Exhibit 23 Grant Thornton Letterhead CONSENT OF INDEPENDENT REGISTERED CERTIFIED PUBLIC ACCOUNTING FIRM We have issued our report dated August 13, 2004 accompanying the consolidated financial statements of Perceptron, Inc. and Subsidiaries appearing in the Annual Report on Form 10-K for the year ended June 30, 2004. We consent to the incorporation by reference in the Registration Statements of the Company on Form S-3 (Registration Nos. 333-24239 and 333-29263) and on Form S-8 (Registration Nos. 33-63664, 33-85656, 33-93910, 333-00444, 333-00446, 333-65001, 333-65007, 333-92643, 333-92645, 333-92647, 333-55164, 333-76194 and 333-104040) of the aforementioned report. /s/ GRANT THORNTON LLP Southfield, Michigan September 24, 2004