Patent ID: 8319950

Claim:
A laser light receiver, comprising: a processing circuit, at least one photosensor, a variable sensitivity control circuit, an output circuit, and at least one optical filter; wherein: (a) said at least one optical filter exhibits an optical characteristic so as to allow only wavelengths of electromagnetic energy at predetermined transmittance characteristics to pass therethrough to impact upon said at least one photosensor, such that said predetermined transmittance characteristics sufficiently pass wavelengths in both the green and red visible light ranges; (b) said at least one photosensor exhibits a predetermined frequency sensitivity characteristic so as to be sufficiently sensitive to electromagnetic energy in both the green and red visible light ranges; and said at least one photosensor, after receiving a sufficient amount of electromagnetic energy that impacts thereon, outputs at least one first signal to said variable sensitivity control circuit, which modifies said at least one first signal according to a gain state of said variable sensitivity control circuit to produce at least one second signal, and outputs said at least one second signal to said processing circuit; and (c) said laser light receiver is configured: (i) to evaluate said at least one second signal and, based upon a value of said at least one second signal, to determine a relative elevation of said at least one photosensor with respect to received electromagnetic energy that impacts thereon, and, using said output circuit, to output a third signal to provide an indication of said determined relative elevation; and (ii) to effectively reject an unwanted interference light signal that may be included in said at least one second signal, by inhibiting an output of said third signal by said output circuit and thereby preventing an indication of said determined relative elevation due to such unwanted interference light signal; wherein: said laser light receiver is further configured to determine said gain state of the variable sensitivity circuit, and to output said third signal for indicating said relative elevation based on that determined gain state; and said laser light receiver is further configured to effectively reject the unwanted interference light signal at a rejection rate that is determined by said gain state.