7 Key Points for Industrial Lens Selection-Telecentric Optics helps you choose lenses

7 Key Points for Selecting Industrial Lenses - Terahertz Optics Helps You Choose Lenses

As one of the core components of a machine vision system, the suitability of industrial lens selection has a great impact on image acquisition. Based on many years of experience in industrial lenses and telecentric lenses, Terahertz Optics (BTOS) offers the following selection process.

1. Analyze Customer Needs (From the Customer's Perspective)

Sales and technical engineers analyze the scenarios based on customer feedback, such as the working environment for the lens, whether there are other components between the lens and the object (like lenses or glass), etc., aiming for customization.

Following customer consultation, the analysis often includes the following points:

1. Space and Size: Consider the physical length of the industrial lens and other parameters.
2. System Movement: Determine if the system operates in a mobile or stationary context.
3. Spectral Requirements: Assess special spectral response requirements; for UV environments, standard glass lenses might attract ultraviolet light.
4. Cost Considerations: Evaluate budgetary constraints.
5. Lighting Needs: Decide whether additional light sources are necessary (for brightness, localized lighting, etc.).
6. Industrial Camera Conditions: Assess environmental factors like temperature resistance and humidity.
7. Additional Components: Determine if other hardware is needed.

2. Determine the Need for Telecentric Lenses

For precision measurement systems, telecentric lenses are required. The primary function of telecentric lenses is to counteract perspective differences (caused by varying distances), ensuring consistent magnification within a certain range. Usually, telecentric lenses have fixed focal lengths and working distances. Some telecentric lenses are large, with weights exceeding 10 kg, requiring careful consideration of field of view, working distance, space limitations, and motion control before selecting the lens model and specifications. For standard defect detection or presence checks, use telecentric lenses with low distortion.

3. Depth of Field in Machine Vision Lenses

Certain visual systems require lenses with large depths of field. For example, some inspections need industrial cameras at certain angles while ensuring the entire object is clear. A deep depth of field is also needed when the measured object isn't on a single plane. Factors like shorter focal length, smaller aperture, greater distance from the lens, and larger camera pixels can increase depth of field. A smaller aperture and good lighting simplify focusing, but it may lose fine detail.

4. Machine Vision Lens Sensor Size

Ensure compatibility with the camera's sensor size. The maximum lens size must be greater than the camera's sensor size to avoid distortion.

5. Machine Vision Lens Interface

The camera and lens interface must be compatible, typically using C, CS, or F mounts.

6. Focal Length of Machine Vision Lenses

Focal length significantly affects field of view and working distance. Before determining focal length, consider factors like field of view, working distance, and camera sensor size.

7. Distortion in Machine Vision Lenses

Distortion is caused by uneven magnification in the field of view, leading to image distortion. Due to manufacturing processes, distortion is inevitable. High-quality lenses have lower distortion. In precision measurement systems, consider lens distortion to maintain accuracy.

Why Use Telecentric Lenses for Reducing Inspection Stations

Using telecentric lenses in complex or challenging projects can provide unique advantages, potentially reducing inspection stations, optimizing software, improving inspection efficiency, and lowering costs.