Robust and accurate freehand 3D ultrasound

A method for determining out of plane motion between a first ultrasound image and a second ultrasound image;

• comprising:
• dividing the first ultrasound image into a first plurality of patches, wherein each of the first plurality of patches has a first plurality of pixel data;
• dividing the second ultrasound image into a second plurality of patches, wherein each of the second plurality of patches has a second plurality of pixel data;
• combining one of the first plurality of pixel data with a corresponding one of the second pixel data;
• computing a signal to noise ratio value and a skewness value as statistical parameters corresponding to the combined pixel data;
• comparing the signal to noise ratio value and skewness value with a range of acceptable signal to noise ratio values and skewness values;
• depending on a result of the comparing, computing a correlation coefficient corresponding to the one of the first plurality of pixel data with the corresponding one of the second pixel data;
• computing an elevation distance corresponding to the correlation coefficient;
• and
• constructing a 3D image using the first ultrasound image, the second ultrasound image, and the elevation distance.

A system for generating 3D ultrasound images, comprising:

• an ultrasound probe;
• a processor coupled to the ultrasound probe;
• and
• a memory coupled to the processor,
• wherein the memory is encoded with instructions for acquiring a first ultrasound image and a second ultrasound image, the first ultrasound image corresponding to a first image location, and second ultrasound image corresponding to a second image location, and wherein the first image location and the second image location are separated by an elevation distance;
• dividing the first ultrasound image and the second ultrasound image into a plurality of patches;
• computing a signal to noise ratio value and a skewness value for each of the plurality of patches as statistical parameters that characterize a statistical distribution of speckle scattering within each of the plurality of patches;
• comparing the signal to noise ratio value and skewness value for each patch to a range of acceptable signal to noise ratio values and a range of acceptable skewness values;
• determining whether each patch of the plurality of patches is a good patch, wherein each good patch has a corresponding signal to noise ratio value and skewness value that lie within the range of acceptable signal to noise ratio values and skewness values;
• computing a correlation coefficient for a corresponding pair of good patches, wherein one of the corresponding pair is from the first ultrasound image, and the other of the corresponding pair is from the second ultrasound image;
• and
• computing an elevation distance corresponding to the correlation coefficient.

A system for generating 3D ultrasound images, comprising:

• an ultrasound probe;
• a processor coupled to the ultrasound probe;
• and
• a memory coupled to the processor, wherein the memory is encoded with instructions for acquiring a first ultrasound image and a second ultrasound image;
• dividing the first ultrasound image into a first plurality of patches, wherein each of the first plurality of patches has a first plurality of pixel data;
• dividing the second ultrasound image into a second plurality of patches, wherein each of the second plurality of patches has a second plurality of pixel data;
• combining one of the first plurality of pixel data with a corresponding one of the second pixel data;
• computing a signal to noise ratio value and a skewness value corresponding to the combined pixel data;
• comparing the signal to noise ratio value and skewness value with a range of acceptable signal to noise ratio values and skewness values;
• depending on a result of the comparing, computing a correlation coefficient corresponding to the one of one of the first plurality of pixel data with the corresponding one of the second pixel data;
• computing an elevation distance corresponding to the correlation coefficient;
• and constructing a 3D image using the first ultrasound image, the second ultrasound image, and the elevation distance.