Prior art emission spectra of light sources utilized in chromatic confocal sensors share two disadvantages: the uneven spectral power distribution (SPD) and the fixed distribution characteristic. Consequently, the detected peak signal intensity is regulated by the SPD properties of the light source and the spectrum transmittance characteristics of the dispersive lens. To achieve this, 18 types of monochromatic light-emitting diodes (LEDs) with different peak wavelengths were selected to create a wide-spectrum light source with a tunable SPD. The SPD characteristics of the light source can be modified by adjusting the luminous intensity of each LED. The tungsten halogen lamp, the “white” LED, and the designed light source were selected as the light sources for the chromatic confocal measurement system, respectively. Comparing the peak signals obtained under various light sources. The experimental results show that, in the range of 400 to 700 nm, the peak signal intensity extreme value ratio measured with the designed light source is 1.81:1, and the normalized light intensity standard deviation is 0.118. The corresponding light intensity extreme value ratio of halogen tungsten lamp and white LED is 23.3:1, 300:1, and the normalized light intensity standard deviation is 0.302, 0.228. With the help of the designed light source, a group of wave crest signals with uniform light intensity distribution can be obtained. This can reduce the influence of the SPD characteristics of the light source itself and the transmissivity characteristics of the dispersive objective lens on the measured signal, and ensure the accuracy of spectral detection.
For Dynamic Vision Sensors (DVS), thermal noise and junction leakage current induced Background Activity (BA) is the major cause of the deterioration of images quality. Inspired by the smoothing filtering principle of horizontal cells in vertebrate retina, A DVS pixel with Neighbor Pixel Communication (NPC) filtering structure is proposed to solve this issue. The NPC structure is designed to judge the validity of pixel’s activity through the communication between its 4 adjacent pixels. The pixel’s outputs will be suppressed if its activities are determined not real. The proposed pixel’s area is 23.76×24.71μm2 and only 3ns output latency is introduced. In order to validate the effectiveness of the structure, a 5×5 pixel array has been implemented in SMIC 0.13μm CIS process. 3 test cases of array’s behavioral model show that the NPC-DVS have an ability of filtering the BA.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.