Single-pixel imaging device and method based on led array light source and light scattering effect
By using LED array light source and light scattering effect in single-pixel imaging technology, the problem of traditional technology relying on reflective screens is solved, and single-pixel imaging is realized without reflective screens, expanding the application range.
Patent Information
- Application Number
- CN202411817579.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-11
- Publication Date
- 2025-03-18
AI Technical Summary
Traditional single-pixel imaging technology relies on reflective screens, limiting its application scenarios.
Using a single pixel imaging device based on the LED array light source and the light scattering effect, the light source driving unit is controlled to drive the array light source to emit structured light through the structured light generation unit, and the light is irradiated on the target object and scattered through the scattering medium, and imaging of the target object is achieved using a light intensity detector and a post-processing unit.
No reflective screen is required, which greatly expands the application range of single-pixel imaging and enables imaging in non-line-of-sight scenarios.
Smart Images
Figure CN119643509A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of imaging detection technology, and in particular relates to a single-pixel imaging device and method based on an LED array light source and light scattering effect in a non-line-of-sight scenario. Background Art
[0002] Single-pixel imaging is an imaging method that uses structured light illumination at the illumination end and uses a single-pixel light intensity detector at the detection end to collect and calculate signals. When the illumination structure light field changes, the corresponding change in the object light intensity reflects the degree of correlation between the illumination structure light field and the object's morphological information. By continuously changing the illumination structure light field and accumulating the correlation information at the single-pixel detection end, the object can be imaged by solving the correlation information.
[0003] Traditional single-pixel imaging requires a single-pixel detector to measure the intensity of light reflected from a scene. However, in reality, there may be no object such as a reflective screen near the object to be detected to form a reflective light path, which severely limits the application scenarios of traditional single-pixel imaging. Summary of the invention
[0004] In order to solve the above-mentioned technical problem of the existing single-pixel imaging technology relying on a reflective screen, the present invention proposes a single-pixel imaging device and method based on an LED array light source and a light scattering effect, which does not require a reflective screen and greatly expands the application scope of single-pixel imaging to solve the above-mentioned problems existing in the prior art.
[0005] To achieve the above object, the present invention provides a single-pixel imaging device based on an LED array light source and a light scattering effect, comprising:
[0006] A transmitting end and a receiving end, wherein the transmitting end includes a structured light generating unit, a light source driving unit and an array light source connected in sequence, and the receiving end includes an optical pre-processing unit, a light intensity detector and a post-processing unit connected in sequence;
[0007] Among them, the light source driving unit is controlled by the structured light generating unit to drive the array light source to emit structured light, the structured light is irradiated on the target object to be measured and scattered by the scattering medium, the scattered light is optically preprocessed by the optical preprocessing unit, the optically preprocessed light is detected by the light intensity detector to obtain light intensity information, and the light intensity information is analyzed by the post-processing unit to obtain the imaging of the target object.
[0008] Optionally, the array light source is an ultraviolet LED array light source.
[0009] Optionally, the scattering medium includes air, atmospheric molecules and suspended particles in space.
[0010] Optionally, the optical preprocessing unit adopts a focusing lens.
[0011] In order to better achieve the above technical objectives, the present invention also provides a single pixel imaging method based on an LED array light source and a light scattering effect, comprising:
[0012] The structured light generating unit controls the light source driving unit to drive the array light source to emit structured light according to the Hadamard matrix;
[0013] The structured light is irradiated on the target object to be measured and scattered by the scattering medium. The scattered light is optically preprocessed by the optical preprocessing unit, and the optically preprocessed light is detected by the light intensity detector to obtain light intensity information. The light intensity information is analyzed by the post-processing unit to obtain an image of the target object.
[0014] Optionally, the Hadamard matrix is constructed by a recursive algorithm.
[0015] Optionally, the process of controlling the light source driving unit to drive the array light source to emit structured light includes:
[0016] Reshaping each row vector in the Hadamard matrix to obtain a sub-pattern corresponding to each row vector;
[0017] Perform differential measurement on the sub-patterns to obtain an illumination pattern, wherein the illumination pattern includes a first illumination pattern and a second illumination pattern with adjacent modulation orders and opposite patterns, wherein elements in the first illumination pattern and the second illumination pattern are 0 or 1 and satisfy:
[0018]
[0019] Among them, P m and denote the first lighting pattern and the second lighting pattern respectively, and h m represents the sub-pattern corresponding to the m-th row vector;
[0020] A modulation order is obtained according to the order of row vectors and the standard that the first illumination pattern corresponding to each row vector takes precedence over the second illumination pattern. According to the modulation order, the light source driving unit is controlled to drive the array light source to sequentially emit structured light of corresponding illumination patterns.
[0021] Optionally, the process of parsing the light intensity information by the post-processing unit includes:
[0022]
[0023] Where O represents the two-dimensional image of the target object, I m and The light intensity detector corresponding to the first illumination image and the second illumination image of the m-th sub-pattern measures the light intensity information, where the light intensity information is the number of photons, n 2 Represents the dimension of a two-dimensional image, and m represents the row vector number.
[0024] Compared with the prior art, the present invention has the following advantages and technical effects:
[0025] The present invention proposes to use LED array light sources and light scattering effects to achieve single-pixel imaging in scenes without reflective surfaces, which greatly expands the application scope of single-pixel imaging. BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:
[0027] Figure 1 is a structural diagram of a device according to an embodiment of the present invention;
[0028] Figure 2 A schematic diagram of the variation of the light intensity reaching the detector over time when single-pixel imaging is achieved by using the light scattering effect and a schematic diagram of the variation of the light intensity reaching the detector over time when single-pixel imaging is achieved by using a reflective light path according to an embodiment of the present invention;
[0029] Among them, 1. structured light generation unit; 2. light source driving unit; 3. array light source; 4. target object; 5. scattering medium; 6. optical pre-processing unit; 7. light intensity detector; 8. post-processing unit. DETAILED DESCRIPTION
[0030] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.
[0031] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.
[0032] Embodiment 1
[0033] like Figure 1 As shown, this embodiment provides a single-pixel imaging device based on an LED array light source and a light scattering effect, including: a transmitting end and a receiving end;
[0034] The transmitting end includes a structured light generating unit 1, a light source driving unit 2 and an array light source 3 connected in sequence, and the receiving end includes an optical pre-processing unit 6, a light intensity detector 7 and a post-processing unit 8 connected in sequence;
[0035] The structured light generating unit 1 controls the light source driving unit 2 to drive the array light source 3 to emit structured light according to the Hadamard matrix. The structured light is irradiated on the target object 4 and scattered by the scattering medium 5. The scattered light is optically preprocessed by the optical preprocessing unit 6. The optically preprocessed light is detected by the light intensity detector 7 to obtain light intensity information. The light intensity information is analyzed by the post-processing unit 8 to obtain an image of the target object 4.
[0036] As some embodiments, the structured light generating unit 1 may adopt a field programmable gate array FPGA.
[0037] As some embodiments, the light source driving unit 2 may adopt an LED driving circuit.
[0038] As some embodiments, the array light source 3 may be an ultraviolet LED array light source, wherein the ultraviolet LED array light source includes n rows and n columns of ultraviolet LEDs.
[0039] As some embodiments, the scattering medium 5 includes scattering media such as atmospheric molecules and suspended particles in space.
[0040] As some embodiments, the optical pre-processing unit 6 may use an optical focusing lens such as a condenser lens.
[0041] As some embodiments, the light intensity detector 7 may be a detector for measuring light intensity, such as a single photon detector.
[0042] As some embodiments, the post-processing unit 8 may be a computing device such as a computer.
[0043] As some embodiments, in the structured light generating unit 1 , the Hadamard matrix is constructed by a recursive algorithm.
[0044] As some embodiments, in the structured light generating unit 1, an illumination pattern is generated according to a Hadamard matrix, wherein each row vector of the Hadamard matrix is shaped into a sub-pattern h m , according to the sub-pattern h m The illumination patterns corresponding to the sub-patterns generated by the differential measurement, each illumination pattern corresponding to the sub-pattern includes a first illumination pattern P m and the second lighting pattern The first lighting pattern P m and the second lighting pattern The modulation order of is adjacent and the pattern is opposite, and it satisfies:
[0045]
[0046] According to the order of each row vector in the Hadamard matrix, the array light source 3 is driven by the light source driving unit 2 according to the illumination pattern to emit structured light according to the modulation order; wherein the modulation order is the top-down order of each row vector in the Hadamard matrix, and the first illumination pattern P corresponding to the sub-pattern m Priority over the second lighting pattern
[0047] The array light source 3 emits structured light to illuminate the target object 4 to be measured. The light carrying the information of the target object 4 is scattered by the scattering medium 5, converged by the optical preprocessing unit 6, and then received by the light intensity detector 7 to obtain the corresponding light intensity information.
[0048] As some embodiments, the post-processing unit 8 may calculate the light intensity information by offline processing to obtain a two-dimensional image of the target object 4 to be measured, wherein the two-dimensional image O of n×n pixel values of the target object to be measured is expressed as:
[0049]
[0050] Wherein, corresponding to the first lighting pattern P m and the second lighting pattern The light intensity detector 7 measures the number of photons, i.e., the first light intensity information and the second light intensity information, as I m and n represents the matrix dimension, and m represents the row vector number of the corresponding Hadamard matrix or the corresponding sub-pattern number.
[0051] Embodiment 2
[0052] In order to better achieve the above technical objectives, the present invention proposes a single-pixel imaging method based on an LED array light source and light scattering effect in a non-line-of-sight scenario. The specific technical solution is implemented according to the following steps:
[0053] Step 1: If Figure 1 As shown, at the transmitting end, the structured light generating unit 1 controls the light source driving unit 2 to generate structured light coding information, and the array light source 3 emits structured light.
[0054] Step 2: The structured light is irradiated onto the target object 4 and scattered by scattering media 5 such as atmospheric molecules and suspended particles in the space. The scattered light is then optically preprocessed by an optical preprocessing unit 6 and then detected by a light intensity detector 7.
[0055] Step 3: The post-processing unit 8 processes the light intensity information detected by the light intensity detector 7 to restore the image of the target object.
[0056] refer to Figure 1 The present invention proposes a single-pixel imaging device based on an LED array light source and a light scattering effect, the device comprising a structured light generation unit 1 (such as a field programmable gate array FPGA) for controlling a light source driving unit 2 (such as an LED driving circuit). The light source driving unit 2 is used to synchronously control an array light source 3 (such as an ultraviolet LED array light source with n rows and n columns) to ensure that each LED light source is lit and extinguished at the same time, so that the array light source 3 displays a structured light of an illumination pattern. The target object 4 is located within the illumination range of the array light source 3, the light intensity detector 7 (such as a single photon detector, etc.) is located behind the optical pre-processing unit 6 (such as a focusing lens, etc.), and the post-processing unit 8 (such as a computer, etc.) is used to process the data obtained by the light intensity detector 7 and solve the image of the target object.
[0057] The following describes the proposed single-pixel imaging method in detail by taking an ultraviolet LED array light source with strong scattering characteristics and an illumination structure modulated by a Hadamard matrix as an example and based on the above imaging device. The specific implementation includes the following steps:
[0058] Step 1: Assume that the array light source 3 uses an array light source of UV LEDs with n rows and n columns, a total of n 2 The light source driving unit 2 can use the LED driving chip to synchronously control the ultraviolet LED array, and the structured light generating unit 1 can use the field programmable gate array FPGA to control the driving chip.
[0059] Step 2: If single pixel imaging uses n 2 The Hadamard matrix of order is the modulation matrix. The Hadamard matrix is a binary orthogonal matrix, n 2 A Hadamard matrix of order n is a 2 ×n 2 An orthogonal matrix whose elements consist only of +1 and -1.
[0060] The construction method of Hadamard matrix is realized by recursive algorithm. Let H k Represents a 2 k Hadamard matrix of order:
[0061]
[0062] For example, the first-order Hadamard matrix is H0=[1], and the second-order Hadamard matrix is The 4th-order Hadamard matrix is Then n2 The Hadamard matrix of order is:
[0063]
[0064] The pattern displayed by the UV LED array should be composed of n 2 The Hadamard sub-pattern h is formed by shaping each row vector of the Hadamard matrix of order m For example, n 2 The row vector of the mth row of the Hadamard matrix of order is:
[0065] h(m)=[x m1 ,x m2 ,...,x mn2 ] (3)
[0066] Reshape it into a Hadamard subpattern h m , expressed as:
[0067]
[0068] The LED array can only display +1 and 0, but not -1. Therefore, in order to ensure the orthogonality of the Hadamard matrix, differential measurement is required, that is, a Hadamard sub-pattern h m It is necessary to measure two corresponding illumination patterns P with opposite modulation orders. m and P m The light intensity information is the number of photons. The opposite pattern indicates that the corresponding elements in the matrix are opposite or different. In this method, the LED light represents 1 and the LED off represents 0, and the total modulation times of the ultraviolet LED array is 2n 2 Assume that the first modulation number i corresponding to the mth sub-pattern is an odd number and (i+1) / 2=m. For the mth sub-pattern, the i-th and i+1-th
[0069]
[0070] The LED array emits a light field at a modulation rate of V=K frames / s to illuminate the object to be measured. The ultraviolet light carrying the information of the target object 4 is scattered by the scattering medium 5 and is received by the light intensity detector 7 after being converged by the optical pre-processing unit 6.
[0071] Traditional single-pixel imaging requires a single-pixel detector to measure the intensity of light reflected from a scene. Figure 2 As shown in the right figure, photons can reach the single-pixel detector in a relatively short time Δt2 according to the reflected light path. However, the present invention proposes to utilize the scattering effect of air on ultraviolet light, that is, photons can reach the single-pixel detector after one or more scatterings. Figure 2As shown in the left figure, compared with traditional single-pixel imaging, it takes a longer time Δt1 for scattered photons to reach the single-pixel detector, that is, Δt1>Δt2. Therefore, when setting the LED array modulation rate V, the following should be considered:
[0072] V<1 / Δt1 (6)
[0073] Step 3: Assume that the post-processing unit 8 uses computer offline processing, combines each illumination pattern of the LED array, and performs a fast Hadamard inverse transform on the output signal of the single-photon detector to achieve a fast correlation calculation between the output signal of the single-photon detector and the corresponding illumination pattern. The correlation algorithm is as follows:
[0074] Let the mth Hadamard subpattern be The single photon detector needs to measure the corresponding LED array lighting patterns, P m and The corresponding measured light intensity information, i.e. the number of photons, is I m and I m , the two-dimensional image O of n×n pixel values corresponding to the target object 4 to be measured can finally be expressed as:
[0075]
[0076] In non-line-of-sight scenarios, the scattering medium 5 scatters the illumination pattern carrying the object information to the detector, which is received by the detector and can be processed by the algorithm to realize imaging. At the same time, the scattering medium 5, such as atmospheric molecules, suspended particles, etc., is a common or easy-to-construct substance. When the scattering medium 5 is used, it is not necessary to use the reflector, reflective screen and other structures in its conventional single-pixel imaging, and its cost is further reduced. At the same time, there is no fixed position restriction of the reflector and reflective screen structure in the optical path. The scattering characteristics of the scattering medium 5 can scatter light to different positions for the receiver to receive, and the imaging measurement is more convenient and quick.
[0077] Based on the above scattering medium 5, the present invention makes relevant improvements to the related single pixel imaging method, wherein, based on the scattering characteristics of the scattering medium 5, the present invention designs the above series of processes, based on the modulation matrix, sets the corresponding illumination pattern, illuminates the target object 4 through the illumination pattern, propagates in the scattering medium 5, and receives the propagated light through the receiver. Since the above illumination pattern propagates through the scattering medium 5, it is received in pairs, and a fast correlation calculation can be performed. At the same time, since each illumination of the illumination pattern is different through the switching state of the LED as the elements in different patterns, the element values of the matrix can be effectively distinguished after scattering, and even the scattering characteristics of the scattering medium 5 will not affect the final light receiving result of the receiver. At the same time, the present invention also mentions that photons can reach the detection end after being scattered once or multiple times by the scattering medium 5, so the LED array modulation rate in the present invention patent needs to consider formula (6) to be more suitable for the scattering medium 5.
[0078] The present invention provides a single-pixel imaging device and method based on an LED array light source and light scattering effect for use in non-line-of-sight scenarios. The method has no requirements on the positional relationship between the array light source, the target object, and the light intensity detector. The method mainly utilizes the scattering characteristics of light, so there is no need to specially construct a reflective light path, which allows single-pixel imaging to be better applied to non-line-of-sight scenarios.
[0079] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.
Claims
1. A single pixel imaging device based on LED array light source and light scattering effect, characterized in that: include: A transmitting end and a receiving end, wherein the transmitting end includes a structured light generating unit, a light source driving unit and an array light source connected in sequence, and the receiving end includes an optical pre-processing unit, a light intensity detector and a post-processing unit connected in sequence; Among them, the light source driving unit is controlled by the structured light generating unit to drive the array light source to emit structured light, the structured light is irradiated on the target object to be measured and scattered by the scattering medium, the scattered light is optically preprocessed by the optical preprocessing unit, the optically preprocessed light is detected by the light intensity detector to obtain light intensity information, and the light intensity information is analyzed by the post-processing unit to obtain the imaging of the target object.
2. The device according to claim 1, characterized in that The array light source adopts an ultraviolet LED array light source.
3. The device according to claim 1, characterized in that The scattering medium includes air, atmospheric molecules and suspended particles in the space.
4. The device according to claim 1, characterized in that The optical pre-processing unit adopts a condenser lens.
5. An imaging method corresponding to the single-pixel imaging device based on an LED array light source and light scattering effect according to any one of claims 1 to 4, characterized in that: include: The structured light generating unit controls the light source driving unit to drive the array light source to emit structured light according to the Hadamard matrix; The structured light is irradiated on the target object to be measured and scattered by the scattering medium. The scattered light is optically preprocessed by the optical preprocessing unit, and the optically preprocessed light is detected by the light intensity detector to obtain light intensity information. The light intensity information is analyzed by the post-processing unit to obtain an image of the target object.
6. The method according to claim 5, characterized in that The Hadamard matrix is constructed by a recursive algorithm.
7. The method according to claim 5, characterized in that The process of controlling the light source driving unit to drive the array light source to emit structured light includes: Reshaping each row vector in the Hadamard matrix to obtain a sub-pattern corresponding to each row vector; Perform differential measurement on the sub-patterns to obtain an illumination pattern, wherein the illumination pattern includes a first illumination pattern and a second illumination pattern with adjacent modulation orders and opposite patterns, wherein elements in the first illumination pattern and the second illumination pattern are 0 or 1 and satisfy: Among them, P m and denote the first lighting pattern and the second lighting pattern respectively, and h m represents the sub-pattern corresponding to the m-th row vector; A modulation order is obtained according to the order of row vectors and the standard that the first illumination pattern corresponding to each row vector takes precedence over the second illumination pattern. According to the modulation order, the light source driving unit is controlled to drive the array light source to sequentially emit structured light of corresponding illumination patterns.
8. The method according to claim 5, characterized in that The process of parsing the light intensity information through the post-processing unit includes: Where O represents the two-dimensional image of the target object, I m and The light intensity detector corresponding to the first illumination image and the second illumination image of the m-th sub-pattern measures the light intensity information, where the light intensity information is the number of photons, n 2 Represents the dimension of a two-dimensional image, and m represents the row vector number.