Millimeter wave probe and human skin imaging implementation method thereof

Abstract

A millimeter wave probe and a method for realizing human skin imaging thereof use a 94GHz stepped rectangular cone dielectric rod antenna as a detection probe, and use a 94GHz millimeter wave signal source to excite and measure the skin to be tested, thereby obtaining S parameters, that is, S in the working frequency band. 11 The parameter resonance point amplitude is used to establish a data matrix and perform matrix fusion processing to achieve skin imaging. The present invention utilizes the electromagnetic properties of the skin and uses a certain millimeter wave probe for excitation. Different reflection characteristics can be used for discrimination.

Description

Technical Field

[0001] The present invention relates to a technology in the field of millimeter waves, and in particular to a method for imaging human skin using millimeter wave near-field technology. Background Art

[0002] Existing dermatological testing methods require high levels of technician experience and are inefficient. Biological tissue exhibits dielectric dispersion—the dielectric constant of biological tissue changes with the frequency of an alternating electric field. Different water content in skin cells and components results in different absorption and reflection of millimeter waves. This characteristic can be exploited to detect skin tissue. Summary of the Invention

[0003] In view of the above-mentioned deficiencies in the prior art, the present invention proposes a millimeter wave probe and a method for realizing human skin imaging thereof, which utilizes the electromagnetic properties of the skin and adopts a certain millimeter wave probe for excitation, and can distinguish according to different reflection characteristics.

[0004] The present invention is achieved through the following technical solutions:

[0005] The present invention relates to a method for realizing human skin imaging, which adopts a 94GHz stepped rectangular cone dielectric rod antenna as a detection probe, and uses a 94GHz millimeter wave signal source to excite and measure the skin to be tested, thereby obtaining S parameters, that is, S in the working frequency band. 11 The parameter resonance point amplitude is used to achieve skin imaging by establishing a data matrix and performing matrix fusion processing.

[0006] For the measurement, preferably, the 110 GHz vector network analyzer is first calibrated using a rectangular waveguide interface, and then a rectangular tapered dielectric rod probe is connected to the calibration port. The probe is then used to contact the gridded skin to be measured to obtain S parameters.

[0007] The data matrix includes: S at different positions 11 The frequency matrix of the minimum value and the S of the corresponding position 11 The amplitude of the minimum value, the element position of the matrix preferably corresponds to the actual detection position.

[0008] The matrix fusion process is to construct the data measured at multiple different positions into a frequency matrix and an amplitude matrix according to the measurement orientation, and fuse the two matrices based on the reference value to obtain a fusion matrix Y, in which each element value is: Where: b is the weight, which indicates the influence of the frequency difference data on the result; Δf ij and ΔS ij are the differences between each element in the frequency matrix and the amplitude matrix and the frequency reference value and the amplitude reference value respectively; Δfmax and ΔS max are the maximum values of the frequency difference and amplitude difference, respectively.

[0009] The fusion is achieved by, but not limited to, normalized weighting.

[0010] The reference value is: select a data point from another calibration sample as the reference value, the frequency is recorded as f0, S 11 The amplitude is recorded as S0.

[0011] The skin imaging is to normalize each element in the fused matrix to the range of [0, 255], that is, grayscale; and realize imaging according to the position of each matrix.

[0012] The present invention relates to a detection probe for implementing the above method, which is a 94GHz rectangular cone dielectric rod antenna, specifically comprising: a cross-section, a radiation tip and a matching tip, wherein: the cross-section is a rectangular parallelepiped structure, and the two ends of the cross-section respectively adopt a stepped structure to transition to the radiation tip and the matching tip.

[0013] Technical Effects

[0014] The 94GHz stepped rectangular cone dielectric rod antenna probe utilizes a stepped impedance matching structure, improving upon the rectangular waveguide probe. It offers advantages such as low sidelobes and high radiated power. Furthermore, the probe's reduced contact area with the skin enables detection of smaller tumors. This improved probe is most sensitive to frequency offset information when measuring different samples, achieving performance improvements of 25% and 212.5% higher than conventional rectangular and circular cone probes, respectively, in the 94GHz frequency band. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the detection probe of the present invention;

[0016] In the figure: cross-section 1, radiating tip 2, matching tip 3, rectangular waveguide 4;

[0017] Figure 2 Schematic diagram of the frequency of the embodiment;

[0018] Figure 3 Schematic diagram of imaging effect of the embodiment;

[0019] In the figure: (a) is a skin model diagram, in which the light-colored area is the sample calibration area, and the dark-colored part in the middle is the area to be tested. DETAILED DESCRIPTION

[0020] like Figure 1As shown, a detection probe involved in this embodiment is a 94GHz rectangular cone dielectric rod antenna, specifically including: a cross-section 1, a radiating tip 2 and a matching tip 3, wherein: the cross-section is a rectangular parallelepiped structure, and the two ends of the cross-section respectively use a stepped structure 5 to transition to the radiating tip 2 and the matching tip 3.

[0021] The detection probe is made of high-resistance silicon with a dielectric constant of 11.9.

[0022] like Figure 2 As shown, the cross-sectional size of the cross-sectional section 1 is 1 mm×0.6 mm.

[0023] The cross-sectional dimensions of the matching tip and the radiating tip are 0.5 mm×0.6 mm.

[0024] The cross-sectional dimensions of the stepped structure are 0.75 mm×0.6 mm.

[0025] The specific dimensions of the rectangular conical dielectric rod antenna in this embodiment are:

[0026]

[0027] This embodiment is based on the human skin imaging implementation method of the above detection probe, using a 94GHz rectangular cone dielectric rod antenna as the detection probe, using a 94GHz millimeter wave signal source to excite and measure the skin to be tested, and obtaining the S parameter, that is, S in the working frequency band. 11 The parameter resonance point amplitude is used to achieve skin imaging by establishing a data matrix and performing matrix fusion processing. The specific steps include:

[0028] Step 1) Use a vector network analyzer to calibrate the WR10 rectangular waveguide port. The specific operation and parameters are as follows: After setting the calibration frequency range of the vector network analyzer host to 90GHz-105GHz, and setting the number of measurement points and the intermediate frequency bandwidth, use the OSM single-port calibration method to terminate the waveguide calibration components at the network port: offset short (OffsetShort), short (Short), and match (matching device). After calibration, terminate the short-circuit calibration component. 11 The amplitude can fluctuate within the range of 0±0.01dB.

[0029] Step 2) Connect the stepped rectangular cone dielectric rod probe to the vector network analyzer port and place the probe on the skin area

[0030] Step 3) Follow Figure 3 (b) The probe position is moved in the area shown in Figure 2. Each time a sampling point is moved, S is saved. 11 Data information, to obtain the S parameter matrix. The data matrix includes: S at different positions 11The frequency matrix of the minimum value and the S of the corresponding position 11 The amplitude of the minimum value, the element position of the matrix preferably corresponds to the actual detection position.

[0031] The above steps measure the calibration skin sample and the skin sample to be tested respectively to obtain two sets of data.

[0032] Compare the matrix results of the measured calibration sample skin with the skin to be tested, and image the two-dimensional plane comparison data. The specific operations and parameters are as follows: Process the matrix obtained in the previous step: Construct the data measured at multiple different positions into frequency matrix and amplitude matrix according to the measurement orientation, calculate the two matrices based on the reference value, and obtain the fusion matrix Y, in which each element value is: Where: b is the weight, which indicates the influence of the frequency difference data on the result; Δf ij and ΔS ij are the differences between each element in the frequency matrix and the amplitude matrix and the frequency reference value and the amplitude reference value respectively; Δf max and ΔS max are the maximum values of the frequency difference and amplitude difference, respectively.

[0033] Data imaging: Use MATLAB to convert the Y matrix into an image. Each data point in the Y matrix can generate a 32×32 pixel square area at its position. The grayscale of the area is determined by the corresponding position data in the matrix. Finally, Gaussian filtering is used to filter out the high-frequency components in the image.

[0034] After specific actual experiments, the weight factor b is set to 0.4, and the Y matrix is obtained:

[0035] The result is shown in the figure Figure 3 As shown in (C): The highlighted area in the center of the image indicates the location of abnormal skin, so it can be determined that the dielectric rod probe can effectively compare skin abnormalities.

[0036] The skin model was tested using traditional rectangular cone dielectric rods, circular dielectric rods, and the improved stepped rectangular cone dielectric rod proposed in this invention. The resonance point locations were found and the resonance points S of the test skin and the sample skin were accurately measured. 11 The test results of three different dielectric rod probes are summarized as follows:

[0037]

[0038]

[0039] As can be seen from the above table, compared with the existing technology, the probe design of this device is 25% and 212.5% higher than the traditional rectangular cone probe and circular cone probe, and the imaging algorithm is simple and the imaging speed is fast.

[0040] The above-mentioned specific implementation can be partially adjusted in different ways by those skilled in the art without departing from the principles and purpose of the present invention. The scope of protection of the present invention shall be based on the claims and shall not be limited by the above-mentioned specific implementation. All implementation schemes within its scope shall be subject to the constraints of the present invention.

Claims

1. A method for realizing human skin imaging, characterized in that: A 94GHz stepped rectangular cone dielectric rod antenna is used as the detection probe, and a 94GHz millimeter wave signal source is used to excite and measure the skin to be tested to obtain the S parameter, that is, S in the working frequency band. 11 The amplitude of the parameter resonance point is used to achieve skin imaging by establishing a data matrix and performing matrix fusion processing; The measurement is performed by first calibrating the 110 GHz vector network analyzer using a rectangular waveguide interface. Then, a rectangular tapered dielectric rod probe is connected to the calibration port. The probe is then used to contact a gridded area of the skin to be measured to obtain S parameters. The data matrix includes: S at different positions 11 The frequency matrix of the minimum value and the S of the corresponding position 11 The amplitude of the minimum value, the element position of the matrix corresponds to the actual detection position; The rectangular cone dielectric rod antenna specifically comprises a cross section, a radiation tip and a matching tip, wherein the cross section is a rectangular parallelepiped structure, and both ends of the cross section respectively adopt a stepped structure to transition to the radiation tip and the matching tip.

2. The method for realizing human skin imaging according to claim 1, wherein: The matrix fusion process is to construct the data measured at multiple different positions into a frequency matrix and an amplitude matrix according to the measurement orientation, and fuse the two matrices based on the reference value to obtain a fusion matrix Y, in which each element value is: , where: b is the weight, which indicates the influence of frequency difference data on the results; and are the differences between each element in the frequency matrix and the amplitude matrix and the frequency reference value and the amplitude reference value respectively; and are the maximum values of the frequency difference and amplitude difference, respectively.

3. The method for realizing human skin imaging according to claim 1 or 2, wherein: The fusion is achieved by using normalized weighting.

4. The method for realizing human skin imaging according to claim 2, wherein: The reference value is: select a data point from another calibration sample as the reference value, the frequency is recorded as f0, S 11 The amplitude is recorded as S0.

5. The method for realizing human skin imaging according to claim 1, wherein: The skin imaging is to normalize each element in the fused matrix to the range of [0, 255], that is, grayscale; and realize imaging according to the position of each matrix.

6. A detection probe, characterized in that: The method for implementing human skin imaging as described in any one of claims 1 to 5 is a 94GHz rectangular cone dielectric rod antenna, specifically comprising: a cross-section, a radiating tip and a matching tip, wherein: the cross-section is a rectangular parallelepiped structure, and the two ends of the cross-section respectively adopt a stepped structure to transition to the radiating tip and the matching tip.

Images