generateSectorMatri​x

This code generates a matrix that constructs a theta angle sector showcasing a specified orientation and corresponding amplitude.

Input Parameters:

• siz: Size of the generated matrix. % % a array, for example [100, 100];
• x0 and y0: Coordinates of the transducer location, which also stands for the center of the sector. % % two integers, for example 20 and 168;
• r: Emitting radius, the radius of the sector. % % one integer, for example pi/2 (in radian);
• theta: Viewing angle, the theta of the sector. % % one integer, for example 90;
• m and n: Coordinates of the focusing location, which also stands for the oriantation of the sector. % % two integers, for example 200 and 200;
• x and y: Amplitude function. % % two arrays, x which is not used in the function is the time line of y, for example 0:1:899, and y is the corresponding amplitude, for example 1:-1/899:0. To be specific, in this function, the first point of y is the middle amplitude of the sector.;

Applications:

This code is tailored for back-projection (BP) algorithms in microwave-induced thermoacoustic tomography (MITAT), with potential applications also in photoacoustic tomography (PAT). A 3D version is in development...

In MITAT BP, accounting for the ultrasonic transducer's receiving properties is crucial. During BP or related inversion algorithms, the transducer's angular characteristics must be considered. Experimental measurements determine these receiving properties, in particular the angular property, which can then serve as the amplitude function input for "generateSectorMatrix". Parameters include TA image size (siz), transducer coordinates (x0, y0), transducer's angular property (theta), TA signal receiving length (r), and image center coordinates (m, n).

Some Example:

multiplier = generateSectorMatrix([300 300], 24, 125, 150, pi/4, 200, 100, 0:1:399, 1:-1/399:0);
figure
imagesc(multiplier)
axis image
set(gca,'FontWeight','bold','FontSize',24,'FontName','Times');

multiplier = generateSectorMatrix([100 300], 125, 30, 200, pi/1.3, 300, 100, 0:100:399, 100:-100/399:0);
figure
imagesc(multiplier)
axis image
set(gca,'FontWeight','bold','FontSize',24,'FontName','Times');

multiplier = generateSectorMatrix([200 200], 150, 250, 200, pi/9, 100, 100, 0:1:5,1/(sqrt(2*pi)*1)*exp(-((0:1:5)-0).^2/(2*1^2)));
figure
imagesc(multiplier)
axis image
set(gca,'FontWeight','bold','FontSize',24,'FontName','Times');