Define the defects, with samples

List every defect class you need to detect and provide physical samples. A requirement such as "detect all cosmetic defects" cannot be tested.

Build a challenge set

Agree a set of known-defective and known-good samples, with the number per class. Acceptance is then measurable: for example, ≥ 98.0 % detection per class and a maximum false-reject rate on good product.

Separate requirements from solutions

The specification should state what must be detected, at what rate and with what records — not which camera to use. That leaves room for a feasibility study.

Records and data integrity

State which records are required (batch reports, images of rejects, audit trail) and who may change settings. These requirements drive the software design.

Responsibilities

Be explicit about who does what: the integrator provides specifications, tested equipment and test documentation; the manufacturer performs qualification and release according to its own quality system.