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False alarms are also common with smoke detectors and building fire alarm systems. They occur when smoke detectors are triggered by smoke that is not a result of a dangerous fire. Smoking cigarettes, cooking at high temperatures, burning baked goods, blowing out large numbers of birthday candles, fireplaces and woodburners when used around a ...
Constant false alarm rate (CFAR) detection is a common form of adaptive algorithm used in radar systems to detect target returns against a background of noise, clutter and interference. [ 1 ] Principle
The false positive rate (FPR) is the proportion of all negatives that still yield positive test outcomes, i.e., the conditional probability of a positive test result given an event that was not present. The false positive rate is equal to the significance level. The specificity of the test is equal to 1 minus the false positive rate.
To reduce false alarms this type of detector is usually combined with a passive infrared detector or similar alarm. Compared to the monostatic, the bistatic units work over longer distances: typical distances for transmitter-receivers up to 200 m for X-band frequencies and up to 500 m for K-band frequencies.
False-alert filtering: Sometimes, radar detectors will mistakenly detect radar signals from other devices. There are a number of variables that can trigger false alerts, from sensors on another ...
In addition, false alarms may acclimatise people to ignore alarm signals, and thus possibly to ignore an actual emergency: Aesop's fable of The Boy Who Cried Wolf exemplifies this problem. A false alarm is one of the most significant issues with conventional alarm systems. They can be triggered for several reasons, such as the movement of pets ...
This detector's displays are also basic, including a “Bogey Counter” that combines an array of functions: the number of false alarms or “bogies," sensitivity-mode indicator, laser warning ...
The plastic window reduces the chance of foreign objects (dust, insects, rain, etc.) from obscuring the sensor's field of view, damaging the mechanism, and/or causing false alarms. The window may be used as a filter, to limit the wavelengths to 8-14 micrometres, which is closest to the infrared radiation emitted by humans.