of this paper is to give an overview of speckle noise reduction in ultrasound imaging.
Keywords: Speckle noise, Ultrasound image, Different methods, filters analysis
I. INTRODUCTIONUltrasound imaging assumes pivotal part in therapeutic imaging because of its non-obtrusive nature, ease and capacity of framing ongoing imaging. Medical Ultrasound imaging is done using ultrasonic waves in 3 to 20 MHz range. Ultrasound waves are created from the transducer and go through body tissues and when the wave achieves a protest or surface with various surface or acoustic in nature, it is reflected back. These echoes are received by the apparatus (the transducer array) and converted into electric current. These signals are amplified, conditioned and shown on a display device in real time. The image generated using Ultrasound imaging commonly known as Ultrasound Scanning is called an Ultra sonogram. The resolution of the image will be better by using higher frequencies but at the same time limits the depth of the penetration. There are diverse methods of ultrasound imaging.The most common modes are (a) B-mode -the basic two-dimensional intensity mode, (b) M-mode to assess moving body parts (e.g. cardiac movements) from the echoed sound and (c) Color mode pseudo coloring based on the detected cell motion. Ultrasound imaging is a generally utilized and safe restorative indicative system, because of its non intrusive nature, minimal effort and capacity of framing ongoing imaging. To accomplish the most ideal determination it is vital that medicinal pictures be sharp, clear and free of commotion and ancient rarities. However event of spot noise is an issue with ultrasound imaging. Spot is the curio caused by impedance of vitality from haphazardly appropriate...