1. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Pixel layouts for (a) a standard 3-T APS containing reset (R), row select (RS) and source follower (SF) transistors with voltage supply VDD and reset voltage VR lines; (b) Vanilla, in addition to the layout of (a) includes flushed reset circuitry; and (c) OPIC, showing the advanced “DFF” array with transfer gate (TX), comparator, two 8-bit DRAMs, an 8-bit ROM, and 1-bit hit flag per pixel, along with threshold voltage supply Vth. Note pixel boundaries are denoted by a dashed line. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

2. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Block diagram of the Vanilla sensor. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

3. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Block diagram of the OPIC sensor. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

4. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Diagram of the OPIC array architecture illustrating the column mirroring employed to maximize fill factor, and the repeater pixels whose hit flags are always set to 1 to ensure data integrity. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

5. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Relationship between the 12-bit global DAC and pixel voltage for the digital pixel sensor OPIC. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

6. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Sensor pixel voltage variation with increasing integration time under no illumination. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

7. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Photon transfer curves measured for Vanilla and OPIC. For clarity, only hard reset results are displayed for OPIC and total noise curves including fixed pattern noise components are omitted. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

8. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Spectral response of Vanilla to input illumination across the optical range. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

9. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Spectral response of OPIC to input illumination across the optical range. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

10. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Vanilla response to x-ray flux at diagnostic energies when coupled to 150μm of CsI:Tl with a 3-mm fiber optic plate. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

11. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. OPIC response to x-ray flux at diagnostic energies when coupled to 100μm of structured CsI:Tl with a 1-mm fiber optic plate. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

12. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. MTFs of both sensors when coupled to different structured CsI:Tl scintillators. The resulting MTF is largely dominated by the choice of scintillator. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

13. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Demonstration of ROI readout in Vanilla using optical illumination. A blade rotating at approximately 3.5Hz was used to obscure the sensor from a light source. Full frame readout at 4frames∕s shown in (a) is too slow to visualize the edge of the blade. Smaller ROIs read out at higher rates so the clarity of the blade edge improves. A 100×100 region is shown in (b), a 50×50 region in (c), and a 10×200 region in (d). Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

14. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Profiles across the blade edge (in pixels) illustrates the increase in the sampling frequency with decreasing ROI size. The width of the edge is 33 pixels in Fig. and only 7 in (d). Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

15. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Vanilla x-ray image of a breast tissue phantom composed of excised breast tissue fixed in formalin. A position marker can be seen in bottom left corner. The ROI marked on the full-frame image is 200×200 in size. The ROI readout is shown in the right on the same grayscale for comparison of features. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

16. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Demonstration of OPIC intelligent readout modes using optical illumination with a loop of wire partially obscuring the sensor: (a) ADC signal recorded by the sensor at a 164-μs integration time (the area outside of the loop is saturated); (b) time taken for each pixel to reach the threshold voltage set at the saturation level, the brighter the result, the longer the time taken; and (c) sparse image where 1 (black) represents a pixel whose hit flag has been set (i.e., it has crossed the threshold) and 0 (white) represents a pixel that has not been hit. Note the two vertical lines are due to repeater pixels that are always set to hit to ensure data integrity. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224

17. Date of download: 6/23/2016 Copyright © 2016 SPIE. All rights reserved. Application of OPIC intelligence to x-ray imaging of a tube of iodine contrast agent. Iodine is used to enhance the contrast of blood vessels in the body relative to the surrounding tissue: (a) and (b) Grayscale ADC signals at 66 and 164ms, respectively (saturation occurs at 128DN in 7-bit ADC); (c) time in seconds taken for each pixel to reach saturation (brighter implies a longer time); (d) to (f) to sparse image of hit flags at integration times of 66, 164, and 328ms, respectively, when the threshold was set at pixel saturation. Figure Legend: From: Characterization studies of two novel active pixel sensors Opt. Eng. 2007;46(12):124003-124003-11. doi:10.1117/1.2818224