177 dB linear dynamic range pixels of interest DSLR CAOS camera

For the first time, demonstrated is an extreme linear Dynamic Range (DR) Pixels of Interest (POI) [i.e., Coded Access Optical Sensor (CAOS)] Digital Single Lens Reflex (DSLR) camera design that engages three different types of photosensors within one optomechanical assembly to smartly identify POI across a one billion to one light irradiance range. A pixelated CMOS sensor provides a limited DR and linearity image by engaging a moveable mirror placed between the Digital Micromirror Device (DMD) and the frontend imaging lens. Next using DMD control, non-POI light is directed away from the chosen point photodetector (PD) engaged for high DR POI image recovery, giving the PD an improved use of quantum well capacity. For brighter POI, a solid state photodiode point PD with an electronic gain controlled amplifier is engaged while for weaker light POI, a photomultiplier tube (PMT) with variable optical gain is deployed. POI imaging is achieved using time-frequency CAOS modes via DMD control and time-frequency correlation and spectral digital signal processing. A 123.4 dB linear DR POI recovery is achieved for a custom incoherent white light 36-patch target while a record 177 dB linear DR recovery is demonstrated for a single patch 633 nm laser target. For the first time, a 1023 POI frame, real-time 48 frames/s update rate CAOS imaging is demonstrated for tracking a changing focal spot moving laser target

Demonstration of the CDMA-mode CAOS smart camera

Demonstrated is the code division multiple access (CDMA)-mode coded access optical sensor (CAOS) smart camera suited for bright target scenarios. Deploying a silicon CMOS sensor and a silicon point detector within a digital micro-mirror device (DMD)-based spatially isolating hybrid camera design, this smart imager first engages the DMD starring mode with a controlled factor of 200 high optical attenuation of the scene irradiance to provide a classic unsaturated CMOS sensor-based image for target intelligence gathering. Next, this CMOS sensor provided image data is used to acquire a focused zone more robust un-attenuated true target image using the time-modulated CDMA-mode of the CAOS camera. Using four different bright light test target scenes, successfully demonstrated is a proof-of-concept visible band CAOS smart camera operating in the CDMA-mode using up-to 4096 bits length Walsh design CAOS pixel codes with a maximum 10 KHz code bit rate giving a 0.4096 seconds CAOS frame acquisition time. A 16-bit analog-to-digital converter (ADC) with time domain correlation digital signal processing (DSP) generates the CDMA-mode images with a 3600 CAOS pixel count and a best spatial resolution of one micro-mirror square pixel size of 13.68 μm side. The CDMA-mode of the CAOS smart camera is suited for applications where robust high dynamic range (DR) imaging is needed for un-attenuated un-spoiled bright light spectrally diverse targets

The CAOS Camera - unleashing the power of full spectrum extreme linear dynamic ranging imaging

The CAOS camera invention is described that allows high security full spectrum (350 nm to 2700 nm) extreme linear dynamic range bright target imaging. First time experiments highlight real-time simultaneous tracking of bright visible and infrared laser beams

96 dB linear high dynamic range CAOS spectrometer demonstration

For the first time, a CAOS (i.e., Coded Access Optical Sensor) spectrometer is demonstrated. The design implemented uses a reflective diffraction grating and a time-frequency CAOS mode operations Digital Micromirror Device (DMD) in combination with a large area point photo-detector to enable highly programmable linear High Dynamic Range (HDR) spectrometry. Experiments are conducted with a 2850 K color temperature light bulb source and visible band color bandpass and high-pass filters as well as neutral density (ND) attenuation filters. A ~369 nm to ~715 nm input light source spectrum is measured with a designed ~1 nm spectral resolution. Using the optical filters and different CAOS modes, namely, Code Division Multiple Access (CDMA), Frequency Modulation (FM)-CDMA and FM-Time Division Multiple Access (TDMA) modes, measured are improving spectrometer linear dynamic ranges of 28 dB, 50 dB, and 96.2 dB, respectively. Applications for the linear HDR CAOS spectrometer includes materials inspection in biomedicine, foods, forensics, and pharmaceuticals

Demonstration of CAOS smart camera imaging for color and super blue moon targets

Highlighted is the CAOS smart camera design suited for extreme dynamic range sensing. Experiments for the first time show CAOS imaging of a visible band color target and the super blue moon observed in Ireland

Robust testing of displays using the extreme linear dynamic range CAOS camera

Proposed and demonstrated for the first time is robust testing of optical displays using the extreme linear Dynamic Range (DR) CAOS camera. Experiments highlight accurate and repeatable CAOS camera-based testing of standard 8-bit (i.e., 48 dB DR) and modified DR 10-bit (i.e., 60 dB DR) computer Liquid Crystal Displays (LCDs). Results are compared with CMOS camera and light meter-based LCD testing highlighting the robustness of the CAOS camera readings

CAOS module designs and imaging

In this dissertation, proposed and demonstrated are the various novel CAOS module designs and imaging modes that offer a wide range of imaging capabilities suited to various imaging scenarios. The CAOS modules designs include the use of several commercially available electrical and optical components that are controlled through custom in-lab built software for image capture, reconstruction, and post-processing. The first chapter introduces the novel Code Division Multiple Access (CDMA) mode of the camera that is best suited for high Signal-to-Noise (SNR) imaging of bright light targets in minimal acquisition time. Theoretical and experimental comparisons of CDMA mode to the previously well-known Hadamard Transform imaging are also presented, showcasing the advantages of the CAOS-CDMA mode. The next part of this dissertation introduces several novel hybrid CAOS Camera imaging modes, which include Time Division Multiple Access (TDMA), CDMA-TDMA, Frequency Modulation (FM)-TDMA, Frequency Division Multiple Access (FDMA)-TDMA, and FM-CDMA-TDMA. A thorough explanation of the workings of each of these modes with their performance trade-offs has been included as well. Experimental demonstrations include the use of the CAOS camera for laser beam spot size measurement using different imaging modes. To demonstrate the power of CAOS, FM-TDMA mode is used to capture the oscillatory behavior of a Gaussian beam up to a Dynamic Range (DR) of 94.9 dB. This oscillatory behavior is also predicted and confirmed by the Huygens-Fresnel diffraction theory. The performance limits of these modes are further tested and evaluated against a commercially produced Image Engineering custom made uniformly lit 160 dB High Dynamic Range (HDR) target. DR recovery limit and SNR performance are also evaluated for a Quantalux HDR sCMOS sensor which is incorporated within a new Digital Single Lens Reflex (DSLR) design of the CAOS camera. Experiments confirming the superior HDR linear performance of CDMA and FM-TDMA mode in comparison to the sCMOS are also presented. A record 177 dB linear DR response using a controlled laser pixel using electronic amplification and Digital Signal Processing (DSP) is also reported. In addition, a 48 Pixels of Interest frames per second video sample is also recorded for tracking a moving laser beam spot. Another key aspect of any imaging camera is the ability to resolve a low contrast image over an HDR target. Such targets are ever-present in daily life and hence for robust operation, a high-end sensor must be capable of imaging such scenes. Two CMOS sensors, namely the 2.1 MP Quantalux sCMOS sensor, and the EMVA1288 compliant Photonfocus CMOS HDR sensor are tested against an in-house built 90 dB HDR target. This target has 16 discrete irradiance levels while maintaining a 2:1 relative irradiance across the entire DR of the target. Inspection of the experimentally measured target data reveals partial linear recovery up to 42 dB, whereas the weaker target regions were also registered by the Quantalux CMOS sensor but for these, recovery was non-linear. Highly accurate, linear HDR performance was recorded when engaging CAOS FM-TDMA mode. Thus, the proposed operation of the CAOS camera ensures accurate recovery of a low contrast HDR target which might be critical in applications related to imaging and display testing. The previously mentioned designs of the CAOS camera rely on passive imaging of targets, where the target emits/reflects light, and this light is imaged via an imaging lens onto the imaging sensor. Alternatively, a design variant of the CAOS camera uses a hybrid method of combining optical device engagement and time-frequency CAOS operations whereby the SLM and the illuminating source work in unison to deliver the FM-CDMA mode of the camera. Specifically, the illuminating source must-have modulation capabilities that allow frequency modulation of the light source providing FM encoding whereas the SLM is used to implement CDMA Walsh codes for pixel irradiances. Indeed this mode of operation preserves the linear high DR imaging capabilities of CAOS and experiments conducted with a calibrated target indicate a near 60 dB linear DR using a white light imaging target. The last part of this dissertation covers the CAOS line camera, a linear HDR CAOS spectrometer, and a 2-D spectral imager. The CAOS line camera design relies on the use of a 1-D SLM for time-frequency modulation instead of the previously demonstrated 2-D SLM based CAOS camera. The line camera design incorporates the use of a Galvo system with a feedback control system for precise image translation over the 1-D SLM. The introduction of a Galvo system mitigates the need for a mechanical motion of the camera thereby reducing imaging artifacts. An increase in the Field-of-View (FOV) is also recorded. Potential applications involve broadband operation from Ultra-Violet to Infrared regimes, high linear dynamic range target recovery, and robust low contrast imaging. Next, a design of the CAOS spectrometer utilizing a dispersive grating is introduced for spectral content analysis. The advantages of the CAOS platform in spectrometry are two-fold (i) it delivers linear HDR spectral measurements, and (ii) high SNR performance due to simultaneous encoding of multiple spatial-spectral regions. The highly adaptive and programmable nature of the CAOS platform allows inspection of any spectral band, UV, Visible, and Infrared. This design of the CAOS spectrometer is further modified to enable 2-D spectral imaging. The design relies on line scan mechanism to sequentially image the target. Experiments conducted include imaging of a vertical slit, which mimics a line target. Additionally, a frequency channel criterion to choose FDMA frequencies, which minimize inter-channel crosstalk, is also presented. In comparison to FM-TDMA, this criterion allows minimization of imaging times significantly while ensuring no compromise on the complete recovery of an HDR scene

MEMS-based CAOS Smart Camera 177 dB Linear Extreme Dynamic Range Imaging Tests with Calibrated and Controlled Incoherent White Light and Laser Light Targets

Highlighted are the linear extreme dynamic range calibrated target imaging tests of the CAOS smart camera showing a 177 dB linear dynamic range operation with an optical attenuation controlled bright laser targe

The CAOS Camera - unleashing the power of full spectrum extreme linear dynamic ranging imaging

The CAOS camera invention is described that allows high security full spectrum (350 nm to 2700 nm) extreme linear dynamic range bright target imaging. First time experiments highlight real-time simultaneous tracking of bright visible and infrared laser beams