In precision optical measurement, I have worked in the industry for over twenty years, and I understand how critical lighting conditions are for video measuring machines (VMMs). A VMM captures images of workpieces and extracts size and shape information to achieve precise measurement. However, even high-precision optical systems can produce measurement errors if lighting is poorly designed.

The grayscale values captured by the camera directly reflect the workpiece surface brightness. Low light increases image noise, potentially obscuring edges, while excessive light may cause saturation, losing edge details. More importantly, uneven lighting creates local highlights or shadows, affecting edge detection and causing misidentification or missed edges.

In early projects, uneven lighting often led to unstable edge detection. For example, when measuring a batch of plastic gears, slight reflections on the gear tops were mistakenly identified as edges, while the valleys remained unclear, resulting in measurements deviating over 0.02 mm. In precision mechanical parts, such deviations can directly affect assembly quality. Years of experience have shown me that this issue is not only related to optical precision but also closely tied to lighting layout.

To improve measurement stability, I recommend using uniform and controllable lighting, such as ring LED backlights, coaxial illumination, or oblique lighting combinations. For transparent or semi-transparent workpieces, diffuse or dual lighting can reduce glare and shadows. Properly adjusting the light angle and intensity significantly enhances image clarity and edge recognition reliability.

In addition, brightness adjustments are essential. Grayscale balancing and background compensation can stabilize local brightness differences, mitigating the effects of uneven lighting. In electronic component measurement, I have found these methods provide reliable results even under variable lighting.

Material properties also affect lighting influence. Smooth, reflective, or transparent surfaces are prone to glare, while textured surfaces may produce shadows. Combining optical design, lighting schemes, and material characteristics is key to maintaining measurement accuracy. For instance, in glass lens profile measurement, adding coaxial light and adjusting angles can effectively reduce lighting-induced interference.

In summary, lighting intensity and uniformity are critical to optical measurement accuracy. With over twenty years of experience in the field, I believe achieving stable and precise results in complex conditions requires careful lighting design, brightness adjustment, and consideration of workpiece materials. Coordinating these factors ensures reliable and consistent measurements.