{"id":12362,"date":"2026-02-05T21:39:34","date_gmt":"2026-02-05T20:39:34","guid":{"rendered":"https:\/\/rodervision.com\/technique-declairage-direct-en-computer-vision\/"},"modified":"2026-05-25T17:41:53","modified_gmt":"2026-05-25T15:41:53","slug":"technique-declairage-direct-en-computer-vision","status":"publish","type":"page","link":"https:\/\/rodervision.com\/fr\/technique-declairage-direct-en-computer-vision\/","title":{"rendered":"Technique d&rsquo;\u00e9clairage direct en computer vision"},"content":{"rendered":"\n<div class=\"wp-block-group is-layout-flow wp-block-group-is-layout-flow\">\n<div class=\"wp-block-columns alignwide is-layout-flex wp-container-core-columns-is-layout-7387b849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:40%\">\n<figure class=\"wp-block-image alignleft size-full coblocks-animate\" data-coblocks-animation=\"fadeIn\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"1000\" height=\"1000\" src=\"https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2025\/04\/configurazione_illuminazione_diretta_angolata.png?resize=1000%2C1000&#038;ssl=1\" alt=\"Illuminateurs LED pour la conception de syst&#xE8;mes de vision en &#xE9;clairage direct\" class=\"wp-image-5003\" style=\"object-fit:cover\" srcset=\"https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2025\/04\/configurazione_illuminazione_diretta_angolata.png?w=1000&amp;ssl=1 1000w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2025\/04\/configurazione_illuminazione_diretta_angolata.png?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2025\/04\/configurazione_illuminazione_diretta_angolata.png?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2025\/04\/configurazione_illuminazione_diretta_angolata.png?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2025\/04\/configurazione_illuminazione_diretta_angolata.png?resize=120%2C120&amp;ssl=1 120w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:60%\">\n<h3 class=\"wp-block-heading has-custom-arancio-caldo-color has-text-color has-link-color wp-elements-3eb89647f7b8b0a3aa7235b973156cec\">Engineering Guide to Direct Illumination Techniques in Computer Vision for Surface Inspection and Feature Extraction.<\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Explore the technical complexities of direct illumination in computer vision. This guide covers brightfield, darkfield, coaxial, and dome lighting strategies. Learn how to manage specular reflection, utilize polarization, and optimize wavelength selection to enhance surface defects, textures, and features for reliable industrial quality control and high-speed automated inspection.<\/p>\n<\/div>\n<\/div>\n<\/div>\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-7387b849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:30%\">\n<figure class=\"wp-block-image size-large is-resized has-custom-border has-lightbox\"><a href=\"https:\/\/rodervision.com\/fr\/products\/led-bar-illuminators\/illuminateurs-matriciels-a-led-serie-dl1\/\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"1024\" src=\"https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1.png?resize=1024%2C1024&#038;ssl=1\" alt=\"\" class=\"wp-image-4037\" style=\"border-width:1px;object-fit:contain;width:300px;height:300px\" srcset=\"https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1.png?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1.png?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1.png?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1.png?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1.png?resize=120%2C120&amp;ssl=1 120w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1.png?w=1200&amp;ssl=1 1200w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/><\/a><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:70%\">\n<h3 class=\"wp-block-heading\"><a href=\"https:\/\/rodervision.com\/fr\/products\/led-bar-illuminators\/illuminateurs-matriciels-a-led-serie-dl1\/\">S\u00e9rie DL1<\/a><\/h3>\n\n\n\n<div style=\"height:30px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Profil bas<\/li>\n\n\n\n<li>Design industriel<\/li>\n\n\n\n<li>Technologie HTTM<\/li>\n\n\n\n<li>Driver int\u00e9gr\u00e9 haute stabilit\u00e9<\/li>\n\n\n\n<li>C\u00e2ble avec connecteur M8<\/li>\n\n\n\n<li>Bo\u00eetier en aluminium<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-7387b849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:30%\">\n<figure class=\"wp-block-image size-large is-resized has-custom-border has-lightbox\"><a href=\"https:\/\/rodervision.com\/fr\/products\/led-bar-illuminators\/led-matrix-illuminators-dl2-series\/\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"1024\" src=\"https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL2.png?resize=1024%2C1024&#038;ssl=1\" alt=\"\" class=\"wp-image-4036\" style=\"border-width:1px;object-fit:contain;width:300px;height:300px\" srcset=\"https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL2.png?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL2.png?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL2.png?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL2.png?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL2.png?resize=120%2C120&amp;ssl=1 120w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL2.png?w=1200&amp;ssl=1 1200w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/><\/a><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:70%\">\n<h3 class=\"wp-block-heading\"><a href=\"https:\/\/rodervision.com\/fr\/products\/led-bar-illuminators\/led-matrix-illuminators-dl2-series\/\">S\u00e9rie DL2<\/a><\/h3>\n\n\n\n<div style=\"height:30px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Verre de protection<\/li>\n\n\n\n<li>Design industriel<\/li>\n\n\n\n<li>Technologie HTTM<\/li>\n\n\n\n<li>Driver int\u00e9gr\u00e9 haute stabilit\u00e9<\/li>\n\n\n\n<li>C\u00e2ble avec connecteur M8<\/li>\n\n\n\n<li>Bo\u00eetier en aluminium \u00e0 robustesse \u00e9lev\u00e9e<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n<div class=\"wp-block-columns is-layout-flex wp-container-core-columns-is-layout-7387b849 wp-block-columns-is-layout-flex\">\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:30%\">\n<figure class=\"wp-block-image size-large is-resized has-custom-border has-lightbox\"><a href=\"https:\/\/rodervision.com\/fr\/products\/led-bar-illuminators\/led-illuminators-for-line-cameras-dl1l-series\/\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"1024\" src=\"https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1L.png?resize=1024%2C1024&#038;ssl=1\" alt=\"\" class=\"wp-image-4038\" style=\"border-width:1px;object-fit:cover;width:300px;height:300px\" srcset=\"https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1L.png?resize=1024%2C1024&amp;ssl=1 1024w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1L.png?resize=300%2C300&amp;ssl=1 300w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1L.png?resize=150%2C150&amp;ssl=1 150w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1L.png?resize=768%2C768&amp;ssl=1 768w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1L.png?resize=120%2C120&amp;ssl=1 120w, https:\/\/i0.wp.com\/rodervision.com\/wp-content\/uploads\/2024\/12\/home_focus_banner_DL1L.png?w=1200&amp;ssl=1 1200w\" sizes=\"auto, (max-width: 1000px) 100vw, 1000px\" \/><\/a><\/figure>\n<\/div>\n\n\n\n<div class=\"wp-block-column is-layout-flow wp-block-column-is-layout-flow\" style=\"flex-basis:70%\">\n<h3 class=\"wp-block-heading\"><a href=\"https:\/\/rodervision.com\/fr\/products\/led-bar-illuminators\/led-illuminators-for-line-cameras-dl1l-series\/\">Serie DL1L<\/a><\/h3>\n\n\n\n<div style=\"height:30px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Longueurs jusqu&rsquo;\u00e0 3000 mm<\/li>\n\n\n\n<li>Design industriel avec barre de fixation int\u00e9gr\u00e9e<\/li>\n\n\n\n<li>Technologie HTTM<\/li>\n\n\n\n<li>Driver int\u00e9gr\u00e9 haute stabilit\u00e9<\/li>\n\n\n\n<li>C\u00e2ble avec connecteur M8<\/li>\n\n\n\n<li>Bo\u00eetier en aluminium<\/li>\n<\/ul>\n<\/div>\n<\/div>\n\n<div style=\"height:100px\" aria-hidden=\"true\" class=\"wp-block-spacer\"><\/div>\n\n<p class=\"wp-block-paragraph\">In the field of industrial automation, if backlighting is the tool for shape, <strong>direct illumination<\/strong> is the tool for detail. While backlighting creates a binary world of silhouettes, direct illumination (episcopic lighting) opens the door to the complex reality of surface textures, colors, topography, and material properties.<\/p>\n\n<p class=\"wp-block-paragraph\">For the vision engineer, direct illumination is the art of controlling how light interacts with a surface to create high-quality contrast. Whether you are identifying a microscopic scratch on a polished metal plate or reading a laser-etched DataMatrix code on a curved plastic component, the geometry and quality of your direct lighting setup will determine the robustness of your deployment.<\/p>\n\n<h2 class=\"wp-block-heading\">The Physics of Surface Interaction<\/h2>\n\n<p class=\"wp-block-paragraph\">Direct illumination relies on the light reflecting off the object and into the camera lens. To master this, one must understand the two primary types of reflection dictated by the surface&rsquo;s micro-geometry.<\/p>\n\n<h3 class=\"wp-block-heading\">Specular vs. Diffuse Reflection<\/h3>\n\n<p class=\"wp-block-paragraph\">When a light ray hits a surface, its behavior is governed by the Law of Reflection.<\/p>\n\n<p class=\"wp-block-paragraph\">$$\\theta_i = \\theta_r$$<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Specular Reflection:<\/strong> Occurs on \u00ab\u00a0mirror-like\u00a0\u00bb surfaces (polished metal, glass, liquids). The light reflects at a single outgoing angle. In computer vision, this often leads to \u00ab\u00a0hot spots\u00a0\u00bb or glare that can blind the sensor.<\/li>\n\n\n\n<li><strong>Diffuse Reflection:<\/strong> Occurs on rough or matte surfaces (paper, unpolished wood, cast iron). The light is scattered in many directions (Lambertian reflection). This is generally easier to image because the object appears consistently bright from multiple viewing angles.<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\">The Inverse Square Law and Cosine Law<\/h3>\n\n<p class=\"wp-block-paragraph\">The intensity of light reaching the object ($E$) is inversely proportional to the square of the distance ($r$) from the source and proportional to the cosine of the angle of incidence ($\\theta$):<\/p>\n\n<p class=\"wp-block-paragraph\">$$E = \\frac{I}{r^2} \\cos \\theta$$<\/p>\n\n<p class=\"wp-block-paragraph\">For a vision professional, this means that even minor changes in the mounting distance or the tilt of a part can lead to significant fluctuations in image brightness, potentially breaking threshold-based inspection algorithms.<\/p>\n\n<h2 class=\"wp-block-heading\">Taxonomy of Direct Illumination Strategies<\/h2>\n\n<p class=\"wp-block-paragraph\">Different surface challenges require different lighting geometries. We can categorize direct illumination into four primary technical strategies.<\/p>\n\n<h3 class=\"wp-block-heading\">A. Brightfield Illumination (Partial)<\/h3>\n\n<p class=\"wp-block-paragraph\">Brightfield is the most common technique. The light source is positioned at a relatively high angle relative to the surface (typically $45^{\\circ}$ to $90^{\\circ}$).<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Mechanism:<\/strong> Light reflects off the surface directly into the lens.<\/li>\n\n\n\n<li><strong>Result:<\/strong> Flat, reflective surfaces appear bright; features that scatter light (like scratches or pits) appear dark.<\/li>\n\n\n\n<li><strong>Best for:<\/strong> General presence detection, color inspection, and non-reflective surfaces.<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\">B. Darkfield Illumination<\/h3>\n\n<p class=\"wp-block-paragraph\">Darkfield lighting involves placing the light source at a very low angle (typically $10^{\\circ}$ to $30^{\\circ}$) relative to the object surface.<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Mechanism:<\/strong> Most light reflects off the flat surface and away from the lens. Only light that hits a raised or recessed feature (topography) is scattered into the camera.<\/li>\n\n\n\n<li><strong>Result:<\/strong> The background remains dark, while surface defects, dust, and textures \u00ab\u00a0glow\u00a0\u00bb brightly.<\/li>\n\n\n\n<li><strong>Best for:<\/strong> Scratch detection on polished surfaces, inspecting embossed text, and identifying contaminants on flat substrates.<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\">C. Coaxial (On-Axis) Illumination<\/h3>\n\n<p class=\"wp-block-paragraph\">Coaxial lighting uses a semi-transparent beam splitter to align the light path perfectly with the optical axis of the lens.<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Mechanism:<\/strong> Light is reflected onto the object from the same direction the camera is looking.<\/li>\n\n\n\n<li><strong>Result:<\/strong> It eliminates shadows and is particularly effective for flat, specular surfaces.<\/li>\n\n\n\n<li><strong>Best for:<\/strong> Semiconductor wafer inspection, PCB fiducial alignment, and reading codes on highly reflective packaging.<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\">D. Diffuse (Dome\/Cloudy Day) Illumination<\/h3>\n\n<p class=\"wp-block-paragraph\">Reflective, curved, or irregular surfaces (like a crushed soda can or a blister pack) create \u00ab\u00a0specular glare\u00a0\u00bb that ruins images. Diffuse illumination uses a dome or a large scattering surface to provide light from all angles ($180^{\\circ}$ hemisphere).<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Mechanism:<\/strong> It mimics a \u00ab\u00a0cloudy day\u00a0\u00bb where light comes from everywhere, eliminating directional shadows and hot spots.<\/li>\n\n\n\n<li><strong>Best for:<\/strong> Highly reflective curved surfaces, metal cylinders, and inspecting objects through transparent but wrinkled overwraps.<\/li>\n<\/ul>\n\n<h2 class=\"wp-block-heading\">Comparison of Lighting Geometries<\/h2>\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><td>Technique<\/td><td><strong>Setup Complexity<\/strong><\/td><td><strong>Best Surface Type<\/strong><\/td><td><strong>Objectif principal<\/strong><\/td><\/tr><\/thead><tbody><tr><td><strong>Illuminateur annulaire<\/strong><\/td><td>Faible<\/td><td>Matte \/ Diffuse<\/td><td>General feature recognition<\/td><\/tr><tr><td><strong>Darkfield<\/strong><\/td><td>Medium<\/td><td>Polished \/ Mirror<\/td><td>Surface defect detection<\/td><\/tr><tr><td><strong>Coaxial<\/strong><\/td><td>\u00c9lev\u00e9<\/td><td>Flat \/ Reflective<\/td><td>Eliminating shadows on shiny parts<\/td><\/tr><tr><td><strong>Dome Light<\/strong><\/td><td>\u00c9lev\u00e9<\/td><td>Curved \/ Specular<\/td><td>Eliminating glare on complex shapes<\/td><\/tr><\/tbody><\/table><\/figure>\n\n<h2 class=\"wp-block-heading\">Choix de la longueur d&rsquo;onde et filtrage optique<\/h2>\n\n<p class=\"wp-block-paragraph\">The color of the light determines how it interacts with the material&rsquo;s molecular structure.<\/p>\n\n<h3 class=\"wp-block-heading\">The Color Wheel Principle<\/h3>\n\n<p class=\"wp-block-paragraph\">In direct illumination, we use the color wheel to enhance or suppress features:<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>To make a feature look bright:<\/strong> Use light of the same color (e.g., Red light on a red part).<\/li>\n\n\n\n<li><strong>To make a feature look dark:<\/strong> Use light of the opposite color (e.g., Green light on a red part).<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\">Infrared (IR) vs. Ultraviolet (UV)<\/h3>\n\n<ul class=\"wp-block-list\">\n<li><strong>Infrared ($850\\text{&#8211;}940\\text{ nm}$):<\/strong> Excellent for reducing \u00ab\u00a0visual noise.\u00a0\u00bb IR can penetrate certain inks and plastics, making it ideal for checking fill levels through colored plastic or ignoring distracting print on a package.<\/li>\n\n\n\n<li><strong>Ultraviolet ($365\\text{&#8211;}395\\text{ nm}$):<\/strong> Used primarily for <strong>Fluorescence Inspection<\/strong>. Many adhesives, oils, and specialized inks glow under UV, allowing the vision system to detect their presence on surfaces where they would otherwise be invisible.<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\">Polarization: The Glare Killer<\/h3>\n\n<p class=\"wp-block-paragraph\">When dealing with extreme specular reflection (like \u00ab\u00a0hot spots\u00a0\u00bb on a wet surface), <strong>Polarization<\/strong> is an essential tool. By placing a linear polarizer on the light source and another (an analyzer) on the lens oriented at $90^{\\circ}$, the vision system can \u00ab\u00a0extinguish\u00a0\u00bb the direct specular reflection while allowing the depolarized scattered light through. This significantly increases the dynamic range of the image.<\/p>\n\n<h2 class=\"wp-block-heading\">Integration and Control<\/h2>\n\n<h3 class=\"wp-block-heading\">Strobe and Pulse Management<\/h3>\n\n<p class=\"wp-block-paragraph\">For high-speed lines, continuous lighting often provides insufficient intensity for short exposure times, leading to motion blur. Professional systems utilize <strong>Strobe Controllers<\/strong> to synchronize the light pulse with the sensor&rsquo;s Global Shutter.<\/p>\n\n<ul class=\"wp-block-list\">\n<li><strong>Overdriving:<\/strong> Pulsing an LED at $10\\text{x}$ its rated current for a few microseconds can provide the intensity needed to \u00ab\u00a0freeze\u00a0\u00bb a part moving at several meters per second.<\/li>\n<\/ul>\n\n<h3 class=\"wp-block-heading\">Mounting and Stability<\/h3>\n\n<p class=\"wp-block-paragraph\">In direct illumination, the angle is everything. A shift of $1^{\\circ}$ in a darkfield setup can be the difference between seeing a defect and seeing nothing. Industrial mounting solutions must be vibration-resistant and provide 3-axis adjustment to maintain the \u00ab\u00a0sweet spot\u00a0\u00bb of the optical path.<\/p>\n\n<h2 class=\"wp-block-heading\">Advanced Software Considerations<\/h2>\n\n<p class=\"wp-block-paragraph\">While direct illumination aims to provide the best raw image, software algorithms must still handle the inherent variability of incident light.<\/p>\n\n<ol start=\"1\" class=\"wp-block-list\">\n<li><strong>Gain Control vs. Exposure:<\/strong> Always prioritize increasing light intensity or exposure time over digital Gain. Gain amplifies the noise along with the signal, reducing the precision of edge-detection algorithms.<\/li>\n\n\n\n<li><strong>Flat-Field Correction (FFC):<\/strong> No light source is perfectly uniform. FFC is a software calibration technique that compensates for the \u00ab\u00a0vignetting\u00a0\u00bb or unevenness of the light source, ensuring that a pixel in the corner has the same response as a pixel in the center.<\/li>\n\n\n\n<li><strong>High Dynamic Range (HDR):<\/strong> In cases where a single image cannot capture both dark details and bright highlights (common in direct lighting), multiple exposures can be combined to create a high-contrast master image.<\/li>\n<\/ol>\n\n<h2 class=\"wp-block-heading\">Conclusion<\/h2>\n\n<p class=\"wp-block-paragraph\">Direct illumination is the most versatile\u2014yet challenging\u2014component of a machine vision system. Success requires a deep understanding of the interplay between light geometry, material properties, and sensor physics. By selecting the correct strategy\u2014whether it be the subtle topography revealed by darkfield or the glare-free uniformity of a dome\u2014engineers can ensure that their computer vision algorithms are fed with the highest quality data possible.<\/p>\n\n<p class=\"wp-block-paragraph\">The goal of professional lighting is simple but profound: <strong>make the \u00ab\u00a0good\u00a0\u00bb parts look obvious and the \u00ab\u00a0bad\u00a0\u00bb parts look impossible to miss.<\/strong><\/p>\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><td><strong>Caract\u00e9ristique<\/strong><\/td><td><strong>R\u00e9tro\u00e9clairage<\/strong><\/td><td><strong>\u00c9clairage direct<\/strong><\/td><td><strong>\u00c9clairage diffus<\/strong><\/td><\/tr><\/thead><tbody><tr><td><strong>Direction de la lumi\u00e8re<\/strong><\/td><td>Derri\u00e8re l&rsquo;objet<\/td><td>Avant\/c\u00f4t\u00e9 de l&rsquo;objet<\/td><td>Omnidirectionnel \/ diffus<\/td><\/tr><tr><td><strong>Objectif principal<\/strong><\/td><td>Silhouette &amp; G\u00e9om\u00e9trie<\/td><td>D\u00e9tails de surface &amp; Couleur<\/td><td>Suppression des reflets et ombres<\/td><\/tr><tr><td><strong>Id\u00e9al pour<\/strong><\/td><td>M\u00e9trologie, inspection de trous<\/td><td>Codes-barres, texture, rayures<\/td><td>Pi\u00e8ces brillantes, courb\u00e9es ou m\u00e9talliques<\/td><\/tr><tr><td><strong>Avantage cl\u00e9<\/strong><\/td><td>Contraste maximal des bords<\/td><td>Extraction de d\u00e9tails fins<\/td><td>\u00c9limine les \u00ab\u00a0hot spots\u00a0\u00bb (reflets)<\/td><\/tr><tr><td><strong>D\u00e9fi principal<\/strong><\/td><td>N\u00e9cessite un acc\u00e8s des 2 c\u00f4t\u00e9s<\/td><td>Gestion des reflets sp\u00e9culaires<\/td><td>Encombrement physique (d\u00f4me) &amp; intensit\u00e9<\/td><\/tr><tr><td><strong>Optique id\u00e9ale<\/strong><\/td><td>Optiques t\u00e9l\u00e9centriques<\/td><td>Optiques standard \/ macro<\/td><td>Optiques standard \/ grand angle<\/td><\/tr><\/tbody><\/table><\/figure>\n","protected":false},"excerpt":{"rendered":"<p>Engineering Guide to Direct Illumination Techniques in Computer Vision for Surface Inspection and Feature Extraction. Explore the technical complexities of direct illumination in computer vision. This guide covers brightfield, darkfield, coaxial, and dome lighting strategies. Learn how to manage specular reflection, utilize polarization, and optimize wavelength selection to enhance surface defects, textures, and features for [&hellip;]<\/p>\n","protected":false},"author":157040980,"featured_media":12363,"parent":0,"menu_order":8,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","footnotes":""},"class_list":["post-12362","page","type-page","status-publish","has-post-thumbnail","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.9 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Direct Illumination in computer vision<\/title>\n<meta name=\"description\" content=\"Direct illumination in computer vision is a very diffuse technique. 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