Intelligent sensor method and apparatus for an optical wheel alignment machine

A method for generating data indicative of the orientation of a tire on a vehicle, comprising the steps of:

• (a) projecting shaped light onto a sidewall of a tire at a plurality of spaced locations,
• (b) receiving an image that includes portions of the shaped light reflected at an angle off said sidewall from each of said plurality of spaced locations,
• (c) generating a video signal that comprises a stream of pixel intensity levels arranged into successive groups of said pixel intensity levels, each of said groups representing a row of an array of pixels intensity levels that together represent said image,
• (d) providing a threshold intensity level that is less than those of said pixel intensity levels that represent said reflected portions of the shaped light,
• (e) determining a plurality of pixel counts by repeating the following steps (e1) through (e3) for each of a plurality of said groups of pixel intensity levels:
• (e1) comparing, in real time, said threshold intensity level with at least some of the pixel intensity levels of one of said groups,
• (e2) generating a logic signal when one of said pixel intensity levels exceeds said threshold intensity level, and
• (e3) determining, in response to an occurrence of said logic signal, one of said pixel counts in accordance with the position of said one of said pixel intensity levels within said one of said groups, and
• (f) using said pixel counts to generate output data representative of the spatial position of said plurality of spaced locations.

In a sensor for use in a wheel alignment machine to measure the orientation of a tire on a vehicle to thereby determine one or more alignment characteristics of the vehicle, said sensor being of the type having at least one light source oriented to project shaped light onto a sidewall of the tire at a plurality of spaced locations and a light responsive receiver oriented at a perspective angle with respect to said light source to receive an image that includes a portion of the shaped light that is reflected off the tire, with said light responsive receiver being operable to generate electrical signals indicative of the image, wherein the improvement comprises:

• an event-driven microprocessor circuit connected to receive said electrical signals from said light responsive receiver, said circuit including a microprocessor having an interrupt input;
• and
• a system of optical elements oriented relative to said light responsive receiver to provide said light responsive receiver with an optical view that includes the plurality of spaced locations of the tire, whereby portions of the shaped light that are reflected off the tire at each of the plurality of spaced locations are received by said light responsive receiver as a single image;
• said circuit being operable, in response to detecting in real time the presence within the image of the reflected portion of the shaped light, to generate an interrupt request on said interrupt input.

In an optical sensor for generating data indicative of a spatial attribute of an object, said sensor being of the type having at least one light source oriented to project shaped light onto the object at a plurality of spaced locations and a light responsive receiver oriented at a perspective angle with respect to said light source to receive an image that includes a portion of the shaped light that is reflected off the object, with said light responsive receiver being operable to generate electrical signals indicative of the image, wherein the improvement comprises:

• an event-driven microprocessor circuit connected to receive said electrical signals from said light responsive receiver, said circuit including a microprocessor having an interrupt input;
• and
• a system of optical elements oriented relative to said light responsive receiver to provide said light responsive receiver with an optical view that includes the plurality of spaced locations of the object, whereby portions of the shaped light that are reflected off the object at each of the plurality of spaced locations are received by said light responsive receiver as a single image;
• said circuit being operable, in response to detecting in real time the presence within the image of the reflected portion of the shaped light, to generate an interrupt request on said interrupt input.