What type of lighting is used in machine vision?

Types of Lighting Used in Machine Vision

Machine vision systems rely heavily on precise lighting to enhance the features of the object being inspected, allowing cameras and algorithms to capture and process images with high fidelity. The choice of lighting can significantly impact the system's performance. Here are the primary types of lighting used in machine vision:

1. Bright Field Lighting

Bright field lighting is used for objects that need illumination from the same angle as the camera, creating a bright image of the object. It is ideal for inspecting shiny or reflective components.

2. Dark Field Lighting

Dark field lighting illuminates the object at a shallow angle, highlighting surface irregularities and defects such as scratches or dents. This technique is perfect for detecting surface features that are not visible under normal lighting conditions.

3. Backlighting

Backlighting illuminates the object from behind, creating a silhouette. This is particularly useful for measuring dimensions, detecting edges, and inspecting the shape or outline of objects.

4. Structured Lighting

Structured lighting involves projecting a pattern of light (such as lines, grids, or dots) onto the object. The deformation of this pattern on the object is then analyzed to determine its 3D shape or to enhance texture details. This method is highly effective for 3D imaging and surface topography studies.

5. Diffuse Lighting

Diffuse lighting provides even, omnidirectional light, reducing shadows and reflections. It is often used in combination with other lighting techniques to achieve a uniform illumination across the object's surface, ideal for inspecting objects with irregular surfaces or complex geometries.

6. Coaxial Lighting

Coaxial lighting illuminates the object through the same optical path as the camera lens. This method is useful for examining flat or highly reflective surfaces, as it minimizes shadows and reflections.

7. Strobed Lighting

Strobed lighting uses short, intense bursts of light to freeze motion for high-speed imaging. This technique is essential in applications where the objects are moving rapidly, such as on production lines.

8. Multi-Spectral and Hyperspectral Lighting

Multi-spectral and hyperspectral lighting involve illuminating the object with various wavelengths of light, either sequentially or simultaneously. This approach is used to gather information beyond what is visible to the naked eye, such as material composition or verifying the presence of specific features.

Each type of lighting serves a specific purpose in machine vision systems, and the choice of lighting depends on the application requirements, including the object's material, shape, and the details being inspected. Engineers and designers often employ a combination of these lighting techniques to optimize the machine vision system's accuracy and efficiency.