Document:

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                                                                    Exhibit 10.5

                                PERCEPTRON, INC.
                       EXECUTIVE AGREEMENT NOT TO COMPETE

     I recognize that Perceptron, Inc., a Michigan corporation, and its direct
and indirect subsidiaries, whether now in existence, or hereafter acquired or
created, (including, but not limited to, Perceptron B.V., Perceptron GmbH,
Perceptron Canada, Inc., Peceptron Global, Inc. and Perceptron Brazil, LLC)
(collectively, the "Company"), desires to insure that I do not compete with the
Company, as specified below.

     In consideration of the Company's employment of me, and other good and
valuable consideration, the receipt of which is hereby acknowledged, I agree as
follows:

     1. During the term of my employment by the Company (which period shall be
referred to as "my Engagement"), and thereafter during the longer of (i) any
period in which the Company is obligated to make payments to me (the "Payment
Completion Period"), or (ii) 12 months from the end of my Engagement (the
"Non-Compete Period"), I shall not engage, directly or indirectly, as officer,
director, shareholder, partner, member, associate, consultant, owner, agent,
independent contractor, employee or otherwise of any person, firm, corporation
or other business engaged, anywhere in the world, (i) in any business conducted
by the Company during my Engagement, or any business which I was aware, during
my Engagement, that the Company planned to engage in, or (ii) in any business
involving the design, development, manufacture, sale or servicing of machine
vision sensors and systems utilizing electro-optical techniques or component
parts utilized in such sensors or systems (the "Non-Compete Provisions");
provided that the ownership of one (1%) percent or less of the stock in any
publicly traded corporation in such a business shall not be violative of the
foregoing covenant. In the event that I shall fail to comply with any of my
obligations under this Agreement, in addition to any other remedies that the
Company may have at law or in equity, my employment with the Company as an
employee shall automatically terminate and the Company's obligations to me shall
automatically terminate, including any obligations of the Company to me for
severance or other compensation or benefits following termination of my
Engagement.

     2. I understand that nothing in this Agreement shall affect my obligations
under the "Proprietary Information and Inventions Agreement" between the Company
and myself dated ____________________.

     3. I shall notify the Company, during the Non-Compete Period of any change
in my address and each subsequent employment or business activity (stating the
name and address of the employer or business, the nature of the business of such
employer or business and the nature of my position) in which I engage during
such Non-Compete Period.

     4. I acknowledge that this Agreement embodies the entire agreement and
understanding between the parties hereto and there are no other agreements or
understandings, oral or written, between the parties hereto with respect to the
subject matter hereof, and, that this Agreement shall supersede all previous
agreements, negotiations, commitments and writings with respect to the subject
matter hereof. No waiver and no modification or amendment of any
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provision of this Agreement shall be effective unless specifically made in
writing and duly signed by the party to be bound thereby.

     5. I hereby acknowledge that, in the event any provision of this Agreement
or portion thereof is found to be wholly or partially invalid, illegal or
unenforceable in any judicial proceeding, then such provision shall be deemed to
be modified or restricted to the extent and in the manner necessary to render
the same valid and enforceable, or shall be deemed excised from this Agreement,
as the case may require, and this Agreement shall be construed and enforced to
the maximum extent permitted by law, as if such provision had been originally
incorporated herein as so modified or restricted, or as if such provision had
not been originally incorporated herein, as the case may be.

     6. I acknowledge that the Company may assign its rights under this
Agreement to any affiliate or any person who acquires or succeeds to any part of
the business or assets of the Company.

     7. I acknowledge that if there is a breach or threatened breach of the
provisions of this Agreement, the Company shall be entitled to an injunction
restraining me from such breach, in addition to any other remedies available to
the Company for such breach or threatened breach.

     8. I acknowledge that this Agreement may be executed in one or more
counterpart copies; each of those fully executed copies shall be considered as
original, but together shall constitute one agreement.

     9. I acknowledge that this Agreement has been negotiated, executed, and
delivered in, and will be governed by the laws of, the State of Michigan,
without regard to the conflict or choice of law principles of that state which
might otherwise be applicable, and I acknowledge and agree to submit to the
jurisdiction of the courts of and in the State of Michigan with respect thereto.

Date:                                   By:
      -------------------------------       ------------------------------------

ACCEPTED AND AGREED TO:

PERCEPTRON, INC., on its own behalf
and on behalf of its subsidiaries,
whether now in existence or hereafter
acquired or created.

By:
    ---------------------------------
Title:
       ------------------------------

                                        2<PAGE>
                                                                     Exhibit 4.1

                              WILLBROS GROUP, INC.

                                       AND

                           JPMORGAN CHASE BANK, N.A.,
                    SUCCESSOR TO JPMORGAN CHASE BANK, TRUSTEE

                           --------------------------

                          FIRST SUPPLEMENTAL INDENTURE

                         DATED AS OF SEPTEMBER 22, 2005

                              TO THE INDENTURE FOR
                     $70,000,000 AGGREGATE PRINCIPAL AMOUNT
                                       OF
                     2.75% CONVERTIBLE SENIOR NOTES DUE 2024
                           DATED AS OF MARCH 12, 2004

                          ----------------------------

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         FIRST SUPPLEMENTAL INDENTURE, dated as of September 22, 2005 (the
"EFFECTIVE DATE"), between WILLBROS GROUP, INC., a Panamanian corporation (the
"COMPANY") and JPMORGAN CHASE BANK, N.A., successor to JPMORGAN CHASE BANK, as
trustee (the "TRUSTEE").

                             RECITALS OF THE COMPANY

         WHEREAS, the Company has duly issued 2.75% Convertible Senior Notes due
2024 in the aggregate principal amount of $70,000,000 (the "NOTES") pursuant to
an Indenture dated as of March 12, 2004, between the Company and the Trustee
(the "ORIGINAL INDENTURE"), and the Notes are outstanding on the date hereof;

         WHEREAS, the Company has received the written consent from Holders (as
defined in the Indenture) of a majority in aggregate principal amount
outstanding of the Notes to certain amendments to the Original Indenture upon
the terms set forth in the Company's Consent Solicitation Statement dated
September 8, 2005 and the accompanying Letter of Consent;

         WHEREAS, Section 11.2 of the Original Indenture provides that, with the
consent of the Holders of at least a majority of the principal amount of the
Notes outstanding, the Company and the Trustee may amend the Original Indenture;

         WHEREAS, the Board of Directors of the Company has by memorandum of
action upon unanimous consent dated as of September 6, 2005 authorized the
execution and delivery of this first supplemental indenture dated as of
September 22, 2005 (the "SUPPLEMENTAL INDENTURE"); and

         WHEREAS, Section 11.7 of the Original Indenture provides that upon the
execution of a supplemental indenture, the Original Indenture shall be modified
in accordance therewith, and every Holder of Notes shall be bound thereby.

         NOW, THEREFORE, the parties hereto agree as follows:

                                    ARTICLE 1
                DEFINITIONS AND PROVISIONS OF GENERAL APPLICATION

         SECTION 1.01. Effective Date. This Supplemental Indenture with respect
to the Notes is effective as of the Effective Date.

         SECTION 1.02. Definitions. The Original Indenture together with this
Supplemental Indenture are hereinafter sometimes collectively referred to as the
"INDENTURE." For the avoidance of doubt, references to any "Section" of the
"Indenture" refer to such Section of the Original Indenture as supplemented and
amended by this Supplemental Indenture. All capitalized terms which are used
herein and not otherwise defined herein are defined in the Original Indenture
and are used herein with the same meanings as in the Original Indenture. If a
capitalized term is defined in the Original Indenture and this Supplemental
Indenture, the definition in this Supplemental Indenture shall apply to the
Indenture and the Notes.

         SECTION 1.03. Provisions of the Indenture. Except insofar as herein
otherwise expressly provided, all the definitions, provisions, terms and
conditions of the Original Indenture shall remain in full force and effect. The
Original Indenture as modified by this Supplemental Indenture is in all respects
ratified and confirmed, and the Original Indenture and this Supplemental
Indenture shall be read, taken and considered as one and the same instrument for
all purposes and every Holder of Notes authenticated and delivered under the
Indenture shall be bound hereby.

                                       2
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                                    ARTICLE 2
                   AMENDMENTS TO SECTION 1.1 OF THE INDENTURE

         Section 1.1 of the Indenture is hereby amended to insert alphabetically
the following terms:

                  "CASH TAKE-OVER TRANSACTION" has the meaning provided in
         Section 5.1(e).

                  "COUPON MAKE-WHOLE PAYMENT" means a payment equal to the
         present value (which the Company shall cause to be calculated and
         provided to the Trustee) of the lesser of (i) two years of scheduled
         payments of interest on the Notes from the date of the Cash Take-Over
         Transaction or (ii) all scheduled payments of interest on the Notes
         which are payable for the period from the date of the Cash Take-Over
         Transaction through March 15, 2013, which present value will be
         computed using a discount rate equal to the Treasury Rate, as of the
         date of such Cash Take-Over Transaction.

                  "SOLICITATION DOCUMENTS" means the Consent Solicitation
         Statement dated September 8, 2005 and the related Letter of Consent,
         each as may be amended and supplemented from time to time.

                  "TREASURY RATE" means the yield to maturity, as of the date of
         the applicable Cash Take-Over Transaction, of United States Treasury
         securities (as compiled and published in the most recent Federal
         Reserve Statistical Release H.15 (519) that has become publicly
         available prior to the date of such Cash Take-Over Transaction (or, if
         such Statistical Release is no longer published, any publicly available
         source of similar market data)) with a constant maturity most nearly
         equal to the shorter of (i) the two year period beginning on the date
         of the Cash Take-Over Transaction or (ii) the period from the date of
         the Cash Take-Over Transaction to March 15, 2013; provided, that if the
         period from the date of the Cash Take-Over Transaction to March 15,
         2013 is less than one year, the weekly average yield on actually traded
         United States Treasury securities adjusted to a constant maturity of
         one year will be used.

                                    ARTICLE 3
                   REVISION TO SECTION 3.1(i) OF THE INDENTURE

         Section 3.1(i) of the Indenture is hereby deleted and replaced in its
entirety with the following:

         "(i) all or a portion of the Notes, beginning on March 15, 2013, at a
         Redemption Price equal to 100% of the principal amount of the Notes
         plus accrued and unpaid interest, Additional Amounts and Additional
         Interest, if any, to, but not including, the Redemption Date; and"

                                    ARTICLE 4
                    AMENDMENT TO SECTION 5.1 OF THE INDENTURE

         4.01 Article V of the Indenture is hereby amended by changing the
heading of Article V to read "FUNDAMENTAL CHANGE."

         4.02 Section 5.1 is hereby amended by changing the heading of Section
5.1 to read "Fundamental Change Put; Coupon Make-Whole Payment," and by
inserting the following terms as a new Section 5.1(e):

                  "(e) In connection with a Fundamental Change referred to in
         clause (iii) of the definition of Fundamental Change which occurs prior
         to March 15, 2013 and pursuant to which 10% or more of the fair market
         value for the consideration for the Voting Stock (excluding cash
         payments for fractional shares and cash payments made in respect of
         dissenters' appraisal rights) in the transaction or transactions
         otherwise constituting the Fundamental Change consists of cash (a "CASH
         TAKE-OVER TRANSACTION"), the Company will make, no later than 45 days
         after the date of notice of the occurrence of such Cash Take-Over
         Transaction, a Coupon Make-Whole Payment in cash, Common Stock (based
         on a price for the Common Stock which is equal to the average of the
         closing prices of the Common Stock for the five consecutive Trading
         Days prior to but not including the date on which the Cash Take-Over
         Transaction becomes effective), or a combination thereof at the
         Company's option. The Company's notice of the occurrence of a

                                       3
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         Cash Take-Over Transaction shall specify whether the Coupon Make-Whole
         Payment shall consist solely of cash or Common Stock or a combination
         thereof, and will specify the relative percentages of each if a
         combination is chosen.

         Not more than 30 days after the occurrence of a Cash Take-Over
Transaction, in the event a Coupon Make-Whole Payment is made in cash, either in
whole or in part, the Company shall use its best efforts to either (i) obtain
the consents under all existing indebtedness required to permit the Company to
make a Coupon Make-Whole Payment in cash pursuant to this Section 5.1(e), or
(ii) repay in full all existing indebtedness and terminate all commitments under
all existing indebtedness, in each case the terms of which would prohibit the
Company from making a Coupon Make-Whole Payment in cash.

         In the event the Coupon Make-Whole Payment is made in Common Stock,
either in whole or in part, the Company will comply with all United States
federal and state securities laws so as to permit the Company to make a Coupon
Make-Whole Payment in Common Stock pursuant to this Section 5.1(e)."

                                    ARTICLE 5
                    REVISION TO SECTION 6.2 OF THE INDENTURE

         Section 6.2(a) of the Indenture is hereby amended by inserting the
following after the first sentence:

                  "Solely with respect to the period beginning on the Effective
         Date and ending on the nine-month anniversary of the Effective Date,
         the Company shall be deemed to have complied with this Section 6.2(a)
         as long as it delivers to the Trustee the annual and quarterly reports,
         information, documents and other reports referred to in this Section
         6.2 within 15 days after they are filed with the SEC and
         notwithstanding any new or continuing failure on the part of the
         Company to file any such reports, information or documents with the SEC
         on or before their respective due dates as set forth in the rules and
         regulations of the SEC."

                                    ARTICLE 6
                                  MISCELLANEOUS

         SECTION 6.01. Integral Part. This Supplemental Indenture constitutes an
integral part of the Indenture.

         SECTION 6.02. Adoption, Ratification and Confirmation. The Indenture,
as supplemented and amended by this Supplemental Indenture, is in all respects
hereby adopted, ratified and confirmed, and this Supplemental Indenture shall be
deemed part of the Indenture in the manner and to the extent herein and therein
provided. Every Holder of Notes heretofore or hereafter authenticated and
delivered under the Indenture shall be bound hereby. The provisions of this
Supplemental Indenture shall, subject to the terms hereof, supersede the
provisions of the Indenture to the extent the Indenture is inconsistent
herewith.

         SECTION 6.03. Trust Indenture Act Controls. If any provision of this
Supplemental Indenture limits, qualifies or conflicts with another provision
which is required to be included in this Supplemental Indenture by the TIA, the
required provision shall control. If any provision of this Supplemental
Indenture modifies any TIA provision that may be so modified, such TIA provision
shall be deemed to apply to this Supplemental Indenture as so modified. If any
provision of this Supplemental Indenture excludes any TIA provision that may be
so excluded, such TIA provision shall be excluded from this Supplemental
Indenture.

         SECTION 6.04. Governing Law. THIS SUPPLEMENTAL INDENTURE SHALL BE
GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH, THE LAWS OF THE STATE OF NEW
YORK.

         SECTION 6.05. Counterparts. This Supplemental Indenture may be executed
in any number of counterparts, each of which so executed shall be deemed to be
an original, but all such counterparts shall together constitute but one and the
same instrument.

                                       4
<PAGE>
         SECTION 6.06. Effect of Headings. The Article and Section headings in
this Supplemental Indenture are for convenience only and shall not affect the
construction hereof.

         SECTION 6.07. Severability. In case any one or more of the provisions
in this Supplemental Indenture shall be held invalid, illegal or unenforceable,
in any respect for any reason, the validity, legality and enforceability of any
such provision in every other respect and of the remaining provisions shall not
in any way be affected or impaired thereby, it being intended that all of the
provisions hereof shall be enforceable to the full extent permitted by law.

         SECTION 6.08. Successors. All agreements of the Company in this
Supplemental Indenture shall bind its successors. All agreements of the Trustee
in this Supplemental Indenture shall bind its successors.

         SECTION 6.09. Acceptance by Trustee. Pursuant to Sections 11.2 and 11.6
of the Indenture, the Trustee is directed to accept the amendments to the
Indenture effected by this Supplemental Indenture and to execute the trusts
created by the Indenture as hereby amended, but only upon the terms and
conditions set forth in this Supplemental Indenture and the Indenture. Without
limiting the generality of the foregoing, the Trustee assumes no responsibility
for the correctness of the recitals contained herein, which shall be taken as
the statements of the Company and except as provided in the Indenture, the
Trustee shall not be responsible or accountable in any way whatsoever for or
with respect to the validity or execution or sufficiency of this Supplemental
Indenture or the Solicitation Documents and the Trustee makes no representation
with respect thereto. All rights, protections, privileges, indemnities and
benefits granted or afforded to the Trustee under the TIA or the Indenture shall
be deemed incorporated herein by this reference and shall be deemed applicable
to all actions taken, suffered or omitted by the Trustee under this Supplemental
Indenture.

         SECTION 6.10. Endorsement and Change of Form of Notes. Any Notes
authenticated and delivered after the close of business on the Effective Date in
substitution for Notes then outstanding and all Notes presented or delivered to
the Trustee on and after that date for such purpose shall be stamped, imprinted
or otherwise legended by the Company, with a notation as follows:

         "Effective as of September 22, 2005, the date that the Company shall be
first permitted to redeem the Notes has been extended to March 15, 2013, certain
amendments and waivers to the provisions of Section 6.2(a) have been adopted and
the obligation of the Company to make a Coupon Make-Whole Payment upon the
occurrence of a Cash Take-Over Transaction has been adopted, all as provided in
the First Supplemental Indenture, dated as of , 2005. Reference is hereby made
to said First Supplemental Indenture, copies of which are on file with the
Trustee, for a description of the amendments made therein."

                                       5
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed as of the day and year first above written.

                                WILLBROS GROUP, INC.

                                By:    /s/ Warren L. Williams
                                     -------------------------------------------
                                Name:    Warren L. Williams
                                Title:   Senior Vice President, Chief Financial
                                         Officer and Treasurer

                                JPMORGAN CHASE BANK, N.A., successor to
                                         JPMORGAN CHASE BANK, as Trustee

                                By:    /s/ P. Kelly
                                     -------------------------------------------
                                Name:    P. Kelly
                                Title:   Authorized Signatory

                                       6

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