Negative film irradiation profile bright imaging method and system

Abstract

The invention discloses a negative film irradiation profile bright imaging method and system, and belongs to the technical field of optics, and the method comprises the following steps: S1, building a negative film irradiation profile bright imaging system; s2, collecting CCD image data, and carrying out initial processing on the CCD image data; s3, the projection is adjusted, and the preliminary conjecture of the shape features of the soil body is completed; s4, comparing the generated predicted projection effect with the actual projection effect through algorithm iteration, continuously optimizing, and outputting a final high-resolution image; and S5, the computer processes the high-resolution image according to the final contour information to finally obtain a clear resolution plate image. According to the invention, the problems of low imaging resolution, complex equipment, high cost and damage to samples or limitation of application scenes in the prior art are solved. The method can improve the imaging resolution, reduces the equipment complexity and cost, can avoid the damage to the sample, and is suitable for application scenes with high requirements for the integrity of the sample.

Description

Technical Field

[0001] The invention relates to the field of optical technology, and in particular to a negative film irradiation outline imaging method and system. Background Art

[0002] In the field of optical imaging, with the continuous advancement of science and technology, imaging technology has achieved remarkable development. Traditional optical imaging systems are mainly based on simple lens combinations, which realize the imaging of objects through the refraction and focusing of light, such as common cameras, microscopes, etc. In recent years, with the development of laser technology, light modulation technology and image sensor technology, the resolution and sensitivity of optical imaging have been improved to a certain extent. For example, high-resolution CCD and CMOS image sensors are widely used to obtain more image details; some advanced laser light sources are also used in specific imaging scenarios, providing more stable and coherent lighting.

[0003] In terms of image clarity improvement, existing technologies are mainly studied from two directions: on the one hand, at the hardware level, the manufacturing process and performance of optical components are continuously improved, such as using better optical materials to reduce aberrations and designing more complex optical system structures to optimize the optical path; on the other hand, at the software algorithm level, image post-processing algorithms such as sharpening and denoising are used to improve the visual effect of the image. For example, common image denoising algorithms such as mean filtering and median filtering can reduce the noise in the image to a certain extent, but at the same time, some image details will be lost.

[0004] Although there are many methods to improve imaging resolution, such as confocal microscopy technology, which improves resolution by point-by-point scanning and spatial filtering, the equipment is complex, the scanning speed is slow, and the cost is high, which is not suitable for large-scale, fast imaging needs. There is also super-resolution fluorescence imaging technology, which can break through the traditional optical diffraction limit, but requires fluorescent labeling of samples, which may cause certain damage to the samples, and the operation process is cumbersome, limiting its application in some fields with high requirements for sample integrity. In short, the existing technology has the following defects:

[0005] 1) Low imaging resolution: Traditional imaging methods are unable to meet the requirements for high-resolution imaging of tiny objects and objects with complex structures, and are unable to clearly present the subtle features of objects, resulting in limited applications in industrial inspection, biomedical imaging, and cultural relics protection. For example, when inspecting tiny solder joints on electronic chips, low-resolution imaging cannot accurately determine whether the solder joints have problems such as cold solder joints or short circuits.

[0006] 2) The equipment is complex and costly: Some methods to improve resolution, such as the confocal microscope and super-resolution fluorescence imaging equipment mentioned above, have complex structures and require high-precision optical components, complex optical path systems, and sophisticated control systems. This makes the equipment cost high and difficult to maintain and operate. Only a few scientific research institutions and large enterprises can afford it, which is not conducive to the widespread application and promotion of the technology.

[0007] 3) Scenarios that damage or limit application of samples: Super-resolution fluorescence imaging technology that requires fluorescent labeling of samples cannot be applied in areas such as cultural relics protection and long-term observation of living cells, because these scenarios require that the original state of the samples is not destroyed, while traditional imaging methods cannot meet the needs of high-resolution imaging in these special scenarios. Summary of the invention

[0008] The purpose of the present invention is to provide a negative film illumination outline imaging method and system, which utilizes the characteristics of a spatial light modulator (SLM) that can flexibly modulate the light field, projects negative film light to illuminate the object, and then combines iterative optimization of the algorithm to gradually improve the imaging resolution and recognition accuracy of the object, thereby solving the problems raised in the above-mentioned background technology.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] The negative film irradiation outline imaging method comprises the following steps:

[0011] S1: Build negative film irradiation outline imaging system;

[0012] S2: Collect CCD image data and perform initial processing on the collected CCD image data;

[0013] S3: Adjust the projection and make a preliminary guess about the soil shape characteristics;

[0014] S4: Through algorithm iteration, the generated predicted projection effect is compared with the actual projection effect, and the optimization is continuously performed to output the final high-resolution image;

[0015] S5: The computer processes the final high-resolution image according to the extracted contour information, adjusts the image contrast and brightness parameters through gamma correction, suppresses background noise through Gaussian filtering, and convolves the image with a Gaussian kernel function to smooth the noise, and finally obtains a clear resolution plate image to improve the overall imaging clarity.

[0016] Preferably, in S1, a negative film irradiation outline imaging system is constructed, and the following operations are performed:

[0017] The 638nm laser, spatial light modulator SLM, resolution board, polarization beam splitter prism, 1 / 4 wave plate and charge coupled device CCD are sequentially built according to a specific optical path and the working state is adjusted;

[0018] Among them, the 638nm laser is used as the light source to provide stable coherent light for the entire optical imaging process; the spatial light modulator SLM is used to modulate the light beam and change the phase and amplitude characteristics of the light; the resolution plate is used as the target object for imaging; the polarization beam splitter prism is used to split or combine the light path; the 1 / 4 wave plate is used to convert the modulated reflected laser beam into P light transmission, and the charge-coupled device CCD is used to collect the final optical image and convert it into an electrical signal for transmission to the computer.

[0019] Preferably, in S2, CCD image data is collected and the following operations are performed:

[0020] A laser with a wavelength of 638nm is used as the light source. The 638nm laser emits a laser beam with a wavelength of 638nm. The laser beam is evenly irradiated onto the spatial light modulator SLM. The computer controls the spatial light modulator SLM to place known negative image information to modulate the laser beam so that the laser beam carries the negative information. After the laser beam modulated by the spatial light modulator SLM becomes an object negative, it is irradiated onto the resolution board. After the resolution board transmits, scatters and diffracts the light, it is finally imaged onto the charge-coupled device CCD. At this time, a preliminary information image reflecting the approximate outline of the object is obtained through the charge-coupled device CCD to determine the CCD image data.

[0021] Preferably, in S2, the laser beam is uniformly irradiated onto the spatial light modulator SLM, including:

[0022] After the laser beam is emitted, it enters the beam expansion and collimation system. After the beam expansion and collimation, the parallel laser beam is modulated into horizontal polarized light by a polarizer, and then incident on the polarization beam splitter prism. The polarization beam splitter prism is based on optical polarization coating and structural design, and can split the horizontal polarized light into S light and P light. The S light is reflected to the spatial light modulator SLM, and the spatial light modulator SLM is pre-loaded and plays the negative film information that is the same as the resolution board pattern. Through pixel-level analysis of the image, the spatial light modulator SLM can modulate the incident laser beam in real time according to the grayscale or color information of the image, so that the reflected light carries the optical information related to the resolution board;

[0023] The laser beam modulated and reflected by the spatial light modulator SLM is converted into P light transmission through a 1 / 4 wave plate and directly irradiated onto the resolution board. The resolution board, as a standard element for testing the resolution of the optical system, has patterns with different line widths and spacings. The patterns with different line widths and spacings are used to test the optical system's ability to resolve information of different spatial frequencies. When the laser beam carrying the modulated information irradiates the resolution board, the pattern on the resolution board will diffract the laser beam to generate a diffracted light beam carrying the resolution information. Finally, the diffracted light beam is then received by the charge coupled device CCD.

[0024] Preferably, in S2, the collected CCD image data is initially processed by performing the following operations:

[0025] The CCD image data is de-noised based on Gaussian filtering, wherein the value of each pixel in the CCD image data is obtained by weighted averaging the value of itself and other pixels in the neighborhood, thereby eliminating Gaussian noise in the CCD image data;

[0026] The contrast of CCD image data is enhanced based on histogram equalization, wherein the CCD image data is segmented into a plurality of grayscale segments, for each grayscale segment, the mean and standard deviation of all pixel values ​​in the segment are calculated, and according to the principle of histogram equalization, the range of each pixel value is adjusted based on an interpolation method to make it conform to a preset threshold range, and the adjusted pixel value is mapped back to the original grayscale domain to obtain a de-equalized image, thereby enhancing the contrast of the CCD image data;

[0027] Based on principal component analysis, feature extraction is performed on CCD image data to extract resolution-related features from the CCD image data, including edges, contours, colors, and textures.

[0028] Preferably, in S3, the projection is adjusted and a preliminary guess of the soil shape characteristics is completed, and the following operations are performed:

[0029] According to the initial imaging results on the charge-coupled device (CCD), for the thicker or misaligned parts of the contour results, the negative information that needs to be placed on the spatial light modulator (SLM) is adjusted and modified accordingly. After changing the negative pattern on the spatial light modulator (SLM) and the details corresponding to the contour, light is projected again to illuminate the object and image it on the charge-coupled device (CCD). By repeating S2 many times and manually adjusting the difference between the negative and the obtained contour information, the final imaging is basically close to a completely black image, and the shape and features of the object are preliminarily obtained through the adjusted negative.

[0030] Preferably, in S4, the generated predicted projection effect is compared with the actual projection effect through algorithm iteration, and the optimization is continued to output the final high-resolution image, and the following operations are performed:

[0031] S41: transmitting the CCD image data on the charge coupled device CCD to the computer, analyzing and processing the CCD image data using a pre-written algorithm, calculating the projection pattern to be loaded by the next spatial light modulator SLM according to the imaging result after the previous projection adjustment, and continuously iterating and optimizing the process;

[0032] S42: algorithm iteration initialization, first inputting the initial guess image, the number of iterations N and the error threshold ε, obtaining the initial CCD image data from the charge coupled device CCD, and performing denoising, contrast enhancement and feature extraction preprocessing on the CCD image data;

[0033] S43: the iterative process is cycled N times, the current error is calculated, the current guessed image is compared with the actual image collected on the charge coupled device CCD, the error between the two is calculated based on the mean square error calculation method, and according to the error information, a pre-written algorithm is used to calculate the projection pattern that the spatial light modulator SLM should load next time, and the Gerchberg-Saxton algorithm is used to iterate between the spatial domain and the frequency domain using Fourier transform and inverse transform to update the guessed image, calculate a new projection pattern, and load the calculated projection pattern onto the spatial light modulator SLM;

[0034] S44: The charge coupled device (CCD) collects the object image modulated by the new projection pattern and outputs a final high-resolution image.

[0035] According to another aspect of the present invention, a negative film illumination outline imaging system is provided, which is used to implement the negative film illumination outline imaging method as described above, comprising:

[0036] A user interface module is used to provide a graphical user interface for users to interact with the system, wherein CCD image data collected by the charge coupled device CCD, patterns loaded by the spatial light modulator SLM and processing results are displayed, allowing users to set parameters and start or stop the program;

[0037] The SLM control module is used to generate and load the projection pattern to the spatial light modulator SLM according to the output of the algorithm module, control the refresh frequency, resolution, phase and amplitude modulation mode of the spatial light modulator SLM, load the corresponding grayscale image to the spatial light modulator SLM, and update the pattern displayed by the spatial light modulator SLM in real time;

[0038] The CCD image acquisition module is used to control the charge coupled device (CCD) to acquire CCD image data, set the exposure time, gain and resolution parameters of the charge coupled device (CCD), display them in the user interface, and save the original image data for subsequent processing;

[0039] An image processing module is used to preprocess the collected CCD image data and extract image features;

[0040] The algorithm module is used to calculate the spatial light modulator SLM pattern of the next iteration according to the CCD image data and the current spatial light modulator SLM pattern, and finally calculate the error and update the spatial light modulator SLM pattern.

[0041] Preferably, the user interface module includes:

[0042] A human-computer interaction unit, used for user interaction with the computer;

[0043] An interface display unit, used to display CCD image data, loaded patterns and processing results;

[0044] The parameter setting unit is used to set computer parameters and modify the parameters.

[0045] Preferably, the image processing module includes:

[0046] An image denoising unit is used to denoise the collected CCD image data and eliminate Gaussian noise in the CCD image data;

[0047] An image enhancement unit, used for contrast enhancement of the denoised CCD image data;

[0048] The feature extraction unit is used to extract features from the contrast-enhanced CCD image data.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] 1. The present invention calculates the projection pattern that the spatial light modulator SLM should load next time based on the imaging result after the previous projection adjustment through algorithm iteration. In the process of continuous iteration, the accuracy of guessing the object is gradually improved, thereby improving the imaging resolution. As the number of iterations increases, the algorithm can more accurately match the actual characteristics of the object, making the imaging clearer and able to distinguish the finer structures of the object. Combined with the fast calculation of the algorithm, the entire imaging and recognition process can be completed in a shorter time, thereby improving efficiency.

[0051] 2. The optical system constructed by the present invention is relatively simple, and is mainly composed of basic optical elements such as a spatial light modulator SLM, an illumination light source, an actual object, and a charge-coupled device CCD. Object imaging and recognition are achieved through reasonable optical path arrangement and the coordination of spatial light modulator SLM negative film projection and algorithm iteration. Compared with some methods that require complex multi-beam interference systems or expensive special lenses to improve resolution, the present invention does not need to introduce too much complex equipment, greatly reduces the complexity and cost of the equipment, and can achieve higher-resolution imaging detection based on relatively simple equipment, thereby reducing the cost of the enterprise.

[0052] 3. The charge coupled device (CCD) of the present invention has the characteristics of high sensitivity, high resolution, low noise, etc. It can convert the received optical image information into electrical signals completely and accurately, and transmit it to the computer through a high-speed data transmission interface. The computer's built-in image processing algorithm covers multiple functions such as image enhancement, denoising, and edge detection, and can quickly extract key information related to resolution from the original image data. The entire data acquisition and processing process is efficient and accurate. Compared with the incomplete data acquisition or slow processing speed in some existing technologies, the system can obtain high-quality measurement data in a short time and conduct effective analysis, greatly improving the efficiency of optical system performance evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a structural diagram of the negative film irradiation outline imaging system of the present invention;

[0054] Figure 2 It is a flow chart of the negative film irradiation outline imaging system of the present invention;

[0055] Figure 3 It is a module diagram of the negative film irradiation outline imaging system of the present invention;

[0056] Figure 4 It is a schematic diagram of simulation results of the negative film irradiation outline imaging system of the present invention;

[0057] Figure 5 It is a schematic diagram of the experimental results of the negative film irradiation outline imaging system of the present invention;

[0058] Figure 6 It is a schematic diagram of the SLM playback picture of the negative film irradiation outline imaging system of the present invention. DETAILED DESCRIPTION

[0059] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0060] In order to solve the existing problems of low imaging resolution, complex equipment and high cost, damage to samples or limited application scenarios, please refer to Figure 1-Figure 6 , this embodiment provides the following technical solutions:

[0061] The negative film irradiation outline imaging method comprises the following steps:

[0062] S1. Build negative film irradiation outline imaging system:

[0063] The 638nm laser, spatial light modulator SLM, resolution board, polarization beam splitter prism, 1 / 4 wave plate and charge coupled device CCD are sequentially built according to a specific optical path and adjusted to a suitable working state;

[0064] Among them, the 638nm laser is used as the light source to provide stable coherent light for the entire optical imaging process; the spatial light modulator SLM is used to modulate the light beam and change the phase and amplitude characteristics of the light; the resolution plate is used as the imaging target object; the polarization beam splitter prism is used to split or combine the light path; the 1 / 4 wave plate is used to convert the modulated reflected laser beam into P light transmission, and the charge coupled device CCD is used to collect the final optical image and convert it into an electrical signal for transmission to the computer;

[0065] S2, collecting CCD image data, and performing initial processing on the collected CCD image data:

[0066] A laser with a wavelength of 638nm is used as a light source. The 638nm laser emits a laser beam with a wavelength of 638nm. The laser beam is uniformly irradiated onto the spatial light modulator SLM. The spatial light modulator SLM is controlled by a computer to place known negative image information to modulate the laser beam so that the laser beam carries the negative information for subsequent interaction with the resolution board. After the laser beam modulated by the spatial light modulator SLM becomes an object negative, it is irradiated onto the resolution board. After the resolution board transmits, scatters and diffracts the light, it is finally imaged onto the charge coupled device CCD. At this time, an information image reflecting the general outline of the object is initially obtained through the charge coupled device CCD to determine the CCD image data;

[0067] The CCD image data is de-noised based on Gaussian filtering, wherein the value of each pixel in the CCD image data is obtained by weighted averaging the value of itself and other pixels in the neighborhood, thereby eliminating Gaussian noise in the CCD image data;

[0068] The contrast of CCD image data is enhanced based on histogram equalization, wherein the CCD image data is segmented into a plurality of grayscale segments, for each grayscale segment, the mean and standard deviation of all pixel values ​​in the segment are calculated, and according to the principle of histogram equalization, the range of each pixel value is adjusted based on an interpolation method to make it conform to a preset threshold range, and the adjusted pixel value is mapped back to the original grayscale domain to obtain a de-equalized image, thereby enhancing the contrast of the CCD image data;

[0069] Based on principal component analysis, feature extraction is performed on CCD image data to extract resolution-related features from CCD image data, including edges, contours, colors, and textures;

[0070] S3. Adjust the projection and make a preliminary guess about the soil shape characteristics:

[0071] According to the initial imaging result on the charge coupled device CCD, for the part with thick or misaligned contour on the contour result, the negative information to be placed on the spatial light modulator SLM is adjusted and modified accordingly. After changing the details corresponding to the contour of the negative pattern on the spatial light modulator SLM, light is projected again to illuminate the object and image it on the charge coupled device CCD. By repeating S2 many times and manually adjusting the difference between the negative and the obtained contour information, the final image is basically close to a completely black image, and the shape and characteristics of the object are preliminarily obtained through the adjusted negative.

[0072] S4. Through algorithm iteration, the generated predicted projection effect is compared with the actual projection effect, and the optimization is continued to output the final high-resolution image:

[0073] S41: The CCD image data on the charge coupled device CCD is transmitted to the computer, and the CCD image data is analyzed and processed using a pre-written algorithm. According to the imaging result after the previous projection adjustment, the projection pattern to be loaded by the spatial light modulator SLM next time is calculated, and the process is continuously iterated and optimized to gradually improve the accuracy of the guessing of the object and the resolution of the imaging;

[0074] S42: algorithm iteration initialization, first inputting the initial guess image, the number of iterations N and the error threshold ε, obtaining the initial CCD image data from the charge coupled device CCD, and performing denoising, contrast enhancement and feature extraction preprocessing on the CCD image data;

[0075] S43: the iterative process is cycled N times, the current error is calculated, the current guessed image is compared with the actual image collected on the charge coupled device CCD, the error between the two is calculated based on the mean square error calculation method, and according to the error information, a pre-written algorithm is used to calculate the projection pattern that the spatial light modulator SLM should load next time, and the Gerchberg-Saxton algorithm is used to iterate between the spatial domain and the frequency domain using Fourier transform and inverse transform to update the guessed image, calculate a new projection pattern, and load the calculated projection pattern onto the spatial light modulator SLM;

[0076] S44: the charge coupled device (CCD) collects the object image modulated by the new projection pattern and outputs a final high-resolution image;

[0077] S5: The computer processes the final high-resolution image according to the contour information finally extracted, and adjusts the contrast and brightness parameters of the image through gamma correction. The gamma correction can enhance the details of the dark area while maintaining the details of the highlight area. The background noise is suppressed through Gaussian filtering, and the image is convolved with a Gaussian kernel function to smooth the noise, thereby improving the clarity of the resolution plate imaging, and finally obtaining a clear resolution plate image, completing the entire process of improving the imaging clarity.

[0078] Therefore, by building a specific optical system, the spatial light modulator SLM is used to project light of a negative film that is imaged with the actual object, and the light is irradiated on the actual object and finally imaged on the charge-coupled device CCD through projection or reflection to obtain the outline of an object or a completely black image. Subsequently, the outline is extracted through an algorithm and the projection of the spatial light modulator SLM is continuously adjusted, and iteration is combined to gradually guess the object and improve the imaging resolution. The imaging resolution can be effectively improved, and the subtle structure and features of the object can be clearly presented, meeting the requirements for high-precision detection of product quality in industrial inspection, the research needs for microstructures in the biomedical field, and the digital recording and restoration of cultural relics details in cultural relics protection. The complexity and cost of equipment can be reduced, and the use of complex and expensive equipment can be avoided through relatively simple optical system construction and algorithm implementation, making the technology easier to promote and apply, and damage to samples can be avoided. It is suitable for application scenarios with high requirements for sample integrity.

[0079] In order to better demonstrate the principle of negative film illumination outline imaging, this embodiment now provides a negative film illumination outline imaging system, which is used to implement the negative film illumination outline imaging method as described above, including:

[0080] A user interface module is used to provide a graphical user interface for users to interact with the system, wherein CCD image data collected by the charge coupled device CCD, patterns loaded by the spatial light modulator SLM and processing results are displayed, allowing users to set parameters and start or stop the program;

[0081] The SLM control module is used to generate and load the projection pattern to the spatial light modulator SLM according to the output of the algorithm module, control the refresh frequency, resolution, phase and amplitude modulation mode of the spatial light modulator SLM, load the corresponding grayscale image to the spatial light modulator SLM, and update the pattern displayed by the spatial light modulator SLM in real time;

[0082] The CCD image acquisition module is used to control the charge coupled device (CCD) to acquire CCD image data, set the exposure time, gain and resolution parameters of the charge coupled device (CCD), display them in the user interface, and save the original image data for subsequent processing;

[0083] An image processing module is used to preprocess the collected CCD image data and extract image features;

[0084] The algorithm module is used to calculate the spatial light modulator SLM pattern of the next iteration according to the CCD image data and the current spatial light modulator SLM pattern, and finally calculate the error and update the spatial light modulator SLM pattern.

[0085] Specifically, according to the initial imaging results, the projection pattern of the spatial light modulator SLM is adjusted by the program, and irradiation and imaging are performed again to start the iteration process of the algorithm. During the iteration process, the changes in the imaging are closely monitored. When the preset number of iterations is reached or the imaging resolution meets the requirements, the iteration is stopped and the final imaging data is analyzed and processed by the program.

[0086] In this embodiment, the user interface module includes:

[0087] A human-computer interaction unit, used for user interaction with the computer;

[0088] An interface display unit, used to display CCD image data, loaded patterns and processing results;

[0089] The parameter setting unit is used to set computer parameters and modify the parameters.

[0090] In this embodiment, the image processing module includes:

[0091] An image denoising unit is used to denoise the collected CCD image data and eliminate Gaussian noise in the CCD image data;

[0092] An image enhancement unit, used for contrast enhancement of the denoised CCD image data;

[0093] The feature extraction unit is used to extract features from the contrast-enhanced CCD image data.

[0094] Specifically, the system uses a laser with a wavelength of 638nm as the light source at the starting end. The laser can output a high-stability, low-noise continuous laser beam. A high-resolution spatial light modulator SLM is selected with a resolution of 1980*1080 pixels. After the laser beam is emitted, it immediately enters the beam expansion and collimation system. The beam expansion and collimation system is composed of a series of high-precision optical lenses. Through precise lens combination and design, it can achieve effective beam expansion of the laser beam, increase the beam diameter, and eliminate the divergence angle of the beam, ensuring that the laser beam is emitted in the form of parallel light, providing high-quality beam conditions for the stable operation of subsequent optical components; the parallel laser beam after beam expansion and collimation is modulated into horizontally polarized light by a polarizer, and then incident on a polarization beam splitter prism. The polarization beam splitter prism can split light into S light and P light based on its special optical polarization coating and structural design, where the S light is reflected to the space The light modulator SLM, the spatial light modulator SLM is pre-loaded with and plays the negative film information identical to the pattern of the resolution board. Through pixel-level analysis of the image, the spatial light modulator SLM can modulate the incident laser beam in real time according to the grayscale or color information of the image, so that the reflected light carries the optical information related to the resolution board; the laser beam modulated and reflected by the spatial light modulator SLM is converted into P light transmission through a 1 / 4 wave plate and directly irradiated onto the resolution board. The resolution board, as a standard element for the resolution test of the optical system, has a series of patterns with different line widths and spacings, which are used to test the optical system's ability to resolve information of different spatial frequencies; when the laser beam carrying the modulated information irradiates the resolution board, the pattern on the resolution board diffracts the laser beam to generate a diffracted light beam carrying the resolution information, which is then received by the charge-coupled device CCD.

[0095] When the negative film irradiation outline imaging method is used for imaging experiments, it has the following characteristics:

[0096] 1) Imaging resolution can be improved: Traditional imaging methods are difficult to obtain clear contours and sufficiently high resolution when dealing with complex surface structures or tiny objects. The present invention effectively improves the imaging resolution by combining spatial light modulator SLM negative film projection with algorithm iteration. The algorithm iterates and calculates the projection pattern that the next spatial light modulator SLM should load based on the imaging result after the previous projection adjustment. In the process of continuous iteration, the accuracy of guessing the object is gradually improved, thereby improving the imaging resolution. As the number of iterations increases, the algorithm can more accurately match the actual characteristics of the object, making the imaging clearer and able to distinguish more subtle structures of the object. For example, in the field of biomedical imaging, for the imaging of tiny objects such as cells, traditional methods may not be able to clearly display the internal structure of the cell, while the method of the present invention can improve the resolution through iteration and clearly present structures such as organelles inside the cell.

[0097] (2) Reduce equipment complexity and cost: Some current methods for improving imaging resolution generally have the problem of complex equipment and high cost. The optical system constructed by the present invention is relatively simple, mainly composed of basic optical elements such as spatial light modulator SLM, illumination light source, actual object and charge coupled device CCD. Object imaging and recognition are achieved through reasonable optical path arrangement and coordination of spatial light modulator SLM negative film projection and algorithm iteration; compared with some methods that require complex multi-beam interference systems or expensive special lenses to improve resolution, the present invention does not need to introduce too many complex equipment, greatly reducing equipment complexity and cost. For example, in industrial inspection, for the detection of surface defects of some products, if traditional high-resolution imaging equipment is used, it may cost a lot of money to purchase equipment and the equipment maintenance is complicated. The method of the present invention can achieve high-resolution imaging detection based on relatively simple equipment, reducing the cost of the enterprise.

[0098] (3) Improve efficiency: Traditional imaging methods have low imaging and recognition efficiency when facing complex objects; in the algorithm iteration process of the present invention, each iteration is optimized based on the results of the previous iteration, which can quickly approach the real characteristics of the object. In addition, the spatial light modulator SLM has the characteristic of fast response. For example, the selected spatial light modulator SLM with a fast response time of less than 1 millisecond can quickly adjust the projection pattern. Combined with the fast calculation of the algorithm, the entire imaging and recognition process can be completed in a shorter time. In the field of cultural relics protection, a large number of cultural relics need to be imaged and recognized quickly to record information. The method of the present invention can quickly obtain clear images of cultural relics and identify them, thereby improving the efficiency of cultural relic information collection.

[0099] (4) Efficient data acquisition and processing: The charge-coupled device (CCD) has the characteristics of high sensitivity, high resolution, and low noise. It can convert the received optical image information into electrical signals completely and accurately, and transmit it to the computer through a high-speed data transmission interface. The computer's built-in image processing algorithm covers a variety of functions such as image enhancement, denoising, and edge detection, and can quickly extract key information related to resolution from the original image data. The entire data acquisition and processing process is efficient and accurate. Compared with some existing technologies where data acquisition is incomplete or processing is slow, the system can obtain high-quality measurement data in a short time and perform effective analysis, greatly improving the efficiency of optical system performance evaluation. This advantage stems from the excellent photoelectric conversion performance of the charge-coupled device (CCD) itself and the application of a high-speed data transmission interface. At the same time, the advanced image processing algorithms in the computer also provide a guarantee for efficient data processing.

[0100] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0101] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A negative film irradiation outline imaging method, characterized in that: The steps include: S1: Build negative film irradiation outline imaging system; S2: Collect CCD image data and perform initial processing on the collected CCD image data; S3: Adjust the projection and make a preliminary guess about the soil shape characteristics; S4: Through algorithm iteration, the generated predicted projection effect is compared with the actual projection effect, and the optimization is continuously performed to output the final high-resolution image; S5: The computer processes the final high-resolution image according to the extracted contour information, adjusts the image contrast and brightness parameters through gamma correction, suppresses background noise through Gaussian filtering, and convolves the image with a Gaussian kernel function to smooth the noise, and finally obtains a clear resolution plate image to improve the overall imaging clarity.

2. The negative film irradiation outline imaging method according to claim 1, characterized in that: In S1, a negative film irradiation and contour imaging system is constructed, and the following operations are performed: The 638nm laser, spatial light modulator SLM, resolution board, polarization beam splitter prism, 1 / 4 wave plate and charge coupled device CCD are sequentially built according to a specific optical path and the working state is adjusted; Among them, the 638nm laser is used as the light source to provide stable coherent light for the entire optical imaging process; the spatial light modulator SLM is used to modulate the light beam and change the phase and amplitude characteristics of the light; the resolution plate is used as the imaging target object; the polarization beam splitter prism is used to split or combine the light path; the 1 / 4 wave plate is used to convert the modulated reflected laser beam into P light transmission, and the charge-coupled device CCD is used to collect the final optical image and convert it into an electrical signal for transmission to the computer.

3. The negative film irradiation outline imaging method according to claim 2, characterized in that: In S2, CCD image data is collected and the following operations are performed: A laser with a wavelength of 638nm is used as the light source. The 638nm laser emits a laser beam with a wavelength of 638nm. The laser beam is evenly irradiated onto the spatial light modulator SLM. The computer controls the spatial light modulator SLM to place known negative image information to modulate the laser beam so that the laser beam carries the negative information. After the laser beam modulated by the spatial light modulator SLM becomes an object negative, it is irradiated onto the resolution board. After the resolution board transmits, scatters and diffracts the light, it is finally imaged onto the charge-coupled device CCD. At this time, a preliminary information image reflecting the approximate outline of the object is obtained through the charge-coupled device CCD to determine the CCD image data.

4. The negative film irradiation outline imaging method according to claim 3, characterized in that: In S2, the laser beam is uniformly irradiated onto the spatial light modulator SLM, including: After the laser beam is emitted, it enters the beam expansion and collimation system. After the beam expansion and collimation, the parallel laser beam is modulated into horizontal polarized light by a polarizer, and then incident on the polarization beam splitter prism. The polarization beam splitter prism is based on optical polarization coating and structural design, and can split the horizontal polarized light into S light and P light. The S light is reflected to the spatial light modulator SLM, and the spatial light modulator SLM is pre-loaded and plays the negative film information that is the same as the resolution board pattern. Through pixel-level analysis of the image, the spatial light modulator SLM can modulate the incident laser beam in real time according to the grayscale or color information of the image, so that the reflected light carries the optical information related to the resolution board; The laser beam modulated and reflected by the spatial light modulator SLM is converted into P light transmission through a 1 / 4 wave plate and directly irradiated onto the resolution board. The resolution board, as a standard element for testing the resolution of the optical system, has patterns with different line widths and spacings. The patterns with different line widths and spacings are used to test the optical system's ability to resolve information of different spatial frequencies. When the laser beam carrying the modulated information irradiates the resolution board, the pattern on the resolution board will diffract the laser beam to generate a diffracted light beam carrying the resolution information. Finally, the diffracted light beam is then received by the charge coupled device CCD.

5. The negative film irradiation outline imaging method according to claim 4, characterized in that: In S2, the collected CCD image data is initially processed by performing the following operations: The CCD image data is subjected to denoising based on Gaussian filtering, wherein the value of each pixel in the CCD image data is obtained by weighted averaging, thereby eliminating Gaussian noise in the CCD image data; The contrast of CCD image data is enhanced based on histogram equalization, wherein the CCD image data is segmented into a plurality of grayscale segments, for each grayscale segment, the mean and standard deviation of all pixel values ​​in the segment are calculated, and according to the principle of histogram equalization, the range of each pixel value is adjusted based on an interpolation method to conform to a preset threshold range, and the adjusted pixel value is mapped back to the original grayscale domain to obtain a de-equalized image, thereby enhancing the contrast of the CCD image data; Based on principal component analysis, feature extraction is performed on CCD image data to extract resolution-related features from the CCD image data, including edges, contours, colors, and textures.

6. The negative film irradiation outline imaging method according to claim 5, characterized in that: In S3, the projection is adjusted and a preliminary guess of the soil shape characteristics is completed by performing the following operations: According to the initial imaging results on the charge-coupled device (CCD), for the thicker or misaligned parts of the contour results, the negative information that needs to be placed on the spatial light modulator (SLM) is adjusted and modified accordingly. After changing the negative pattern on the spatial light modulator (SLM) and the details corresponding to the contour, light is projected again to illuminate the object and image it on the charge-coupled device (CCD). By repeating S2 many times and manually adjusting the difference between the negative and the obtained contour information, the final imaging is basically close to a completely black image, and the shape and features of the object are preliminarily obtained through the adjusted negative.

7. The negative film irradiation outline imaging method according to claim 6, characterized in that: In S4, the generated predicted projection effect is compared with the actual projection effect through algorithm iteration, and the optimization is continued to output the final high-resolution image, and the following operations are performed: S41: transmitting the CCD image data on the charge coupled device CCD to the computer, analyzing and processing the CCD image data using a pre-written algorithm, calculating the projection pattern to be loaded by the next spatial light modulator SLM according to the imaging result after the previous projection adjustment, and continuously iterating and optimizing the process; S42: algorithm iteration initialization, first inputting the initial guess image, the number of iterations N and the error threshold ε, obtaining the initial CCD image data from the charge coupled device CCD, and performing denoising, contrast enhancement and feature extraction preprocessing on the CCD image data; S43: the iterative process is cycled N times, the current error is calculated, the current guessed image is compared with the actual image collected on the charge coupled device CCD, the error between the two is calculated based on the mean square error calculation method, and according to the error information, a pre-written algorithm is used to calculate the projection pattern that the spatial light modulator SLM should load next time, and the Gerchberg-Saxton algorithm is used to iterate between the spatial domain and the frequency domain using Fourier transform and inverse transform to update the guessed image, calculate a new projection pattern, and load the calculated projection pattern onto the spatial light modulator SLM; S44: The charge coupled device (CCD) collects the object image modulated by the new projection pattern and outputs a final high-resolution image.

8. A negative film illumination outline imaging system, used to implement the negative film illumination outline imaging method according to claim 7, characterized in that: include: A user interface module is used to provide a graphical user interface for users to interact with the system, wherein CCD image data collected by the charge coupled device CCD, patterns loaded by the spatial light modulator SLM and processing results are displayed, allowing users to set parameters and start or stop the program; The SLM control module is used to generate and load the projection pattern to the spatial light modulator SLM according to the output of the algorithm module, control the refresh frequency, resolution, phase and amplitude modulation mode of the spatial light modulator SLM, load the corresponding grayscale image to the spatial light modulator SLM, and update the pattern displayed by the spatial light modulator SLM in real time; The CCD image acquisition module is used to control the charge coupled device (CCD) to acquire CCD image data, set the exposure time, gain and resolution parameters of the charge coupled device (CCD), display them in the user interface, and save the original image data for subsequent processing; An image processing module is used to preprocess the collected CCD image data and extract image features; The algorithm module is used to calculate the spatial light modulator SLM pattern of the next iteration according to the CCD image data and the current spatial light modulator SLM pattern, and finally calculate the error and update the spatial light modulator SLM pattern.

9. The negative film irradiation outline imaging method according to claim 8, characterized in that: The user interface module comprises: A human-computer interaction unit, used for user interaction with the computer; An interface display unit, used to display CCD image data, loaded patterns and processing results; The parameter setting unit is used to set computer parameters and modify the parameters.

10. The negative film irradiation outline imaging method according to claim 9, characterized in that: The image processing module comprises: An image denoising unit is used to denoise the collected CCD image data and eliminate Gaussian noise in the CCD image data; An image enhancement unit, used for contrast enhancement of the denoised CCD image data; The feature extraction unit is used to extract features from the contrast-enhanced CCD image data.

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