TRANSMISSION ANGLE CALIBRATION

1 . A method comprising:

receiving data characterizing a plurality of acoustic signals reflected by a defect in a target object, and a first depth of the defect relative to a surface of the target object,

wherein a first acoustic signal and a second acoustic signal are detected by a detector at a first location and a second location, respectively, on the surface of the target object, the plurality of acoustic signal includes the first acoustic signal and the second acoustic signal;

determining an envelope function based on at least the first acoustic signal and the second acoustic signal;

identifying a target distance between the detector and the defect, wherein the target distance is associated with a peak value of the envelop function; and

calculating a detection angle based on the target distance and the first depth of the defect.

2 . The method of claim 1 , further comprising:

rendering, in a graph in a graphical user interface display space, a first visual representation of the first acoustic signal and a second visual representation of the second acoustic signal, the graph including a first axis indicative of distance between the defect and the detector, and a second axis indicative of amplitudes of acoustic signals detected by the detector; and

rendering, in the graph, a third visual representation of the envelop function.

3 . The method of claim 2 , further comprising rendering, in the graph, a fourth visual representation of a measurement gate, wherein the fourth visual representation is rendered between a first distance value and a second distance value on the first axis and between a first acoustic amplitude value and a second acoustic amplitude value on the second axis.

4 . The method of claim 3 , further comprising receiving a first user input indicative of the first distance value and a second user input indicative of the second distance value.

5 . The method of claim 3 , further comprising receiving a third user input indicative of the first acoustic amplitude value and a fourth user input indicative of the second acoustic amplitude value.

6 . The method of claim 3 , further comprising determining the first distance value and the second distance value by a predetermined function, wherein the predetermined function is configured to receive the target distance as input and provide the first distance value and the second distance value as output.

7 . The method of claim 3 , further comprising displaying peak values associated with one or more acoustic signals of the plurality of acoustic signals that have peak values detected between the first location value and the second location value, and wherein the peak values are greater than the third acoustic amplitude value and the fourth acoustic amplitude value.

8 . The method of claim 1 , wherein the envelop function is determined by fitting peak values of the at least the first acoustic signal and the second acoustic signal.

9 . The method of claim 1 , further comprising identifying a location range associated with the first axis, wherein the location range includes locations of the detector at which measurement of each of the plurality of acoustic signal is performed.

10 . A system comprising:

at least one data processor;

memory coupled to the at least one data processor, the memory storing instructions to cause the at least one data processor to perform operations comprising:

receiving data characterizing a plurality of acoustic signals reflected by a defect in a target object, and a first depth of the defect relative to a surface of the target object, wherein a first acoustic signal and a second acoustic signal are detected by a detector at a first location and a second location, respectively, on the surface of the target object, the plurality of acoustic signal includes the first acoustic signal and the second acoustic signal;

determining an envelope function based on at least the first acoustic signal and the second acoustic signal;

identifying a target distance between the detector and the defect, wherein the target distance is associated with a peak value of the envelop function; and

calculating a detection angle based on the target distance and the first depth of the defect.

11 . A computer program product comprising a machine-readable medium storing instructions that, when executed by at least one programmable processor, cause the at least one programmable processor to perform operations comprising:

receiving data characterizing a plurality of acoustic signals reflected by a defect in a target object, and a first depth of the defect relative to a surface of the target object,

wherein a first acoustic signal and a second acoustic signal are detected by a detector at a first location and a second location, respectively, on the surface of the target object, the plurality of acoustic signal includes the first acoustic signal and the second acoustic signal;

determining an envelope function based on at least the first acoustic signal and the second acoustic signal;

identifying a target distance between the detector and the defect, wherein the target distance is associated with a peak value of the envelop function; and

calculating a detection angle based on the target distance and the first depth of the defect.