image which does not include the features of the clean windshield such as the vertical artifact line on the left side and the distortion marks in the upper right corner of the windshield as a result as shown in fig5 inherent distortions and defects present in the windshield and irrelevant to windshield wiper analysis have been eliminated from the u201c before and after u201d comparison developed from the intensity maps for each of respectively the soiled and poorly wiped windshield images thus as is evident from a review of fig1 5 the disclosed method can accurately identify surface regions indicating ineffective wiper function and distinguish these regions from background features in the windshield in addition to the graphical depictions illustrated in fig3 5 the system may be programmed to develop and display statistical information relating to the evaluation including for example indicators of the frequency of certain categories of types of problems resulting from poor wiper function similarly numerical or graphical standards which quantify the level of wiper performance may be developed and displayed if desired the analysis for each desired windshield image is illustrated in greater detail at the following described steps shown in fig6 once the windshield is mounted for analysis an image of the windshield is acquired at 33 using a ccd camera with the subject windshield positioned to allow the camera to capture an image of the windshield surface the resolved image data is then processed as further described below to identify and locate the objects materials visible on the.