An IR autofocus system has emitter and detector apertures separated by 1cm and modeled as pin holes.The light reflected from an object at range r casts a spot that is detected at a displacement of 0.1mm from the detector axis.The detector lies 0.5cm behind the pin hole.The value of r equals _____ $\text { (x.x m) }$

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The Answer is

\mathrm { f } = 5 imes 10 ^ { - 3 } \mathrm {~m} , \mathrm {~s} = 10 ^ { - 2 } \mathrm {~m} , \mathrm { x } = 10 ^ { - 4 } \mathrm {~m} , \mathrm { r } / \mathrm { s } = \mathrm { f } / \mathrm { x } ightarrow \mathrm { r } = \mathrm { sf } / \mathrm { x } = \left( 10 ^ { - 2 } \mathrm {~m} ight) \left( 5 imes 10 ^ { - 3 } \mathrm {~m} ight) / \left( 10 ^ { - 4 } \mathrm {~m} ight) = 5 \mathrm { x }

10 ^ { - 1 } \mathrm {~m} = 0.5 \mathrm {~m} ext {. }

An IR Autofocus System Has Emitter and Detector Apertures Separated (x.x m) \text { (x.x m) } (x.x m)

An IR Autofocus System Has Emitter and Detector Apertures Separated $\text { (x.x m) }$