


                                    EXHIBIT 4

                          AMENDMENT TO CLASS I WARRANT

     THIS  AMENDMENT  TO THE CLASS I WARRANT TO  PURCHASE  CLASS A COMMON  STOCK
("Amendment")  is made and  entered  into as of the 5th day of June  1998 by and
among Advanced Machine Vision Corporation,  a California corporation ("Company")
on the one hand, and Veneer Technology,  Inc. (formerly Ventek, Inc.), an Oregon
corporation  ("Veneer")  and Rodger A. Van  Voorhis,  Douglas  Hickman,  Kenneth
Winder and Thomas Thompson (collectively, the "Shareholders") on the other hand.

     WHEREAS,  the Class I Warrant was issued by the Company in connection  with
that  certain  Asset  Purchase  Agreement  dated July 24,  1996 by and among the
Company, Veneer and the Shareholders;

     WHEREAS,  the  parties  desire to amend the Class I Warrant  to adjust  the
number of shares of Class A Common Stock  issuable  upon exercise of the Class I
Warrant due to the failure of Ventek,  Inc. to meet  certain  sales and earnings
goals set forth in the Class I Warrant;

     WHEREAS,  it is in the best interests of the parties to adjust such Warrant
to further simplify the Company's capital structure.

     NOW THEREFORE,  in consideration  of the premises and the  representations,
warranties and agreements herein contained, the parties hereby agree as follows:

     1.  Veneer and the Shareholders represent that they have the legal right to
         execute this Amendment.

     2.  Veneer and the  Shareholders  have not assigned or pledged in the past,
         nor will they in the  future  assign or  pledge,  any  right,  title or
         interest in the Class I Warrant or this Amendment.

     3.  The number of shares of Class A Common Stock  issuable  pursuant to the
         Class I Warrant is changed from 1,000,000 to 250,000.

     4.  Section 2 of the Class I Warrant is hereby deleted in its entirety.

     5.  Section 1(d) is amended to read: "`Initial Warrant Exercise Date' shall
         mean March 31, 1997."

     IN WITNESS  WHEREOF,  the parties  hereto have caused this  Amendment to be
executed by their respective duly authorized officers as of the date first above
written.


                                             ADVANCED MACHINE VISION CORPORATION



                                             By:  /s/ Alan R. Steel
                                                --------------------------------
                                                Alan R. Steel
                                                Vice President, Finance and CFO



                                             VENEER TECHNOLOGY, INC.



                                             By:  /s/ Rodger A. Van Voorhis
                                                --------------------------------
                                                Rodger A. Van Voorhis
                                                President


                                             SHAREHOLDERS


                                                /s/ Douglas Hickman
                                                --------------------------------
                                                Douglas Hickman



                                                /s/ Kenneth Winder
                                                --------------------------------
                                                Kenneth Winder



                                                /s/ Thomas Thompson
                                                --------------------------------
                                                Thomas Thompson



                                                /s/ Rodger A. Van Voorhis
                                                --------------------------------
                                                Rodger A. Van Voorhis



