Method, device and medium for step size calibration of two-dimensional scanning module in scanning light field imaging system

A method for step size calibration of a two-dimensional scanning module in a scanning light field imaging system, comprising:

• performing two-dimensional scanning on a sample to be measured, with N scans in a horizontal direction and N scans in a vertical direction, totaling N*N scans, collecting N2 sheets of two-dimensional raw scanning light field data, and rearranging into four-dimensional phase space data to obtain multi-view rearranged images;
• selecting middle views of all views in the multi-view rearranged images to obtain non-scanned central view sub-images;
• calculating a sub-pixel displacement matrix of all non-scanned central view sub-images relative to a first non-scanned central view sub-image, where the sub-pixel displacement matrix characterizes pixel offsets between images caused by two-dimensional scanning;
• calculating an average displacement quantity according to the sub-pixel displacement matrix, and calculating a step size adjustment coefficient according to the average displacement quantity;
• and
• updating a correct scanning step size according to the step size adjustment coefficient;
• wherein the calculating the sub-pixel displacement matrix of all non-scanned central view sub-images relative to the first non-scanned central view sub-image specifically comprises:
• calculating cross-correlations between all of the non-scanned central view sub-images and the first non-scanned central view sub-image respectively, wherein a maximum value of the cross-correlations is a relative displacement of two images;
• C
• i
• ,
• j
• (
• m
• ,
• n
• )
• =
• ∑
• x
• ∑
• y
• CV
• ⁡
• (
• i
• ,
• j
• ,
• x
• +
• m
• ,
• y
• +
• n
• )
• ⁢
• CV
• ⁡
• (
• 1
• ,
• 1
• ,
• x
• ,
• y
• )
• ,
• y
• ∈
• [
• 1
• ,
• h
• ]
• ,
• x
• ∈
• [
• 1
• ,
• w
• ]
• s
• ⁡
• (
• i
• ,
• j
• )
• =
• argmax
• ⁢
• C
• i
• ,
• j
• (
• m
• ,
• n
• )
• ,
• i
• ∈
• [
• 1
• ,
• N
• ]
• ,
• j
• ∈
• [
• 1
• ,
• N
• ]
• wherein i and j indicate coordinates of the two-dimensional scanning, N indicates number of scans;
• x and y indicate two-dimensional pixel coordinates of an image, m and n indicate two-dimensional cross-correlation calculation variables;
• h and w indicate a pixel height and pixel width of the multi-view rearranged image, CV(·) indicates the non-scanned central view sub-image, and S(i, j) indicates the sub-pixel displacement matrix;
• an average displacement quantity in an X-axis direction is:
• X
• =
• S
• [
• N
• ,
• :
• ,
• 1
• ]
• -
• S
• [
• 1
• ,
• :
• ,
• 1
• ]
• N
• ⁡
• (
• N
• -
• 1
• )
• wherein S[N,:,1] indicates an x displacement of a N-th column of the sub-pixel displacement matrix, S[1,:,1] indicates an x displacement of a 1st column of the sub-pixel displacement matrix;
• an average displacement quantity in a Y-axis direction is:
• Y
• =
• S
• [
• :
• ,
• N
• ,
• 2
• ]
• -
• S
• [
• :
• ,
• 1
• ,
• 2
• ]
• N
• ⁡
• (
• N
• -
• 1
• )
• wherein S[:,N,2] indicates a y displacement of a N-th row of the sub-pixel displacement matrix, S[:,1,2] indicates the y displacement of a 1st row of the sub-pixel displacement matrix;
• a step size adjustment coefficient KX in the X-axis direction is:
• KX
• =
• 1
• N
• *
• X
• wherein X indicates the average displacement quantity in the X-axis direction;
• and
• a step size adjustment coefficient KY in the Y-axis direction is:
• KY
• =
• 1
• N
• *
• Y
• wherein Y indicates the average displacement quantity in the Y-axis direction.