An imaging dynamic range expansion method and system using light scattering

Abstract

The application provides an imaging dynamic range expansion method and system using light scattering, which introduces a spatial light modulator and a scattering modulator in the imaging process, dynamically adjusts the light field distribution entering the subsequent imaging system by adjusting the control mode of the internal device of the spatial light modulator, generates a mask to remove the interference of strong background light, retains the information light of the target, and realizes the rapid accumulation of micrometer-level target light information and the suppression of background light. The introduction of the scattering modulator can disperse the large dynamic range scene light in the imaging system, diffuse the strong light energy, avoid the overexposure of the detector, make the information originally exceeding the response range of the detector enter the detectable range, thereby increase the dynamic range of the imaging detection, and realize the high-efficiency and high-performance large dynamic range imaging.

Description

Technical Field

[0001] This invention belongs to the field of optical imaging technology, specifically relating to a method and system for extending the dynamic range of imaging using light scattering. Background Technology

[0002] For over a decade, the application of optoelectronic imaging systems has been constrained by the dynamic range of optoelectronic sensors. When using cameras, optical sights, and other optoelectronic imaging devices to image scenes with bright objects or light sources within the field of view, the high brightness can cause intensity saturation of the optoelectronic sensor, resulting in overexposure and a severe deterioration in image quality. Overexposure in bright areas not only leads to the loss of image details but can also trigger a series of chain reactions, such as measurement errors, difficulties in target recognition, and even affecting the stability and reliability of the entire system. Therefore, large dynamic range scene imaging has become a research hotspot. In the field of traffic vision, large dynamic range imaging technology can effectively cope with complex road conditions where strong light and shadows coexist, improving the recognition accuracy and safety of autonomous driving systems. In the field of automated mechanical manufacturing, the presence of glare can prevent detection equipment from accurately capturing targets or images, thus affecting its detection accuracy and efficiency. Furthermore, prolonged exposure to glare can cause fatigue in the visual system of detection equipment, further reducing its performance. The resulting impacts include decreased work efficiency, reduced product quality, and increased safety hazards. In intelligent manufacturing and security monitoring, high dynamic range (HDR) imaging technology ensures the clarity and stability of real-time monitoring images in the face of constantly changing lighting conditions, safeguarding production and safety. In the aerospace field, the intense glare from searchlights and other powerful light sources makes it difficult for technicians to see instruments. In low visibility conditions, excessively high light intensity can even interfere with technicians' vision, causing glare and affecting their judgment of the surrounding environment. Therefore, HDR imaging technology is crucial for detecting and analyzing complex space environments and ground targets. In computational photography, this technology helps photographers create more artistically expressive and visually impactful works in high-contrast environments. Currently, HDR imaging technologies include intensity attenuation imaging, HDR imaging, and event camera imaging.

[0003] Intensity attenuation imaging technology utilizes optical materials such as attenuators to effectively adjust the intensity of light entering the imaging system. This technology can uniformly reduce the intensity of light across all wavelengths, thereby avoiding image saturation and loss of detail in scenes with a large dynamic range.

[0004] High Dynamic Range (HDR) imaging technology captures and synthesizes a series of images taken at different exposure levels to simultaneously preserve details in both low-light and high-light areas within a single image, thus achieving a wider dynamic range than a single-exposure image. This technology is highly effective in scenes requiring simultaneous capture of details in both dark and bright areas, such as shooting in high-contrast environments, significantly enhancing image detail and visual impact. Its core advantage lies in its ability to precisely synthesize and process multiple images through optimized software algorithms, providing a more realistic visual experience.

[0005] Event camera imaging technology only outputs data when it detects a brightness change exceeding a preset threshold. This working mechanism gives event cameras advantages such as extremely low latency, high dynamic range, and low power consumption. These characteristics make event cameras particularly outstanding in applications with high real-time requirements and drastic lighting changes, making them suitable for dynamic scene monitoring and rapid-response imaging tasks.

[0006] However, the above technologies have certain drawbacks:

[0007] Intensity attenuation imaging technology uses optical materials such as attenuators to reduce the intensity of light entering the imaging system. While suppressing background light interference, this can also reduce the contrast of the imaged target, making it difficult to effectively detect target details. Although this technology can solve the imaging problem in high-brightness environments to some extent, its impact on overall image quality cannot be ignored, especially in scenes where contrast is crucial, where this drawback is particularly noticeable.

[0008] HDR technology requires the detector to acquire multiple frames of data. If the detector jitters or the target moves during this process, motion blur or ghosting will occur in the synthesized data. Furthermore, high dynamic range imaging technology only better fuses existing information and cannot reveal information not present in the synthesized image. This limitation prevents its application in dynamic scenes or scenes requiring high-precision static details. Although algorithmic optimization can mitigate these problems to some extent, its fundamental limitations remain.

[0009] Event camera imaging technology utilizes biomimetic sensors (brain-like) with microsecond response times to record asynchronous streams of brightness changes per pixel, called "events." It generates an event by detecting brightness changes in each pixel. However, event cameras can only output moving pixels, making them unsuitable for traditional vision methods. Furthermore, event cameras only output "positive" and "negative" signals, lacking the intensity information found in traditional optical imaging, significantly hindering the identification and confirmation of critical target areas. For example, in tasks such as object recognition and feature extraction, traditional cameras rely on rich grayscale or color information to determine the shape, texture, and edges of objects. Event cameras, by only outputting event signals of brightness changes, make these tasks even more complex and challenging.

[0010] While these technologies have made some progress in improving the adaptability of optoelectronic imaging systems to scenes with large dynamic ranges, further optimization and improvement are still needed in terms of image quality, real-time performance, system cost, environmental adaptability, and application scope. Therefore, researching an imaging technology that extends dynamic range has significant application value and promising prospects. Summary of the Invention

[0011] To address the aforementioned problems in the prior art, this invention provides a method and system for extending the dynamic range of imaging using light scattering. The technical problem to be solved by this invention is achieved through the following technical solution:

[0012] In a first aspect, the present invention provides an imaging dynamic range extension method utilizing light scattering, applied to an imaging dynamic range extension system utilizing light scattering, the system comprising a spatial light modulator, a spatial filter, a scattering modulator, and a detector, wherein the imaging dynamic range extension method utilizing light scattering includes:

[0013] S100, adjust the spatial light modulator so that all incident light fields entering the spatial light modulator are reflected into the spatial filter; the incident light field is the light reflected by all objects in the large dynamic range scene.

[0014] S200 uses a spatial filter to filter the incident light field fed back from the spatial light modulator to obtain the filtered light field.

[0015] S300: The filtered light field is diffused using a scattering modulator to obtain a first speckle pattern, and then the target contour information in the first speckle pattern is detected by a detector to obtain a target mask.

[0016] S400, based on target mask control of spatial light modulator, so that a portion of the light field containing target information in the incident light entering the spatial light modulator is reflected to the spatial filter;

[0017] S500 uses a spatial filter to filter a portion of the optical field fed back from the spatial light modulator to obtain a filtered portion of the optical field.

[0018] S600 uses a scattering modulator to diffuse a portion of the filtered light field to obtain a second speckle pattern, and then uses a detector to detect the target information in the second speckle pattern to obtain target detail information.

[0019] S700, the target mask and the target detail information are combined to form an original target image.

[0020] In a second aspect, the present invention provides an imaging dynamic range extension system utilizing light scattering, wherein the imaging dynamic range extension system utilizing light scattering performs imaging using the imaging dynamic range extension method utilizing light scattering described in the first aspect.

[0021] Beneficial effects:

[0022] 1. The imaging dynamic range extension method proposed in this invention utilizes light scattering. This method does not introduce complex optical components and has a simple process.

[0023] 2. This invention introduces a scattering modulator to diffuse strong light energy, and based on the scattering computational imaging theory, it can not only restore and reconstruct the target under a large dynamic range, improve imaging quality and increase the dynamic range of detection, but also avoid damage to the detector target surface.

[0024] 3. The spatial light modulator introduced in this invention can be used to select targets in real time in scenes with a large dynamic range, which can improve the real-time performance and accuracy of imaging.

[0025] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the application of the imaging dynamic range extension method utilizing light scattering provided by the present invention.

[0027] Figure 2 This is a flowchart illustrating an imaging dynamic range extension method utilizing light scattering provided by the present invention.

[0028] Figure 3 This is a schematic diagram of the process of the imaging dynamic range extension method using light scattering provided by the present invention. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0030] This invention provides a method for extending the dynamic range of an imaging system using light scattering, applicable to such systems. (Refer to...) Figure 1 As shown, the system includes a spatial light modulator, a spatial filter, a scattering modulator, and a detector. The scattering modulator diffuses intense light, allowing information that would otherwise be outside the detector's response range to enter the detectable range. Any device capable of diffused light in a large dynamic range scene can replace the scattering modulator. The spatial light modulator gates targets in a large dynamic range scene; any device capable of target gatening can replace the spatial light modulator.

[0031] exist Figure 1 In this system, 1 represents a scene with a strong light source containing faint target information; 2 is a spatial light modulator, whose main function is to control the scene with a large dynamic range; 3 is a spatial filter, whose main function is to filter the light field after it has been modulated by the spatial light modulator; 4 is an optical system, which can be added appropriately according to the actual imaging conditions; 5 is a scattering modulator, which can diffuse the light field of the scene with a large dynamic range, thereby avoiding overexposure of the detector and preventing damage to the detector target surface; and 6 is a detector, used to collect the diffused light field.

[0032] Combination Figure 2 and Figure 3 The present invention provides a method for extending the dynamic range of imaging using light scattering, comprising:

[0033] S100, adjust the spatial light modulator so that all incident light fields entering the spatial light modulator are reflected into the spatial filter; the incident light field is the light reflected by all objects in the large dynamic range scene.

[0034] This invention utilizes a high-precision spatial light modulator to select the target imaging region. By precisely adjusting the angle and position of the spatial light modulator, it can dynamically adjust the distribution of light entering the imaging system, effectively suppressing background light interference and achieving rapid accumulation of target light information at the micrometer level and suppression of background light.

[0035] S200 uses a spatial filter to filter the incident light field fed back from the spatial light modulator to obtain the filtered light field.

[0036] S300: The filtered light field is diffused using a scattering modulator to obtain a first speckle pattern, and then the target contour information in the first speckle pattern is detected by a detector to obtain a target mask.

[0037] The target outline generates a corresponding target mask on the scattering modulator, thereby avoiding interference from strong background light information in a large dynamic range scene, resulting in the attenuation of strong background light and the enhancement of the target area.

[0038] The introduction of a scatter modulator diffuses the large dynamic range scene, allowing information that was originally outside the detector's response range to enter the detectable range, thereby increasing the detector's dynamic range and achieving large dynamic range imaging.

[0039] In an optional embodiment of the present invention, S300 includes:

[0040] S310, the energy of the filtered light field is diffused using the scattering modulator to obtain the first speckle pattern;

[0041] S320, using the detector to detect the target contour information in the first speckle image, and obtaining the pixel value of each pixel in the first speckle image;

[0042] S330, based on the pixel value of each pixel in the first speckle image, the target mask is recovered using a target reconstruction algorithm. The target reconstruction algorithm includes a speckle recovery algorithm, which uses a deconvolution algorithm to recover the image. The deconvolution algorithm includes Wiener filtering, regularized deconvolution, and blind deconvolution algorithms, among others.

[0043] Specifically, when an incoherent beam of light strikes a target, the object light passing through the target is incident on a scattering modulator. The light exiting the scattering modulator is scattered, thus enabling speckle to be detected on the camera. Based on the optical memory effect of speckle, when the object is small, light emitted from two points on the object forms two speckle patterns after passing through the frosted glass. These two speckle patterns are translationally invariant and highly correlated. Approximately, these two speckle patterns are almost identical, only undergoing slight displacement. Therefore, the speckle emitted from the entire object can be considered as a simple superposition of the speckle emitted from each point on the object. The speckle emitted from each point on the object can be viewed as the point spread function of this imaging system. ).

[0044] Therefore, the speckle detected by the detector It is approximately equal to the intensity distribution of the object. and the system Convolution:

[0045]

[0046] The asterisk (*) indicates a convolution operation.

[0047] If the system The intensity distribution image of the object has already been obtained in advance, and based on this, a deconvolution algorithm can be used to extract the intensity distribution image of the object. From speckled If the speckle recovery algorithm recovers the speckle pattern, the recovery process can be expressed by the following formula:

[0048]

[0049] In the formula, It is the recovered target mask. This indicates the deconvolution operation. This is the first speckle pattern. It is a point spread function.

[0050] S400, based on target mask control of spatial light modulator, so that a portion of the incident light field containing target information in the spatial light modulator is reflected to the spatial filter;

[0051] S500 uses a spatial filter to filter a portion of the optical field fed back from the spatial light modulator to obtain a filtered portion of the optical field.

[0052] S600 uses a scattering modulator to diffuse a portion of the filtered light field to obtain a second speckle pattern, and then uses a detector to detect the target information in the second speckle pattern to obtain target detail information.

[0053] In an optional embodiment of the present invention, S600 includes:

[0054] S610, the second speckle pattern is obtained by using the scattering modulator to diffuse a portion of the filtered light field;

[0055] S620, the detector is used to detect the second speckle pattern to obtain the pixel value of each pixel in the second speckle pattern;

[0056] S630, based on the pixel value of each pixel in the second speckle map, the target detail information is recovered through the target reconstruction algorithm.

[0057] The S600 and S300 use the same principle to recover the original target image using a target reconstruction algorithm. This target reconstruction algorithm includes a speckle recovery algorithm, which uses a deconvolution algorithm to recover the image. The deconvolution algorithm includes Wiener filtering, regularized deconvolution, and blind deconvolution algorithms, etc. The recovery process of the speckle recovery algorithm can be expressed by the following formula:

[0058]

[0059] In the formula, It is the recovered target details. This indicates the deconvolution operation. This is the second speckle pattern. It is a point spread function.

[0060] It is worth noting that the target mask is recovered through S300, which reflects the surrounding contour of the target. In S600, the target contour information is combined with the target reconstruction algorithm to reconstruct the details within the target contour.

[0061] S700, the target mask and the target detail information are combined to form an original target image.

[0062] This step involves a simple combination of the target mask and the target detail information to obtain the original target image.

[0063] In an optional embodiment of the present invention, the imaging dynamic range extension method utilizing light scattering further includes:

[0064] refer to Figure 2 An optical system is set between the scattering modulator and the spatial filter according to the actual imaging conditions. The optical system is configured to direct the filtered light field into the scattering modulator along the optical path.

[0065] The actual imaging conditions include: the distance between the scattering modulator and the spatial filter, the width of the filtered light field output by the spatial filter, and whether further filtering is required.

[0066] It is worth noting that if the distance between the scattering modulator and the spatial filter is too far, exceeding a predetermined distance, less of the filtered light field will enter the scattering modulator, thus requiring the addition of an optical system. Similarly, if the width of the filtered light field output by the spatial filter is wide, again less of the filtered light field will enter the scattering modulator, requiring the addition of an optical system. The purpose is to ensure that the entire filtered light field is incident on the scattering modulator along the optical path. If further filtering is required, an optical system can be added to perform a second filtering of the filtered light field.

[0067] This invention utilizes a light scattering imaging dynamic range extension system to select target contours and recover target information in scenes with a large dynamic range. Its core principle is to generate a mask at the corresponding position of the spatial light modulator based on the recovered target contour in the large dynamic range scene, thereby avoiding interference from strong background light and leaving behind the information light containing the target. The introduction of the scattering modulator mainly disperses the energy of the strong light field, preventing overexposure of the detector.

[0068] In a second aspect, the present invention provides an imaging dynamic range extension system utilizing light scattering, which performs imaging using the imaging dynamic range extension method utilizing light scattering described in the first aspect.

[0069] In one specific embodiment of the present invention, the imaging dynamic range extension system utilizing light scattering further includes:

[0070] An optical system is provided, which is positioned between the scattering modulator and the spatial filter according to the actual imaging conditions, and is used to direct the filtered light field entirely into the scattering modulator along the optical path.

[0071] The actual imaging conditions include: the distance between the scattering modulator and the spatial filter, the width of the filtered light field output by the spatial filter, and whether further filtering is required.

[0072] This invention proposes a method and system for extending the dynamic range of imaging using light scattering. By introducing a spatial light modulator and a scattering modulator during the imaging process, and precisely adjusting the angle and position of the spatial light modulator, the distribution of light entering the spatial filter can be dynamically adjusted to generate a mask, thereby avoiding interference from strong background light and retaining the information light containing the target. This effectively suppresses background light interference, achieving rapid accumulation of target light information at the micrometer level and suppression of background light. The introduction of the scattering modulator can diffuse the large dynamic range scene, disperse the energy of the strong light field, and prevent overexposure of the detector. This allows information that was originally outside the detector's response range to enter the detectable range, thereby increasing the detector's dynamic range and achieving large dynamic range imaging. Therefore, it can improve imaging efficiency and imaging effect.

[0073] It is worth noting that the terms "first" and "second" in this invention are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0074] Although this application has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, the disclosure, and the appended claims in carrying out the claimed application. In the claims, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude a plurality.

[0075] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A method for extending the dynamic range of imaging using light scattering, characterized in that, An imaging dynamic range extension method utilizing light scattering is applied to an imaging dynamic range extension system, which includes a spatial light modulator, a spatial filter, a scattering modulator, and a detector. S100, adjust the spatial light modulator so that all incident light fields entering the spatial light modulator are reflected into the spatial filter; the incident light field is the light reflected by all objects in the large dynamic range scene. S200 uses a spatial filter to filter the incident light field fed back from the spatial light modulator to obtain the filtered light field. S300: The filtered light field is diffused using a scattering modulator to obtain a first speckle pattern, and then the target contour information in the first speckle pattern is detected by a detector to obtain a target mask. S400, based on target mask control of spatial light modulator, so that a portion of the light field containing target information in the incident light entering the spatial light modulator is reflected to the spatial filter; S500 uses a spatial filter to filter a portion of the optical field fed back from the spatial light modulator to obtain a filtered portion of the optical field. S600 uses a scattering modulator to diffuse a portion of the filtered light field to obtain a second speckle pattern, and then uses a detector to detect the target information in the second speckle pattern to obtain target detail information. S700, the target mask and the target detail information are combined to form an original target image.

2. The imaging dynamic range extension method utilizing light scattering according to claim 1, characterized in that, The imaging dynamic range extension method utilizing light scattering further includes: An optical system is set between the scattering modulator and the spatial filter according to the actual imaging conditions. The optical system is configured to direct the filtered light field into the scattering modulator along the optical path.

3. The imaging dynamic range extension method utilizing light scattering according to claim 2, characterized in that, The actual imaging conditions include: the distance between the scattering modulator and the spatial filter, the width of the filtered light field output by the spatial filter, and whether further filtering is required.

4. The imaging dynamic range extension method utilizing light scattering according to claim 1, characterized in that, The S300 includes: S310, the energy of the filtered light field is diffused using the scattering modulator to obtain the first speckle pattern; S320, using the detector to detect the target contour information in the first speckle image, and obtaining the pixel value of each pixel in the first speckle image; S330, the target mask is recovered based on the pixel value of each pixel in the first speckle map and through a target reconstruction algorithm.

5. The imaging dynamic range extension method utilizing light scattering according to claim 1, characterized in that, The S600 includes: S610, the second speckle pattern is obtained by using the scattering modulator to diffuse a portion of the filtered light field; S620, the detector is used to detect the second speckle pattern to obtain the pixel value of each pixel in the second speckle pattern; S630, based on the pixel value of each pixel in the second speckle map, the target detail information is recovered through the target reconstruction algorithm.

6. The imaging dynamic range extension method utilizing light scattering according to claim 4 or 5, characterized in that, The target reconstruction algorithm includes a speckle restoration algorithm, which uses a deconvolution algorithm to restore the image. The restoration process of the speckle restoration algorithm is expressed by the following formula: In the formula, It is the recovered target mask or target detail information. This indicates the deconvolution operation. Is it the first speckle pattern or the second speckle pattern? It is a point spread function.

7. The imaging dynamic range extension method utilizing light scattering according to claim 6, characterized in that, The deconvolution algorithms include Wiener filtering, regularized deconvolution, and blind deconvolution.

8. An imaging dynamic range extension system utilizing light scattering, characterized in that, The imaging dynamic range extension system utilizing light scattering performs imaging using the imaging dynamic range extension method utilizing light scattering as described in any one of claims 1 to 7.

9. The imaging dynamic range extension system utilizing light scattering according to claim 8, characterized in that, The imaging dynamic range extension system utilizing light scattering also includes: An optical system is provided, which is positioned between the scattering modulator and the spatial filter according to the actual imaging conditions, and is used to direct the filtered light field entirely into the scattering modulator along the optical path.

10. The imaging dynamic range extension system utilizing light scattering according to claim 9, characterized in that, The actual imaging conditions include: the distance between the scattering modulator and the spatial filter, the width of the filtered light field output by the spatial filter, and whether further filtering is required.

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