A Multi-Spectral Image Acquisition System and Processing Method Based on AOTF

Abstract

The present application provides a multi-spectral image acquisition system and a processing method based on an AOTF. The multi-spectral image acquisition system based on an AOTF includes: a plurality of acquisition modules and a control module. The plurality of acquisition modules include an AOTF unit and an imaging unit connected to the output end of the AOTF unit. The AOTF unit is used to control the incident light with a set wavelength to pass through, and the set wavelength is adjustable within the adjustment range of the AOTF unit; different AOTF units have different adjustment ranges. The imaging unit is used to capture images at a set frame rate. The image input end of the control module is connected to the output ends of the plurality of imaging units, and the first output end of the control module is connected to the control ends of the plurality of AOTF units and the control ends of the plurality of imaging units. Through the above structure, by using a plurality of AOTF units with different adjustment ranges, the wavelength range of the collected spectrum is broadened, the image acquisition rate is increased, and the processing time is saved.

Description

Technical Field

[0001] The present disclosure generally relates to the field of acquisition and processing of multispectral images, and particularly to a multispectral image acquisition system and processing method based on AOTF. Background Art

[0002] With the continuous innovation of spectral imaging technology, imaging spectrometers have started to develop towards multi-band, wide spectral coverage range, and high resolution. The spectral wavelength ranges collected by existing imaging spectrometers are generally narrow, and the acquisition rate is low. The spectral range of the spectrometer determines the imaging quality of the target to be measured in different environments, which in turn affects the detection ability of the subsequent target analysis system. Summary of the Invention

[0003] In view of the above-mentioned defects or deficiencies in the prior art, it is desirable to provide a multispectral image acquisition system and processing method based on AOTF that can solve the above technical problems.

[0004] The first aspect of the present application provides a multispectral image acquisition system based on AOTF, including:

[0005] A plurality of acquisition modules, each acquisition module including an AOTF unit and a shooting unit connected to the output end of the AOTF unit; the AOTF unit is used to control the incident light with a set wavelength to pass through, and the set wavelength is adjustable within the adjustment range of the AOTF unit; different AOTF units have different adjustment ranges; the shooting unit is used to shoot images at a set frame rate;

[0006] A control module, the image input end of the control module is connected to the output ends of a plurality of shooting units, and the first output end of the control module is connected to the control ends of a plurality of AOTF units and the control ends of a plurality of shooting units;

[0007] The control module is configured to:

[0008] Receive a target wavelength and a target frame rate;

[0009] Adjust the set wavelength corresponding to the target AOTF unit to the target wavelength, where the target AOTF unit is: the AOTF unit whose adjustment range among all the AOTF units includes the target wavelength;

[0010] Adjust the set frame rate corresponding to the target shooting unit to the target frame rate, where the target shooting unit is: the shooting unit connected to the target AOTF unit;

[0011] Receive the image taken by the target shooting unit.

[0012] According to the technical solution provided by the embodiment of the present application, an upper computer is connected to the image output end of the control module, and the output end of the upper computer is connected to the information input end of the control module;

[0013] The upper computer is configured to:

[0014] Send the target wavelength and the target frame rate;

[0015] Receive and display the image sent by the control module.

[0016] According to the technical solution provided by the embodiment of the present application, the AOTF unit is used to receive different radio frequency driving frequencies, and then adjust the set wavelength within the adjustment range of the AOTF unit;

[0017] The control module is further configured to:

[0018] Convert the target wavelength into a corresponding radio frequency driving frequency;

[0019] Send the radio frequency driving frequency to the target AOTF unit, and adjust the set wavelength corresponding to the target AOTF unit to the target wavelength.

[0020] According to the technical solution provided by the embodiment of the present application,

[0021] The control module is further configured to: receive the first signal sent by the target AOTF unit, and when it is determined that the first signal is at a low level, send the radio frequency driving frequency to the target AOTF unit;

[0022] The target AOTF unit is further configured to: when receiving the radio frequency driving frequency, raise the first signal;

[0023] The control module is further configured to: when receiving the image captured by the target imaging unit, send a second signal to the target AOTF unit;

[0024] The target AOTF unit is further configured to: when receiving the second signal, lower the first signal.

[0025] According to the technical solution provided by the embodiment of the present application, an optical system is provided at the input ends of multiple AOTF units, a measured target is provided in front of the optical system, and the optical system is used to compress the light incident angle of the measured target into a set field of view angle range.

[0026] The second aspect of the present application provides a multi-spectral image acquisition and processing method based on AOTF, which adopts a multi-spectral image acquisition system based on AOTF as described above. The multi-spectral image acquisition and processing method based on AOTF includes the following steps:

[0027] Receive the target wavelength and the target frame rate;

[0028] Adjust the set wavelength corresponding to the target AOTF unit to the target wavelength, where the target AOTF unit is: the AOTF unit whose adjustment range includes the target wavelength among all the AOTF units;

[0029] Adjust the set frame rate corresponding to the target imaging unit to the target frame rate, where the target imaging unit is: the imaging unit connected to the target AOTF unit;

[0030] Receive the image captured by the target imaging unit

[0031] According to the technical solution provided in the embodiments of the present application, the following steps are further included:

[0032] Convert the target wavelength into a corresponding radio frequency drive frequency;

[0033] Send the radio frequency drive frequency to the target AOTF unit, and adjust the set wavelength corresponding to the target AOTF unit to the target wavelength.

[0034] According to the technical solution provided in the embodiments of the present application, the following steps are further included:

[0035] Receive the first signal sent by the target AOTF unit. When it is determined that the first signal is at a low level, send the radio frequency drive frequency to the target AOTF unit; when the target AOTF unit receives the radio frequency drive frequency, raise the first signal;

[0036] When receiving the image captured by the target imaging unit, send a second signal to the target AOTF unit; when the target AOTF unit receives the second signal, lower the first signal.

[0037] The beneficial effects of the present application are as follows: Based on the technical solution provided in the present application, it includes multiple acquisition modules and a control module. The acquisition module includes an AOTF unit and an imaging unit connected to the output end of the AOTF unit. Different AOTF units have different adjustment ranges. During use, the control module receives the target wavelength and the target frame rate, determines the corresponding target AOTF unit according to the target wavelength, and adjusts the set wavelength of the target AOTF unit to the target wavelength; adjusts the set frame rate corresponding to the imaging unit connected to the target AOTF unit to the target frame rate; the imaging unit acquires an image with a specific wavelength passing through the AOTF unit and sends the captured image to the control module. Through the above structure, by using multiple AOTF units with different adjustment ranges, the wavelength range of the collected spectrum is widened, the image acquisition rate is increased, and the processing time is saved. Brief Description of the Drawings

[0038] Other features, objects, and advantages of the present application will become more apparent from the following detailed description of non - limiting embodiments read in conjunction with the accompanying drawings:

[0039] Figure 1 It is a schematic structural diagram of a multi - spectral image acquisition system based on AOTF in the present application;

[0040] Figure 2 It is a schematic diagram of the working state of the control module of a multi - spectral image acquisition system based on AOTF in the present application.

[0041] In the figure: 1. Acquisition module; 2. AOTF unit; 3. Shooting unit; 4. Control module; 5. Host computer; 6. Optical system; 7. Measured target. Detailed Embodiments

[0042] The present application will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the related invention and not for limiting the invention. Additionally, it should be noted that for the sake of description, only parts related to the invention are shown in the drawings.

[0043] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and embodiments.

[0044] Embodiment 1

[0045] Please refer to Figure 1 which is a schematic structural diagram of a multi - spectral image acquisition system based on AOTF provided by the present application, including:

[0046] A plurality of acquisition modules 1, each of the acquisition modules 1 includes an AOTF unit 2 and a shooting unit 3 connected to the output end of the AOTF unit 2; the AOTF unit 2 is used to control the incident light with a set wavelength to pass through, and the set wavelength is adjustable within the adjustment range of the AOTF unit 2; different AOTF units 2 have different adjustment ranges; the shooting unit 3 is used to shoot images at a set frame rate;

[0047] A control module 4, the image input end of the control module 4 is connected to the output ends of the plurality of shooting units 3, and the first output end of the control module is connected to the control ends of the plurality of AOTF units 2 and the control ends of the plurality of shooting units 3;

[0048] The control module 4 is configured to:

[0049] Receive the target wavelength and the target frame rate;

[0050] Adjust the set wavelength of the target AOTF unit 2 to the target wavelength, where the target AOTF unit 2 is: the AOTF unit 2 among all the adjustment ranges of the AOTF units 2 that includes the target wavelength;

[0051] Adjust the set frame rate of the target imaging unit 3 to the target frame rate, where the target imaging unit 3 is: the imaging unit 3 connected to the target AOTF unit 2;

[0052] Receive the image captured by the target imaging unit 3.

[0053] Specifically, the AOTF unit 2 is an acousto-optic tunable filter. As a spectroscopic device, the acousto-optic tunable filter has the characteristics of small volume, light weight, fast scanning speed, no moving parts, good shock resistance, etc. At the same time, it supports a wider spectral range, larger incident aperture and field of view angle, and has greater advantages in multispectral imaging applications;

[0054] Specifically, the AOTF unit 2 is composed of an acousto-optic crystal, an ultrasonic transducer, and an acoustic absorption device, and works based on the acousto-optic diffraction principle; the ultrasonic transducer converts the signal sent by the radio frequency driver into an ultrasonic signal and transmits it into the acousto-optic crystal. The ultrasonic wave causes a periodic change in the refractive index of the crystal to form an ultrasonic grating. When the incident light irradiates the grating, Bragg diffraction occurs, and the wavelength of the diffracted light corresponds to the radio frequency driving frequency. If the incident light has a more complex spectral composition, that is, it contains light of multiple wavelength forms, by changing the radio frequency driving frequency, the wavelength of the diffracted light can be changed, thereby achieving the purpose of spectroscopy;

[0055] Working principle: During use, the control module 4 receives the target wavelength and the target frame rate, determines the corresponding target AOTF unit 2 according to the target wavelength, and adjusts the set wavelength of the target AOTF unit 2 to the target wavelength; adjusts the set frame rate of the imaging unit 3 connected to the target AOTF unit 2 to the target frame rate; the imaging unit 3 acquires the image with a specific wavelength passing through the AOTF unit 2 and sends the captured image to the control module 4; through the above structure, by using multiple AOTF units 2 with different adjustment ranges, the wavelength range of the collected spectrum is widened, the image acquisition rate is increased, and the processing time is saved.

[0056] In some embodiments, an upper computer 5 is connected to the image output end of the control module 4, and the output end of the upper computer 5 is connected to the information input end of the control module 4;

[0057] The upper computer 5 is configured to:

[0058] Send the target wavelength and the target frame rate;

[0059] Receive and display the image sent by the control module 4.

[0060] Specifically, the host computer 5 is a computer that can directly issue control commands;

[0061] Specifically, the host computer 5 is used to send the target wavelength and the target frame rate, and at the same time receive and display the image sent by the control module 4;

[0062] Specifically, as Figure 2 shown, the host computer 5 is connected to the image output end of the control module through a USB3.0 interface, and the USB3.0 interface transmits the image sent by the control module 4; the host computer sends the target wavelength and the target frame rate through a serial port, and after the control module 4 receives the target wavelength and the target frame rate, it feeds back to the host computer;

[0063] In some embodiments, the AOTF unit 2 is used to receive different radio frequency driving frequencies, and then adjust the set wavelength within the adjustment range of the AOTF unit 2;

[0064] The control module 4 is further configured to:

[0065] Convert the target wavelength into a corresponding radio frequency driving frequency;

[0066] Send the radio frequency driving frequency to the target AOTF unit 2, and adjust the set wavelength corresponding to the target AOTF unit 2 to the target wavelength.

[0067] Specifically, the photographing unit 3 is a camera, and the camera is connected to the control module through a Cameralink interface, and the Cameralink interface is used to convey the photographed image;

[0068] Specifically, Cameralink is a protocol specifically for digital image transmission. In the protocol, 4-bit data enable control signals are defined, namely the frame synchronization signal (FVAL), the line synchronization signal (LVAL), the data valid signal (DVAL), and the idle standby signal. The signals are all high-valid; when performing image acquisition, by judging whether the three signals FVAL, LVAL, and DVAL are valid, real-time image data can be acquired; the camera can start working in the external trigger mode, and in the external trigger mode, the camera frame rate is controlled by sending an external trigger signal (SYN);

[0069] Specifically, as Figure 2 shown, the photographing unit 3 and the control module 4 are also connected bidirectionally through a serial port, which is used for the control module 4 to configure the camera gain, exposure time and other parameters. At the same time, after the photographing unit 3 receives the parameter information, it feeds back to the control module 4;

[0070] Specifically, as Figure 2 shown, the control module 4 is an FPGA chip, and the FPGA chip contains various memories, which are divided into FIFO (First In First Out) memories, ROM (Read Only Memory) memories, and RAM (Random Access Memory) memories; each of the AOTF units is correspondingly provided with the ROM memory, and the ROM memory is used to store the radio frequency driving frequency and send the radio frequency driving frequency to the target AOTF unit 2 according to the target wavelength; there is one RAM memory, and the RAM memory is used to store the target wavelength and target frame rate sent by the host computer 5; each of the photographing units 3 is correspondingly provided with the FIFO memory, and at the same time, there is one FIFO total memory corresponding to the host computer 5. The FIFO memory stores the photographed images corresponding to the photographing unit 3 and sequentially stores them in the FIFO total memory. The host computer 5 sequentially receives and displays the photographed images;

[0071] In some embodiments, the target wavelength received by the control module 4 is single fixed wavelength information. The target wavelength and target frame rate are sent to the control module 4 through the host computer 5. The control module 4 receives the target wavelength and target frame rate and stores them in the RAM memory. The control module 4 determines the AOTF unit 2 corresponding to the target wavelength. The control module 4 converts the target wavelength into a radio frequency driving frequency. The target AOTF unit 2 reads the radio frequency driving frequency, and the target AOTF unit 2 adjusts the corresponding set wavelength to the target wavelength, and the incident light corresponding to the target wavelength passes through; the control module 4 adjusts the set frame rate corresponding to the photographing unit 3 connected to the target AOTF unit 2 to the target frame rate. At this time, the photographing unit 3 starts to collect the image corresponding to the target wavelength. The photographing unit analyzes the image data through the Cameralink protocol. After the analysis is completed, the image is stored in the corresponding FIFO memory through the Cameralink interface and sequentially transported to the FIFO total memory; for the convenience of subsequent image analysis and display, the control module 4 makes information marks on the image data cached in the FIFO total memory, including camera type, image wavelength, image frame number, and image frame rate, etc. After the marking is completed, the image is transmitted to the host computer 5 for display through the USB3.0 interface.

[0072] In certain embodiments, the control module 4 is further configured to: receive the first signal sent by the target AOTF unit 2, and when it is determined that the first signal is at a low level, send the radio frequency driving frequency to the target AOTF unit 2;

[0073] The target AOTF unit 2 is further configured to: when receiving the radio frequency driving frequency, pull up the first signal;

[0074] The control module 4 is further configured to: when receiving the image captured by the target imaging unit 3, send a second signal to the target AOTF unit 2;

[0075] The target AOTF unit 2 is further configured to: when receiving the second signal, pull down the first signal.

[0076] Specifically, the first signal is Figure 2 the AOTF_in signal shown; the second signal is Figure 2 the AOTF_out signal shown;

[0077] In some embodiments, the target wavelengths received by the control module 4 include multiple wavelength information. The target wavelength and the target frame rate are sent to the control module 4 through the host computer 5. The control module 4 receives the target wavelength and the target frame rate and stores them in the RAM memory. The control module 4 sequentially reads a wavelength information, the control module 4 determines the AOTF unit 2 corresponding to the read target wavelength, and the control module 4 converts the target wavelength into a radio frequency driving frequency;

[0078] The control module 4 receives the first signal sent by the target AOTF unit 2. When it determines that the first signal is at a low level, the control module 4 sends the radio frequency driving frequency to the target AOTF unit 2 through the serial port; at this time, to prevent mistransmission, when the target AOTF unit 2 receives the radio frequency driving frequency, it pulls up the first signal, and the control module 4 stops sending the radio frequency driving frequency to the target AOTF unit 2; the incident light corresponding to the set wavelength of the target AOTF unit 2 is adjusted to the target wavelength and passes through; the control module adjusts the set frame rate corresponding to the imaging unit 3 connected to the target AOTF unit 2 to the target frame rate. At this time, the imaging unit 3 starts to collect the image corresponding to the target wavelength. The imaging unit analyzes the image data through the Cameralink protocol. After the analysis is completed, the image is stored in the corresponding FIFO memory through the Cameralink interface. At this time, the control module 4 sends a second signal to the target AOTF unit 2. When the target AOTF unit 2 receives the second signal, it pulls down the first signal, and the target AOTF unit 2 can be configured for the next time;

[0079] After that, the control module 4 sequentially reads the next wavelength information, and repeats the above steps for image acquisition until all the images corresponding to the wavelength information stored in the RAM memory are acquired; after the acquisition is completed, the images are sent to the FIFO general memory in the acquisition order; for the convenience of subsequent image analysis and display, the control module 4 marks the image data cached in the FIFO general memory, including the camera type, image wavelength, image frame number, and image frame rate, etc. After the marking is completed, the image is transmitted to the host computer 5 for display through the USB3.0 interface;

[0080] In some embodiments, the target wavelength sent by the host computer is single wavelength plus fixed step information. After completing one image acquisition according to the above steps, the host computer 5 calculates the next wavelength according to the initial wavelength and step, and sends it to the control module 4, and repeats the above steps to complete the cyclic acquisition of the image.

[0081] In some embodiments, an optical system 6 is provided at the input end of the plurality of AOTF units 2, and a measured target 7 is provided in front of the optical system 6. The optical system 6 is used to compress the light incident angle of the measured target 7 within a set field of view angle range.

[0082] Specifically, the optical system 6 is used to compress the light incident angle of the measured target 7 within a set field of view angle range, and can capture the target more accurately.

[0083] Embodiment 2

[0084] The present application provides a multi-spectral image acquisition and processing method based on AOTF, which adopts the above-mentioned multi-spectral image acquisition system based on AOTF. The multi-spectral image acquisition and processing method based on AOTF includes the following steps:

[0085] Receive the target wavelength and target frame rate;

[0086] Adjust the corresponding set wavelength of the target AOTF unit 2 to the target wavelength, where the target AOTF unit 2 is: the AOTF unit 2 whose adjustment range among all the AOTF units 2 includes the target wavelength;

[0087] Adjust the corresponding set frame rate of the target shooting unit 3 to the target frame rate, where the target shooting unit 3 is: the shooting unit 3 connected to the target AOTF unit 2;

[0088] Receive the image captured by the target shooting unit 3.

[0089] In some embodiments, the following steps are further included:

[0090] Convert the target wavelength into the corresponding radio frequency driving frequency;

[0091] Send the radio frequency drive frequency to the target AOTF unit 2, and adjust the corresponding set wavelength of the target AOTF unit 2 to the target wavelength.

[0092] In some embodiments, the following steps are further included:

[0093] Receive the first signal sent by the target AOTF unit 2. When it is determined that the first signal is at a low level, send the radio frequency drive frequency to the target AOTF unit 2; when the target AOTF unit 2 receives the radio frequency drive frequency, raise the first signal; when the image captured by the target imaging unit 3 is received, send a second signal to the target AOTF unit 2; when the target AOTF unit 2 receives the second signal, lower the first signal.

[0094] The above description is only the preferred embodiments of the present application and the description of the applied technical principles. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solutions formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. A multi-spectral image acquisition system based on AOTF, characterized in that, Comprising: A plurality of acquisition modules (1), each of the acquisition modules (1) including an AOTF unit (2) and an imaging unit (3) connected to the output end of the AOTF unit (2); the AOTF unit (2) is configured to control the passage of incident light having a set wavelength, the set wavelength being adjustable within the adjustment range of the AOTF unit (2); different AOTF units (2) have different adjustment ranges; the imaging unit (3) is configured to capture images at a set frame rate; by using a plurality of AOTF units (2) having different adjustment ranges, the wavelength range of the collected spectrum is broadened; An optical system (6) is provided at the input ends of the plurality of AOTF units (2), a target to be measured (7) is provided in front of the optical system (6), and the optical system (6) is configured to compress the light incident angle of the target to be measured (7) within a set field of view range to ensure that the incident light satisfies the working field of view angle of the AOTF unit (2), thereby improving the accuracy and stability of spectrum acquisition; A control module (4), an image input end of the control module (4) is connected to the output ends of the plurality of imaging units (3), and a first output end of the control module is connected to the control ends of the plurality of AOTF units (2) and the control ends of the plurality of imaging units (3); The control module (4) is configured to: Receive a target wavelength and a target frame rate; Adjust the set wavelength corresponding to the target AOTF unit (2) to the target wavelength, the target AOTF unit (2) being: the AOTF unit (2) whose adjustment range among all the AOTF units (2) includes the target wavelength; Adjust the set frame rate corresponding to the target imaging unit (3) to the target frame rate, the target imaging unit (3) being: the imaging unit (3) connected to the target AOTF unit (2); Receive the images captured by the target imaging unit (3).

2. The multispectral image acquisition system based on AOTF according to claim 1, wherein An image output end of the control module (4) is connected to a host computer (5), and an output end of the host computer (5) is connected to an information input end of the control module (4); The host computer (5) is configured to: Send a target wavelength and a target frame rate; Receive and display the images sent by the control module (4).

3. The multispectral image acquisition system based on AOTF according to claim 1, characterized in that, The AOTF unit (2) is configured to receive different radio frequency drive frequencies, and then adjust the set wavelength within the adjustment range of the AOTF unit (2); The control module (4) is further configured to: Convert the target wavelength into a corresponding radio frequency drive frequency; Send the radio frequency drive frequency to the target AOTF unit (2), and adjust the set wavelength corresponding to the target AOTF unit (2) to the target wavelength.

4. A multi-spectral image acquisition system based on AOTF according to claim 3, wherein The control module (4) is further configured to: receive a first signal sent by the target AOTF unit (2), and when it is determined that the first signal is at a low level, send the radio frequency drive frequency to the target AOTF unit (2); The target AOTF unit (2) is further configured to: when receiving the radio frequency driving frequency, pull up the first signal; The control module (4) is further configured to: when receiving the image captured by the target imaging unit (3), send a second signal to the target AOTF unit (2); The target AOTF unit (2) is further configured to: when receiving the second signal, pull down the first signal.

5. A multi-spectral image acquisition and processing method based on AOTF, characterized in that, Using the multi-spectral image acquisition system based on AOTF described in claim 1, the multi-spectral image acquisition and processing method based on AOTF includes the following steps: Receiving a target wavelength and a target frame rate; Adjusting the corresponding set wavelength of the target AOTF unit (2) to the target wavelength, where the target AOTF unit (2) is: the AOTF unit (2) whose adjustment range among all the AOTF units (2) includes the target wavelength; Adjusting the corresponding set frame rate of the target imaging unit (3) to the target frame rate, where the target imaging unit (3) is: the imaging unit (3) connected to the target AOTF unit (2); Receiving the image captured by the target imaging unit (3).

6. The multi-spectral image acquisition and processing method based on AOTF according to claim 5, characterized in that It further includes the following steps: Converting the target wavelength into a corresponding radio frequency driving frequency; Sending the radio frequency driving frequency to the target AOTF unit (2) and adjusting the corresponding set wavelength of the target AOTF unit (2) to the target wavelength.

7. A method for multi-spectral image acquisition and processing based on AOTF according to claim 6, characterized in that It further includes the following steps: Receiving the first signal sent by the target AOTF unit (2), when determining that the first signal is at a low level, sending the radio frequency driving frequency to the target AOTF unit (2); when the target AOTF unit (2) receives the radio frequency driving frequency, pulling up the first signal; When receiving the image captured by the target imaging unit (3), sending a second signal to the target AOTF unit (2); when the target AOTF unit (2) receives the second signal, pulling down the first signal.

Images