New-Tech Magazine - Europe | January Digital edition

expo-nential, or logarithmic, behavior of the human eye. HDR is helpful in traffic applications for subduing glaring reflections when reading license plates or countering the over exposure effects of bright headlights. The desired logarithmic response in a CMOS sensor can be achieved on-chip in several different ways: ● by sequential image capture using widely varying exposure times, thereby recording the light and dark areas separately, ● by equipping the sensor's odd and even rows with different sensitivi- ties for light and dark and calculating an appropriate average value for all regions of the image (Figure 6), or ● by using a piece-wise linear response (PLR), which delivers a more logarithmic ramping of the sensor's response curve (Figure 7). The user can choose the best suited method depending on the applica- tion, as they all have their specific benefits and drawbacks. Enhanced NIR Sensitivity Extending the spectral range of CMOS sensors to the near-infrared realm is becoming more and more important as a market trend (Figure 8). This especially applies to traffic applications but also to machine vision, because it allows the illumination of the scene to be monitored with flash lights that are invisible to the human eye. Pieter Willems is Manager Standard Products at CMOSIS in Antwerp, Belgium.

Figure 8: Enhanced sensor sensitivity in the near infrared, as demonstrated in the CMV family of CMOSIS.

Figure 9: The CMV Series sensors of CMOSIS were developed for machine-vision applications.

Table 1: Key specifications of the CMV Series.

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