Lighting is a critical factor for machine vision inspections. From selecting the best lighting options to configuring them in the most optimal setups, customizing lighting for your applications can help produce better results. Unlike everyday smartphone photography, which is optimized for the human eye, machine vision uses lighting to optimize how objects appear to the camera's sensors. The most successful machine vision applications use lighting that highlights features of interest while minimizing visual noise.
Why lighting matters for Machine Vision
At a basic level, cameras contain sensors that capture incoming light as images. While most photos are typically captured for human review, machine vision applications look at images differently, and they typically perform best on high-contrast images. The central goals of lighting are to highlight features of interest and reduce the focus on the rest of the image.
Two main considerations factor into lighting decisions:
Setup environment — There is an ideal lighting solution for any environment. Space constraints, levels of ambient lighting, support structures, conveyor speed, and other variables in the immediate inspection area influence what lighting products and configurations should be used.
Object factors — Shape, material, size, color, reflectivity, inspection elements, and other characteristics of the object inform decisions around lighting options.
All Samsara cameras feature built-in LEDs, and four additional standalone lighting options are available for even greater flexibility. Here are the types of lights we offer:
Built-in light- Twenty embedded LEDs on the VS2 cameras provide direct, high-contrast lighting. The brightness is easily adjustable through the Samsara dashboard. Bar light - A versatile option that provides uniform lighting along a strip. Typically used to provide directional lighting. Ring light - A bright circular light typically used to provide directional lighting. Dome light - A hemisphere of light that provides soft illumination. Typically used to surround an object with uniform lighting. Area light - A large rectangular light typically used for backlighting or directional lighting.
Below, we show you how each light can be used as well as common lighting arrangements.
Bright Field Lighting - One of the most common configurations, bright field lighting provides direct lighting onto an object, offering high contrast illumination.
Best for: reading text & barcodes on matte objects, label verification
Compatible Samsara lights: built-in, bar, ring, area
Dark Field Lighting - Dark field lighting illuminates objects at shallow angles to accentuate edges, combat glare, or highlight surface features.
Best for: defining edges & shapes, highlighting surface features, finding defects on shiny objects
Compatible Samsara lights: bar, area, ring
Backlighting - Uniform lighting placed behind objects of interest allow silhouettes, text, barcodes, and other features to achieve high contrast from transparent or translucent materials.
Best for: fill level inspection, label verification on transparent objects
Compatible Samsara lights: area
Dome Lighting - Dome lights offer soft, diffuse lighting that eliminates shadows and glare.
Best For: finding defects & reading labels on small reflective objects
Compatible Samsara lights: dome
Ring Lighting: - Circular lighting reduces shadows by providing illumination from multiple angles. Ring lights offer versatility by offering either bright field lighting at longer distances or dark field lighting at shorter distances.