How to choose industrial lenses based on resolution, distortion rate and depth of field?

In the fields of machine vision and automated inspection, industrial lenses, as key components in image acquisition systems, directly impact image quality and system performance. With the continuous expansion of industrial vision applications, accurately selecting industrial lenses based on three key parameters: resolution, distortion rate, and depth of field, has become a focus for many engineers and companies. This article will analyze the key points to consider when selecting industrial lenses, focusing on these three key indicators to help users accurately identify the most suitable lens among a wide range of products.

1. Resolution: Matching the Camera to "See Clearly"

Resolution is a key indicator of lens image clarity. Different visual inspection tasks require different levels of image detail, and high-resolution lenses can effectively reveal more subtle defects or features.

Selection Recommendations:

Matching the Camera Sensor Pixels: For example, if using a 5-megapixel camera, select a lens with a resolution of at least 5MP.

Compatible Target Size: The lens should support an imaging range that matches the camera sensor size to avoid blur or vignetting.

Driven by Inspection Requirements: For high-precision tasks such as micro-component inspection and surface defect identification, lenses with high resolution and high MTF values are preferred.

2. Distortion: Ensuring Imaging Accuracy

Distortion refers to the geometric deviation of an image produced by a lens. Common inspection issues include stretching or compression of edges. For precision measurement or positioning, lens distortion can significantly impact measurement accuracy.

Selection Recommendations:

Low-distortion lenses are preferred: Telecentric lenses, fixed-magnification lenses, and low-distortion FA lenses ensure geometric consistency and are suitable for measurement applications. Distortion tolerance is determined by the application: For defect detection applications other than dimensional measurement, moderate distortion is acceptable, but excessive distortion can lead to inaccurate results.

Correction Assistance: Some software can perform distortion correction, but hardware-level lens selection is more fundamental.

3. Depth of Field: Maintaining Clear Multi-Layer Images

Depth of field determines the range of distances between the front and back of an object while maintaining a clear image. Lens depth of field is particularly important when the surface of the object being measured is not completely flat or has height differences.

Selection Recommendations:

Small aperture, large depth of field: While maintaining brightness, a lens with a smaller aperture can achieve a greater depth of field. Lens Focal Length: Short-focus lenses typically have a greater depth of field and are suitable for close-range inspections; long-focus lenses require more precise focusing.

Consider imaging distance and object height differences: Choose a lens whose depth of field coverage matches the height differences in the actual inspection scene.

Selecting an industrial lens involves more than just comparing individual parameters; it involves optimizing the performance of the entire vision system. A thorough evaluation of resolution, distortion, and depth of field, combined with specific application requirements and equipment configuration, will ultimately lead to the selection of the right lens and improved visual inspection accuracy, stability, and efficiency.

As a professional vision solutions provider, Zhixiang Shijue continues to provide high-performance industrial lenses and customized vision solutions for a variety of industries, including 3C electronics, automotive manufacturing, food packaging, and semiconductors. Contact us for lens selection assistance and product trials.