Method of detecting an amplitude transient in a field of elements having a multivalent amplitude distribution, device suitable for performing the method, and video system including the device

Claim 3

A method as claimed in claim 1, wherein said line is directed in a first direction, said field and each said array of signal elements are arranged in at least two dimensions, so as to define three groups of signal elements arranged in three respective parallel further lines directed in a second direction, each group containing a different one of said three signal elements, and said determining the location of the amplitude transient along said line directed in said first direction comprises forming three respective sums of the amplitude values of the three groups of signal elements, and said interpolating is as a function of each of said three respective sums.

Claim 4

A method as claimed in claim 2, wherein the location of the amplitude transient is determined by means of a fitted curve defining said function of said three respective sums.

Claim 5

A method as claimed in claim 1, wherein the signal elements of said field comprise pixels of a two-dimensional video image, grey-levels of the pixels constituting the amplitude values.

Claim 6

A method as claimed in claim 1, wherein the field of signal elements has one or more principal directions and the search curve is chosen to extend in one of the principal directions.

Claim 7

A method as claimed in claim 1, wherein the location of the amplitude transient is determined by means of a fitted curve defining said function of the amplitude values of said three signal elements.

Claim 10

A device as claimed in claim 7, wherein the detection and location circuit means comprises an adder circuit, and read-only memory means containing a table of logarithms and a table of anti-logarithms.

Claim 11

A video display system for repeatedly detecting and localizing an amplitude transient in real-time through a succession of fields, corresponding to video images, of regularly spaced apart signal elements with a multivalent amplitude distribution by searching along a search curve directed through each field, said system comprising: means for obtaining amplitude values of successive arrays of said signal elements selected by respective successive positions of a window onto each said field advanced along said search curve, each array including three signal elements arranged along a line, said obtaining means including storage elements for storing the amplitude values of a current array of signal elements; and detection and location circuit means responsive to said storage elements configured for detecting the occurrence of an amplitude transient along said line and determining the location along said line of the detected amplitude transient by interpolating to a fraction, less than 1/2, of the spacing between adjoining signal elements along said line as a function of the amplitude values of each of said three signal elements.

Claim 12

A video display system for repeatedly detecting and localizing an amplitude transient in real-time through a succession of fields, corresponding to video images, of regularly spaced apart signal elements with a multivalent amplitude distribution by searching along a search curve directed through each field, said system comprising: means for obtaining amplitude values of successive arrays of said signal elements selected by respective successive positions of a window onto each said field advanced along said search curve, each array including three signal elements arranged along a line, said obtaining means including storage elements for storing the amplitude values of a current array of signal elements; and detection and location circuit means responsive to said storage elements configured for detecting the occurrence of an amplitude transient along said line and determining the location along said line of the detected amplitude transient by interpolating to a fraction, less than 1/2, of the spacing between adjoining signal elements along said line as a function of the amplitude values of each of said three signal elements.

Claim 15

A method as claimed in claim 10, wherein said fitted curve corresponds to a third-order polynomial, an inflexion point of said polynomial being the location determined.

Claim 16

A method as claimed in claim 10, wherein said line is directed in a first direction, said field and each said array of signal elements are arranged in at least two dimensions, so as to define four groups of signal elements arranged in four respective parallel further lines directed in a second direction, each group containing a different one of said four signal elements, and said determining the location of the amplitude transient along said line directed in said first direction comprises forming four respective sums of the amplitude values of the four groups of signal elements, and said interpolating is as a function of each of said four respective sums.

Claim 17

A method as claimed in claim 12, wherein the location of the amplitude transient is determined by means of a fitted curve defining said function of said four respective sums.

Claim 18

A method as claimed in claim 13, wherein said fitted curve corresponds to a third-order polynomial, an inflexion point of said polynomial being the location determined.