Industrial Vision Systems Application - Industrial Lenses

Industrial Vision Systems Application - Industrial Lenses

Industrial lenses are utilized in automatic inspection, workpiece processing, assembly automation, and production process control and monitoring. The image recognition process in an industrial vision system involves extracting relevant information from raw image data and providing a highly abstracted description of image content to interpret and make judgments about certain elements of the image. Industrial vision systems are designed for specific tasks, simplifying the more complex primary machine vision systems. They are applied across almost every industrial production domain, especially for tasks requiring high speed, precision, or reliability.

General Structure Industrial vision systems are not as sophisticated as laboratory-based machine vision systems. They need to be cost-effective, highly reliable, and fast. Usually, these systems are simplified for known site conditions by, for instance, setting up a specific layout between cameras and lighting, and limiting the number and characteristics of visual objects. Below is a typical industrial vision system structure, consisting of lighting, cameras, image pre-processing, data compression, image storage, and image interpretation. Data from the camera is stored in the computer's memory for data compression and interpretation. The pre-processing stage enhances images and suppresses noise. Since these systems often require fast sequential image interpretation, front-end data compression devices are commonly used.

Lighting The lighting component is critical to the modern vision system's effectiveness. Clear contrast between the target and the background is key. The general lighting layouts are:

1. Backlight: Creates strong contrast, often used in binary image recognition techniques, like sorting items on a conveyor belt.
2. Diffuse Overhead Light: Suitable for recognizing separate parts or objects with unknown surface orientation, like flat items mixed in a box.
3. Direct Overhead Light: Provides stable high-contrast images on stable surfaces, suitable for binary image recognition.
4. Structured Light: Uses laser dots, beams, or grids for three-dimensional measurement, often in laser scanning.

Camera Systems Cameras in industrial vision systems can be cathode ray tube or solid-state type. Line-scan cameras are used for high-precision measurements. Solid-state cameras have advantages in reliability, longevity, and stable imaging, with comparable prices to vacuum tube cameras.

Image Pre-Processing and Compression Image pre-processing involves:

1. Shadow Correction: Smoothes out uneven lighting.
2. Gray-Scale Correction: Linearly or non-linearly transforms input gray values to improve image quality.
3. Noise Filtering: Uses low-pass filters to suppress noise.
4. Image Enhancement: Enhances image contours with high-pass filters.

Data compression in industrial vision systems often involves thresholding gray-scale images to produce binary images. The methods for data compression are typically region-based for binary images and contour-based for gray-scale images.

Image Interpretation Image interpretation describes the content of an image according to a specific task. It relies on image model matching, often using simple template matching for smaller sets of prototypes. Complex tasks may require advanced techniques like search methods or clustering.

Modeling and Applications Flexibility is a key design factor, and fully automated methods are still under development. Industrial vision systems can be applied in various tasks such as target location, defect inspection, sorting, grading, measuring liquid levels, and more. They are categorized into three primary applications:

1. Automatic Inspection: Fast, contactless measurements with near 100% inspection rates.
2. Part Processing and Assembly: Determining part location and orientation, guiding robots in assembly tasks.
3. Production Process Control: Often used in welding control and to read barcode labels for production line operations.

Industrial vision systems are widely used to enhance automation, quality control, and production efficiency in modern manufacturing and industrial processes.