Method of inspecting and manufacturing vehicle body

A method of inspecting a vehicle body, comprising the steps of:

• measuring a surface profile of a vehicle body, producing measured surface profile data;
• differentiating said measured surface profile data into linear differential data;
• smoothing said linear differential data into smoothed linear differential data;
• determining a central point of a distortion from said smoothed linear differential data and said linear differential data;
• determining the difference between reference surface profile data of the vehicle body and said measured surface profile data at said central point, as a degree of distortion;
• differentiating said linear differential data into quadratic differential data;
• determining a range of distortion around said central point from said quadratic differential data;
• and
• determining whether the distortion of the vehicle body is acceptable or not based on said degree of distortion and said range of distortion.

A method of inspecting a vehicle body, comprising the steps of:

• obtaining luminance data depending on a surface profile of a vehicle body from light reflected by a surface of the vehicle body irradiated with illuminating light;
• differentiating said luminance data into linear differential data;
• determining a central point of a distortion of the surface profile from said linear differential data;
• determining a range of distortion around said central point from said linear differential data;
• integrating said luminance data twice in said range of distortion, determining quadratic integral data;
• and
• determining a degree of distortion of said surface profile from said quadratic integral data.

A method of inspecting a vehicle body, comprising the steps of:

• measuring a surface profile of a vehicle body, producing measured surface profile data;
• determining deviation data between reference surface profile data of the vehicle body and said measured surface profile data at a predetermined pitch on the surface profile corresponding to a given location of the vehicle body;
• converting said deviation data into stepwise deviation data in a plurality of ranks;
• displaying said stepwise deviation data depending on the surface profile of the vehicle body, in different colors established with respect to the ranks, each of said displayed ranks corresponding to a different location of the vehicle body, respectively;
• and
• determining a surface distortion of the vehicle body, at said given location based on the stepwise deviation data displayed in said different colors.

A method of inspecting a vehicle body, comprising the steps of:

• measuring a surface profile of a vehicle body, producing measured surface profile data;
• determining deviation data between reference surface profile data of the vehicle body and said measured surface profile data at a predetermined pitch on the surface profile;
• establishing decision reference data based on at least a profile composed of said reference surface profile data in a range in which said deviation data is not nil, wherein a gradient of said decision reference data is greater as respective curvatures of said reference surface profile data and said measured surface profile data are greater in said range;
• and
• comparing said decision reference data and the deviation data in said range thereby to determine a surface distortion of the vehicle body.

A method of manufacturing a vehicle body, comprising:

• assembling outer panels on a vehicle frame, producing a vehicle body;
• coating an aqueous lustering agent diluted to a predetermined concentration ranging from 15 to 20% to a surface of said vehicle body under pneumatic pressure with a spray means, thereby forming a thin lustrous film on the surface of the vehicle body;
• measuring a degree of surface distortion of the surface of the vehicle body, including the outer panels;
• identifying a defective area of the surface by comparing said degree of surface distortion with a predetermined decision value, thereby determining whether said surface distortion is acceptable or not;
• if the defective area is not acceptable, repairing said defective area;
• and
• delivering the vehicle body with the defective area repaired to a coating station.