Patent Grant
11852806
The present disclosure relates to the photodetection field, and in particular, to a method for controlling hybrid scanning based on a miniature reflecting device.
A micro-electro-mechanical systems (MEMS) mirror is a miniature reflecting device incorporating an optical MEMS technology and integrating a micro-optical reflecting mirror and an MEMS drive. The MEMS mirror can move in translational and torsional modes. A torsional MEMS mirror is mainly used for laser alignment deflection, graphical scanning, image scanning, environmental perception, and the like. As an essential key laser component for laser application, an MEMS scanning mirror has been widely applied to consumer electronics, medical, military, national defense, communication, and other fields. At present, scanning mirrors can be mainly used for LiDARs, 3D cameras, barcode scanning, laser printers, medical imaging, and the like.
Currently, most MEMS scanning devices mainly support determinant scanning in an MEMS laser imaging technology. In image perception, determinant scanning provides even image resolutions, but makes it difficult to support a wide field of view and a high resolution at the same time. In view of this, some scholars put forward circular scanning that simulates human's eyes, to support the wide field of view and the high resolution at the same time. However, during circular scanning, a scanning center needs to be artificially determined, and this makes it difficult to further improve an imaging effect.
The present disclosure discloses a method for controlling hybrid scanning based on a miniature reflecting device, to control hybrid scanning based on a miniature reflecting device (an MEMS scanning mirror), in other words, to support hybrid scanning of determinant scanning and circular scanning. Hybrid scanning supports scanning with a wide field of view and a high resolution. In addition, an automatic target positioning function is added to automatically determine a scanning center, and this improves an imaging effect.
The objective of the present disclosure is achieved by using the following technical solutions.
The method for controlling hybrid scanning based on a miniature reflecting device in the present disclosure includes: loading parameters for determinant scanning and circular scanning, setting a scanning start point, and performing determinant scanning; in a determinant scanning mode of an MEMS scanning mirror, performing low-pass filtering on received sampling data to filter an outlier in a sampling process, and performing singular value determining by calculating a quantity of singular values within a neighboring domain, to determine whether there is a valid connected domain within a scanning field of view; after completing determinant scanning, determining, as a target of interest, a valid connected domain with a maximum quantity of singular values, and obtaining a geometric center of the target of interest by calculating an average value of driving voltages corresponding to the singular values; and performing circular scanning by using the geometric center as a scanning center, determining, in a process of scanning an outermost ring, whether singular values are centrosymmetrically distributed on the ring, to fine-tune the scanning center till the singular values are centrosymmetrically distributed on the ring, performing circular scanning with a wide field of view and a high resolution based on the parameters specified for circular scanning, till the scanning is completed, and outputting a high-quality scanned image.
The method for controlling hybrid scanning based on a miniature reflecting device in the present disclosure includes the following steps:
The step 1 is implemented as follows: loading the parameters for determinant scanning and circular scanning, where the parameters for determinant scanning include a quantity M1 of rows and a quantity N1 of columns, and the parameters for circular scanning include a quantity M2 of rings and a quantity N2 of points scanned on each ring; and setting a start point of determinant scanning to be at a maximum leftward and downward deflection angle of an MEMS scanning mirror, and performing determinant scanning, where the MEMS scanning mirror gradually deflects toward the right horizontally as a voltage applied to a pin X+ gradually increases.
Preferably, the step 2 is implemented as follows: in the determinant scanning mode of the MEMS scanning mirror, performing real-time Gaussian filtering on the received data by using a 3×3 Gaussian kernel shown in a formula (1); performing Gaussian low-pass filtering to filter the outlier, in the received data, due to a random error, and performing Gaussian blurring on the received data; comparing a depth threshold p with each of differences between neighboring sampling points in data obtained after Gaussian filtering; if a difference between neighboring sampling points is greater than the depth threshold p, determining that a next sampling value is a singular value; if a difference between the singular value and data collected within a 3×3 sampling point range centered on the singular value is not greater than a connected-domain threshold q, determining that the data is also a singular value, and starting a counter to calculate a quantity λ of singular values in a connected domain; and if the counter displays that the quantity λ of singular values is greater than a difference threshold τ, determining that there is an object in the domain, and denoting the domain as the valid connected domain ξn.
The step 3 is implemented as follows: after completing determinant scanning, comparing quantities λ of singular values in valid connected domains ξ1, ξ2, ξ3, . . . ξn that are obtained in the step 2, and selecting a valid connected domain with maximum λ as the target of interest; and using a formula (2) to calculate the average value of the voltages at sampling points corresponding to the singular values in the target of interest, where X and Y are deflection voltages required at the geometric center O of the target of interest;
where x1, x2, . . . xλ respectively represent driving voltages of the singular values in the target of interest at the pin X+, and y1, y2, . . . yλ respectively represent driving voltages of the singular values in the target of interest at a pin Y+.
The step 4 is implemented as follows: performing single-ring scanning by using M2 and N2 as scanning parameters, using the geometric center O of the target of interest as the scanning center, and using, as a deflection voltage of the outermost ring, a deflection voltage value of a sample point corresponding to a singular value farthest away from the scanning center in the valid connected domain in the determinant scanning mode; after completing scanning, determining whether singular value data is centrosymmetrically distributed on the scanned ring; if the singular value data is centrosymmetrically distributed on the scanned ring, performing global circular scanning by using the original scanning center as a scanning center and using M2 and N2 as scanning conditions; or if the singular value data is not centrosymmetrically distributed on the scanned ring, using the formula (2) to fine-tune the scanning center to further correct dynamic target positioning, and performing subsequent scanning by using a fine-tuned scanning center 02, M2, and N2 as scanning conditions, till the scanning is completed; and outputting the high-quality scanned image.
In
Specific implementations of the present disclosure are described below with reference to the accompanying drawings.
The present disclosure is further described below with reference to a hardware structure shown in
As shown in
As shown in
The step 1 is implemented as follows: loading the parameters for determinant scanning in which a front target is scanned row by row and parameters for a circular scanning in which the front target is scanned ring by ring around a same scanning center, where the parameters for determinant scanning include a quantity M1 of rows and a quantity N1 of columns, and the parameters for circular scanning include a quantity M2 of rings and a quantity N2 of points scanned on each ring; and setting the start point of determinant scanning to be at a maximum leftward and downward deflection angle of the MEMS scanning mirror, as shown in
The step 2 is implemented as follows: in the determinant scanning mode of the MEMS scanning mirror, performing (S203) real-time Gaussian filtering on the received data by using a 3×3 Gaussian kernel shown in a formula (1); performing Gaussian low-pass filtering to filter the outlier, in the received data, due to a random error, and performing Gaussian blurring on the received data; comparing a depth threshold p with each of differences between neighboring sampling points in data obtained after Gaussian filtering; if a difference between neighboring sampling points is greater than the depth threshold p, determining that a next sampling value is a singular value (S204), and starting (S205) a counter to calculate a quantity λ of singular values in a connected domain; if a difference between the singular value and data collected within a 3×3 sampling point range centered on the singular value is not greater than a connected-domain threshold q (S207), determining that the data is also a singular value, and increasing (S208) a value of the counter by 1; and if the counter displays that the quantity λ of singular values is greater than a difference threshold τ (S210), determining that there is an object in the domain, storing the value of the counter (S211), and denoting the domain as the valid connected domain ξn.
The step 3 is implemented as follows: after completing determinant scanning (S212), comparing quantities λ of singular values in valid connected domains ξ1, ξ2, ξ3, . . . ξn that are obtained in the step 2, and selecting a valid connected domain with maximum λ as the target of interest; and using a formula (2) to calculate the average value of the voltages at sampling points corresponding to the singular values in the target of interest, where X and Y are deflection voltages required at the geometric center O of the target of interest (S213);
where x1, x2, . . . xλ respectively represent driving voltages of the singular values in the target of interest at the pin X+, and y1, y2, . . . yλ respectively represent driving voltages of the singular values in the target of interest at a pin Y+.
The step 4 is implemented as follows: performing circular scanning by using M2 and N2 as scanning parameters, and the geometric center O of the target of interest as the scanning center, where circular scanning is specifically performed from outside to inside, as shown in
The objectives, technical solutions, and beneficial effects of the present disclosure are further described in detail in the foregoing embodiments. It should be understood that the foregoing descriptions are merely specific embodiments of the present disclosure, but are not intended to limit the protection scope of the present disclosure. Any modification, equivalent replacement, improvement, or the like made within the spirit and principle of the present disclosure shall fall within the protection scope of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202010091134.4 | Feb 2020 | CN | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 20120307211 | Hofmann | Dec 2012 | A1 |
| 20160238834 | Erlich | Aug 2016 | A1 |
| 20180059221 | Slobodyanyuk | Mar 2018 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20210255455 A1 | Aug 2021 | US |
