Patent ID: 8619494

Claim:
Imaging apparatus for imaging the spatial distribution of the acoustic properties of a sample, the apparatus comprising: at least one ultrasonic transmitter operable to generate an ultrasonic beam across an imaging area; at least one ultrasonic receiver sensitive to intensity of an ultrasonic field generated by the transmitter or transmitters, the at least one ultrasonic receiver comprising: an ultrasonic absorber; and a film which is divided into a plurality of separate elements comprising: at least one pyroelectric ultrasonic sensing element in thermal communication with the ultrasonic absorber, which is sensitive to heating caused by the ultrasonic field and which has an accelerometer response; and at least one pyroelectric compensation element which is substantially insensitive to heating caused by the ultrasonic field and which has an accelerometer response substantially similar to that of the at least one pyroelectric ultrasonic sensing element; wherein the at least one ultrasonic receiver is arranged to sense the ultrasonic field in a part of the imaging area; and signal processing circuitry operable to process a signal from the at least one ultrasonic receiver to derive therefrom an intensity measure across said imaging area, and thus to derive a spatial distribution of the acoustic properties of a sample in the field across said imaging area, wherein the signal processing circuitry is further operable to remove the signal from the at least one pyroelectric compensation element from the signal from the at least one pyroelectric ultrasonic sensing element so as to compensate for the accelerometer response of the at least one pyroelectric ultrasonic sensing element.