Latest Research & Patent Insights on UAV Thermal Imaging

Optical system for far-infrared cameras that provides good imaging quality, compact size, thermal stability, and ease of manufacture. The system uses a combination of sulfur lenses and a metalens. The sulfur lenses correct low-order aberrations, while the metalens corrects high-order aberrations and off-axis aberrations. The metalens can be stacked layers of unit cells. An aperture slot can be placed near the metalens to control light intake.

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A joint imaging system for efficient and rapid collection of visible light and thermal infrared images using an unmanned aerial vehicle (UAV) platform. The system enables effective spatial registration and pixel-level fusion of the images to obtain thermal infrared images with texture details. The UAV carries two cameras, one visible light and one thermal infrared, with offset angles. This allows simultaneous imaging of the same scene from different angles. The images are then fused by scaling and aligning them based on offset vectors. This provides high-quality thermal images with texture details for applications like 3D modeling.

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Thermal imager for satellites, aircraft, and UAVs that achieves high-resolution thermal imaging without active cooling. The imager employs an array of thermopile-based IC chips, each with a dedicated wavelength filter, to capture thermal radiation in multiple spectral bands. By synchronizing the sampling of adjacent rows of IC chips, the imager enables stereoscopic imaging and spectral subtraction to infer atmospheric properties and surface temperature. The design eliminates the need for active cooling, enabling compact and power-efficient thermal imaging systems for small platforms.

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A joint imaging system for unmanned aerial vehicles (UAVs) that integrates visible light and thermal infrared cameras to enable simultaneous collection of high-resolution images from multiple angles. The system employs a novel image enhancement fusion method that synchronizes and registers the thermal and visible light images in real-time, enabling effective pixel-level fusion and accurate feature point recognition. This enables efficient and rapid collection of high-quality images for 3D modeling and other applications.

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Unmanned aerial vehicle-based thermal anomaly detection system for buildings, enabling efficient and comprehensive thermal imaging of structural defects. The system employs a UAV equipped with thermal cameras and visible light sensors to capture thermal and visible images of building structures. The UAV performs systematic flight patterns around the structure, defining thermal boundaries and identifying temperature anomalies through pixel analysis. The system calculates heat loss rates before and after anomaly detection, providing a comprehensive understanding of building thermal performance.

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Infrared thermal imaging temperature measurement method and device for unmanned aerial vehicles (UAVs) that addresses the issue of temperature instability in thermal imaging detectors. The method involves acquiring data from the thermal imaging assembly, including operating temperature and original gray value images, and determining temperature values for different sub-regions using calibration data and the acquired data. The device includes an acquisition module for acquiring the data and a determination module for determining the temperature values. The method also includes calibration steps to generate calibration information for the thermal imaging assembly.

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A lens assembly for thermal infrared imaging comprising a substrate, a functional layer with sub-wavelength microstructures, and an imaging layer with non-periodic microstructures. The functional layer provides anti-reflection and hydrophobic properties while the imaging layer focuses infrared light onto a thermal sensor. The lens assembly enables compact, weather-resistant thermal imaging devices with improved environmental adaptability.

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Non-contact temperature measurement device and method that corrects temperature measurement errors caused by object emissivity and camera-object distance using multiple infrared cameras with different wavelength bands. The device estimates pixel correspondence between images captured by cameras with the same wavelength band, estimates camera-object distance based on the correspondence, and corrects temperature measurements using images captured by cameras with different wavelength bands.

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A drone-based inspection system that can fly, hover, and navigate around structures to perform the inspection in an efficient/fast manner can considerably reduce inspection time. Active thermography is a well-known non-destructive testing method for inspection. However, using it on a drone is challenging due to the drone needing to carry an appropriate heat source, batteries or tethering system to power the heat source and to provide adequate flight time. This complicates the inspection process and can restrict the amount of thermal energy that can be applied to the inspected structure. Another challenge with drone-based active infrared thermography (DBAIT) is that, unlike traditional active thermography inspection in which, the source is either stationary or moving in a precisely controlled manner, the drone and the heat source are subjected to undesired dynamic motion. This paper presents the results of experiments performed to compare potential heat sources that can be retrofitted onboard a drone to conduct active thermographic inspection.

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Athermalized lens systems and methods for infrared imaging that maintain focus across temperature changes. The systems employ a combination of thermal compensation techniques, including active focus adjustment and passive mechanical athermalization, to counteract thermal expansion and refractive index changes in the lens elements. The lens elements are specifically designed with materials having tailored coefficients of thermal expansion to achieve optimal thermal compensation.

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Thermal infrared imaging mechanism and electronic equipment that enhances the field of view of thermal infrared cameras by using a diffractive optical element array to collect and concentrate thermal infrared light onto a photosensitive unit. The diffractive optical element array is positioned in a vacuum chamber adjacent to the photosensitive unit, and the thermal infrared light is diffracted and focused onto the photosensitive unit, increasing the amount of light collected and enabling a wider field of view.

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Thermal imaging system that achieves higher resolution than its micro mirror array by measuring multiple frames with sub-pixel offsets during each frame generation cycle, leveraging high-speed optical image sensors to capture detailed thermal radiation distributions.

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Infrared sensor with improved detection accuracy, comprising a substrate, a sensor element with a thermoelectric conversion section and a light receiving section separated by a hollow support, and an amplifier with a switchable input terminal. The sensor element's hollow support structure enhances thermal insulation and reduces thermal time constant, while the switchable input terminal enables mode switching between noise measurement and infrared detection modes. The sensor's design minimizes signal leakage and crosstalk between pixels, enabling high-speed and high-sensitivity infrared detection.

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To measure low-temperature thermal fields, we have developed a single-element cooled thermal imaging camera for a spectral range of 8{\div}14 {\mu}m with an internal shutter for radiometric calibration. To improve the accuracy of measuring the temperature of cold objects, we used a shutter with a combined emissivity as an internal reference source of radiation at the input of the device optical unit. With this aim a small mirror was fixed in the center on its surface covered black, thereby ensuring an efficient reflection of radiation in a wide spectral range of wavelengths. When processing the signal for each pixel of the thermal image, the differential value of the detector response to the shutter blackened and mirror areas was used as a reference. A relative measurement error of 3 percent was obtained for the studied objects with a temperature of -150 {\deg}C. The device was successfully used for remote study of thermal field dynamics during freeze-thawing of biological tissues in vivo.

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Due to the limitations and costs of thermal sensors, unmanned aerial vehicle (UAV) platforms often equip with high-resolution (HR) visible imaging and low-resolution (LR) thermal imaging cameras for all-day monitoring capability. Existing works generate the high-resolution thermal UAV images by either super-resolution (SR) from high-resolution visible and low-resolution thermal images or modality conversion (MC) from high-resolution visible images. However, the modality gap between visible and thermal sources might degrade the generation quality. We observe that the MC task is beneficial in addressing the cross-modal gap in the SR task, while the SR task can provide the condition of thermal information to boost the MC task. Moreover, these two tasks have the same output and can thus be carried out simultaneously without any additional annotation. Based on this observation, we propose a collaborative enhancement network (CENet), which performs thermal UAV image SR and visible image MC in a joint manner, for high-resolution thermal UAV image generation. In particular, we design a mutua... Read More

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With the advancement of drone technology, object detection from the perspective of drones has found extensive applications in various fields, including surveillance, search operations, and reconnaissance tasks. Currently, most drones in the market are equipped with visible light imagers, while some high-end drones are equipped with infrared imaging detectors capable of performing infrared object detection tasks. Infrared imaging utilizes a passive imaging mode, enabling it to detect thermal radiation emitted by objects. As a result, it offers the distinct advantage of continuous operation without being restricted by daylight conditions. In comparison to visible imaging, infrared imaging uses longer wavelengths and possesses a certain level of penetration capability through clouds and smoke. Consequently, infrared object detection represents a significant research area within the field of object detection. However, detecting infrared objects, especially small ones, remains challenging due to the complexity of background information, lower resolution compared to visible images, and the... Read More

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A two-point correction method for infrared images that improves image quality by mitigating temperature-induced degradation. The method uses a blackbody with a temperature matching the lens temperature and a second blackbody with a higher temperature to generate correction parameters. These parameters are obtained through a fitting process and are used to accurately calculate corrected gray values, eliminating the "pot lid" effect caused by non-uniformity.

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Building heat loss quantification using image analysis to improve building thermal performance and energy usage optimization. The system captures images of buildings using drones, detects objects like roofs and windows, estimates their temperatures, and calculates the heat transfer coefficient (U-value) based on the temperatures. This data-driven approach leverages deep learning, clustering, and thermal imaging to quantify heat loss for building efficiency improvements. The technique reduces uncertainties related to weather conditions, image capture, and object detection to provide accurate building analytics.

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A nanoscale bolometer for infrared imaging that operates near the thermodynamic limit. The device features a thin suspended membrane structure with subwavelength antenna for radiation absorption, and a thermometer for temperature measurement. By nanostructuring the membrane and support beams, the device achieves a radiative thermal conductance that approaches the fundamental limit, enabling a 10-30× increase in specific detectivity compared to commercial microbolometers.

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An uncooled infrared camera that reduces noise in captured images by using a black body section to cover a portion of the detector, extracting noise from the covered area, and removing it from the entire image. The camera can further improve temperature estimation by rotating a polarizer and estimating a temperature model based on the detected temperatures and rotation angles.

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