A microscopic imaging method of phase contrast and differential interference contrast based on the transport of intensity equation

A microscopic imaging method of phase contrast (PC) and differential interference contrast (DIC) based on the transport of intensity equation (TIE) is characterized in that the steps are as follows:

• step 1, three intensity images are acquired along the optical axis, i.e., acquire three intensity images along the optical axis, which are positive defocus image Iz-P, infocus image I0, negative defocus image Iz-N;
• the first-order axial differentiation ∂I/∂z of the intensity I can be obtained using numerical difference estimation
• ∂
• I
• ∂
• z
• =
• I
• z
• -
• P
• -
• I
• z
• -
• N
• d
• ⁢
• z
• where dz is the distance between the positive defocus image Iz-P and the negative defocus image Iz-N in the axial direction z;
• step 2, obtain the quantitative phase image based on the TIE, that is, the quantitative phase is obtained by substituting the first-order axial differentiation ∂I/∂z obtained in step 1 into TIE;
• step 3, solve TIE in the differential interference contrast imaging mode, i.e., using the quantitative phase image obtained in step 2 to obtain the intensity image DIC(x,y) in the differential interference contrast imaging mode based on the DIC imaging theory;
• step 4, solve the phase transfer function in the phase contrast imaging mode, and solve the intensity image in the phase contrast imaging mode, i.e., use the quantitative phase image obtained in step 2 to obtain the intensity image IPC-A(u) by the annular phase contrast method and the intensity image IPC-B(u) using the phase contrast of apodization method based on the PC imaging theory.