Recent Patents in Signal Processing (September 2017) – Infrared imaging

For our September 2017 issue, we cover recent patents granted in the area of infrared imaging and signal processing.

In patent no. 9,741,120, an infrared imaging detection and positioning method for an underground building in a planar land surface environment comprises: obtaining an original infrared image g0 formed after stratum modulation is performed on an underground building, and determining a local infrared image g of a general position of the underground building in the original infrared image g0; setting an iteration termination condition, and setting an initial value h0 of a Gaussian thermal diffusion function; using the local infrared image g as an initial target image f0, and performing iteration solution of a thermal expansion function h.sub.n and a target image fn by using a maximum likelihood estimation algorithm according to the initial value h0 of the Gaussian thermal diffusion function; and determining whether the iteration termination condition is met, if the iteration termination condition is met, using the target image f.sub.n obtained by means of iteration solution this time as a final target image f; and if the iteration termination condition is not met, continuing to perform iteration calculation. In the method, by performing demodulation processing on the infrared image formed after stratum modulation is performed on the underground building, the display of the infrared image of the original underground building is clearer, and the real structure of the underground building can be inverted.

In the invention no. 9,739,661 a method and apparatus for obtaining reference samples during the generation of a mid-infrared (MW) image without requiring that the sample being imaged be removed is disclosed. A tunable MIR laser generates a light beam that is focused onto a specimen on a specimen stage that moves the specimen in a first direction. An optical assembly includes a scanning assembly having a focusing lens and a mirror that moves in a second direction, different from the first direction, relative to the stage such that the focusing lens maintains a fixed distance between the focusing lens and the specimen stage. A light detector measures an intensity of light leaving the point on the specimen. A controller forms an image from the measured intensity. A reference stage is positioned such that the mirror moves over the reference stage in response to a command so that the controller can also make a reference measurement.

Various techniques are disclosed in patent no. 9,723,227 for performing non-uniformity correction (NUC) for infrared imaging devices. Intentionally blurred image frames may be obtained and processed to correct for FPN (e.g., random spatially uncorrelated FPN in one embodiment) associated with infrared sensors of the infrared imaging device. Intentionally blurred image frames may be used to distinguish between FPN associated with the infrared sensors and desired scene information. Advantageously, such techniques may be implemented without requiring the use of a shutter to perform flat field correction for the infrared imaging device.

Various techniques are provided in patent no. 9,716,844 for implementing an infrared imaging system, especially for low power and small form factor applications. In one example, a system includes a focal plane array (FPA). The FPA includes an array of infrared sensors adapted to image a scene. A low-dropout regulator (LDO) is integrated with the FPA and adapted to provide a regulated voltage in response to an external supply voltage. The FPA also includes a bias circuit adapted to provide a bias voltage to the infrared sensors in response to the regulated voltage. The FPA also includes a read out integrated circuit (ROIC) adapted to provide signals from the infrared sensors corresponding to captured image frames. Other implementations are also provided.

In patent no. 9,692,988 the subject matter disclosed involves systems, methods, apparatuses or devices related to infrared imaging or infrared imaging projection.

Infrared imaging devices are provided in patent no. 9,655,501 which are configured to implement side-scan infrared imaging for, e.g., medical applications. For example, an imaging device includes a ring-shaped detector element comprising a circular array of infrared detectors configured to detect thermal infrared radiation, and a focusing element configured to focus incident infrared radiation towards the circular array of infrared detectors. The imaging device can be an ingestible imaging device (e.g., swallowable camera) or the imaging device can be implemented as part of an endoscope device, for example.

Patent no. 9,642,532 presents an imaging system for acquisition of NIR and full-color images includes a light source providing visible light and NIR light to an area under observation, such as living tissue, a camera having one or more image sensors configured to separately detect blue reflectance light, green reflectance light, and combined red reflectance light/detected NIR light returned from the area under observation. A controller in signal communication with the light source and the camera is configured to control the light source to continuously illuminate area under observation with temporally continuous blue/green illumination light and with red illumination light and NIR excitation light. At least one of the red illumination light and NIR excitation light are switched on and off periodically in synchronism with the acquisition of red and NIR light images in the camera.

In patent no. 9,635,285 techniques using small form factor infrared imaging modules are disclosed. An imaging system may include visible spectrum imaging modules, infrared imaging modules, and other modules to interface with a user and/or a monitoring system. Visible spectrum imaging modules and infrared imaging modules may be positioned in proximity to a scene that will be monitored while visible spectrum-only images of the scene are either not available or less desirable than infrared images of the scene. Imaging modules may be configured to capture images of the scene at different times. Image analytics and processing may be used to generate combined images with infrared imaging features and increased detail and contrast. Triple fusion processing, including selectable aspects of non-uniformity correction processing, true color processing, and high contrast processing, may be performed on the captured images. Control signals based on the combined images may be presented to a user and/or a monitoring system.

If you have an interesting patent to share when we next feature patents related to infrared imaging, or if you are especially interested in a signal processing research field that you would want to be highlighted in this section, please send email to Csaba Benedek (benedek.csaba AT sztaki DOT mta DOT hu).

References

Number: 9,741,120
Title: Infrared imaging detection and positioning method for underground building in planar land surface environment
Inventors: Zhang; Tianxu (Hubei, CN), Hao; Longwei (Hubei, CN), Lu; Cen (Hubei, CN), Ma; Wenxuan (Hubei, CN), Wang; Yuehuan (Hubei, CN), Sang; Nong (Hubei, CN), Yang; Weidong (Hubei, CN)
Issued: August 22, 2017
Assignee: Huazhong University of Science and Technology (Wuhan, Hubei, CN)

Number: 9,739,661
Title: Infrared imaging system with automatic referencing
Inventors: Ghetler; Andrew (San Jose, CA), Kleczewski; Adam (San Francisco, CA), Tella; Richard P. (Sunnyvale, CA)
Issued: August 22, 2017
Assignee: Agilent Technologies, Inc. (Santa Clara, CA)

Number: 9,723,227
Title: Non-uniformity correction techniques for infrared imaging devices
Inventors: Hogasten; Nicholas (Santa Barbara, CA), Hoelter; Theodore R. (Goleta, CA), Strandemar; Katrin (Rimbo, SE)
Issued: August 1, 2017
Assignee: FLIR Systems, Inc. (Wilsonville, OR)

Number: 9,716,844
Title: Low power and small form factor infrared imaging
Inventors: Nussmeier; Mark (Goleta, CA), Kurth; Eric A. (Santa Barbara, CA), Hogasten; Nicholas (Santa Barbara, CA), Hoelter; Theodore R. (Goleta, CA), Strandemar; Katrin (Rimbo, SE), Boulanger; Pierre (Goleta, CA), Sharp; Barbara (Santa Barbara, CA)
Issued: July 25, 2017
Assignee: FLIR Systems, Inc. (Wilsonville, OR)

Number: 9,692,988
Title: Infrared imaging projection
Inventors: Reichow; Mark A. (Valencia, CA), Runco; Christopher Raynard (Burbank, CA), Brentnall; Thomas E. (Cypress, CA), LaDuke; Thomas Frasier (Orange, CA)
Issued: June 27, 2017
Assignee: Disney Enterprises, Inc. (Burbank, CA)

Number: 9,655,501
Title: Side-scan infrared imaging devices
Inventors: Kaufman; Peter N. (Fresh Meadows, NY)
Issued: May 23, 2017
Assignee: Digital Direct IR, Inc. (Fresh Meadows, NY)

Number: 9,642,532
Title: Imaging system for combined full-color reflectance and near-infrared imaging
Inventors: Fengler; John (North Vancouver, CA), Westwick; Paul R. (Vancouver, CA), Bailey; Aurther E. (North Vancouver, CA), Cottle; Paul (Vancouver, CA)
Issued: May 9, 2017
Assignee: Novadaq Technologies Inc. (Mississauga, CA)

Number: 9,635,285
Title: Infrared imaging enhancement with fusion
Inventors: Teich; Andrew C. (Goleta, CA), Hogasten; Nicholas (Santa Barbara, CA), Scott; Jeffrey S. (Goleta, CA), Strandemar; Katrin (Rimbo, SE), Nussmeier; Mark (Goleta, CA), Kurth; Eric A. (Santa Barbara, CA), Hoelter; Theodore R. (Goleta, CA), Boulanger; Pierre (Goleta, CA), Sharp; Barbara (Santa Barbara, CA)
Issued: April 25, 2017
Assignee: FLIR Systems, Inc. (Wilsonville, OR)