How to Choose 4 Machine Vision Types: Lens Industrial Camera Infrared Imager All-In-One Guide

In modern industrial automation, machine vision technology has become indispensable. Faced with a wide range of machine vision products including industrial lenses, visible-light industrial cameras, thermal imagers and all-in-one smart cameras, many system integrators, end users and purchasers struggle to select the right solution for their application scenarios. This article systematically sorts out the positioning, features and applicable scenarios of these four product categories to help you make informed purchasing decisions.

Figure 1 Positioning Relationship of Four Major Machine Vision Product Categories

1. Overview of Machine Vision Products

Figure 2 Application of Machine Vision System in Automated Production Lines

Machine vision technology adopts optical imaging, image processing, computer vision and other technologies. It acquires image information of measured objects to realize inspection, recognition, analysis and measurement. Its basic principle is to capture object images via imaging equipment, extract valid information through image processing algorithms, and then recognize and process the targets. Machine vision is widely used in industrial automation, intelligent transportation, power inspection, medical care, agriculture and many other fields.

Classified by product form and photosensitive wavelength band, machine vision products mainly fall into four categories as follows: (1) Industrial Lens An industrial lens serves as the "front end of the eye" in a machine vision system. Its core function is to converge light from the measured workpiece onto the image sensor. It cannot generate images independently and must work with a camera. Lenses with high resolution and low distortion deliver clearer and more stable images. Mainstream high-resolution industrial lenses can reach up to 19.2MP, with focal lengths ranging from 2.8mm to 100mm, suitable for high-speed object inspection and precision measurement.

(2) Visible-Light Industrial Camera Visible-light industrial cameras use CMOS or CCD image sensors and operate within the 400–700nm visible light band. They are the most popular imaging devices in the machine vision industry. They normally integrate image sensors, data acquisition circuits and transmission interfaces (GigE, USB3.0, Camera Link, etc.) to output digital images in real time. Typical high-performance visible-light industrial cameras feature resolutions from 1.3MP to 25MP and frame rates of 60–100fps, ideal for high-speed assembly, appearance inspection and dimensional measurement.

(3) Thermal Imager A thermal imager is a special imaging device working in the long-wave infrared (8–14μm) or mid-wave infrared (3–5μm) band. Its core component is an uncooled infrared detector (e.g. vanadium oxide microbolometer). It does not rely on ambient illumination; instead, it images by receiving infrared radiation emitted by objects. Therefore, it can work in total darkness and directly obtain the surface temperature distribution of targets. Mainstream thermal imagers generally have a temperature measurement range of -20℃ to +550℃, temperature accuracy up to ±2℃, and NETD (Noise Equivalent Temperature Difference) below 50mK. They are widely used for power inspection, building energy efficiency testing, industrial high-temperature monitoring and fire early warning.

(4) All-In-One Smart Camera An all-in-one smart camera is a complete system integrating a camera, image processing unit, controller, light source and embedded algorithms inside one housing. Users only need to connect power and network to run it. No separate industrial PC or customized vision software development is required, greatly simplifying system deployment. Typical compact all-in-one units measure approximately 500mm×300mm×100mm and weigh around 5kg, fitting space-limited scenarios requiring rapid deployment. Depending on the photosensitive band, these units can be built based on visible-light modules or infrared modules.

Machine vision products play a vital role in industrial automation, boosting production efficiency, cutting labor costs and improving product quality. For instance, visible-light industrial cameras inspect and sort electronic components in electronics manufacturing; visible-light all-in-one cameras carry out food quality inspection in the food industry; thermal imagers detect overheating risks on power equipment without power outage; infrared thermal imaging assists auxiliary diagnosis in medical applications.

With continuous technological advancement, machine vision products are evolving toward higher resolution, faster frame rates, smaller form factors and greater intelligence. In the future, machine vision will be adopted in more industries and bring more convenience to society.

The industrial lens is the core optical component of a machine vision system, operating based on geometric optics. Focal length and resolution are its two most critical parameters. For mainstream industrial lenses, focal lengths range from 2.8mm to 100mm with resolution above 5MP. In precision measurement applications, high-resolution lenses capture tiny details such as solder joint inspection on circuit boards. Focal length selection depends on use cases: telephoto lenses are for long-distance observation, while wide-angle lenses capture large field-of-view scenes.

As the core photosensitive component of machine vision systems, visible-light industrial cameras are evaluated by imaging quality, size, interfaces and other parameters. A typical high-performance visible-light industrial camera delivers excellent imaging, with 1.3MP resolution and frame rate up to 60fps, capable of capturing fast-moving targets. In addition, it features compact dimensions and abundant interfaces for easy connection with lenses, light sources and industrial PCs. On automated assembly lines, such cameras accurately record the assembly process of small components.

Figure 3 Visible-Light Industrial Camera Capturing High-Speed Moving Objects on Production Lines

Alongside visible-light industrial cameras, thermal imagers represent another independent imaging category, differing only in the photosensitive wavelength band. They use vanadium oxide or amorphous silicon microbolometers as detectors and form images by receiving infrared radiation naturally emitted from objects. This brings three unique advantages. First, they do not rely on ambient light at all and can operate in dark, smoky and dusty conditions. Second, they output temperature field data directly, accomplishing both imaging and temperature measurement simultaneously. Third, they can detect thermal defects invisible to visible light, such as internal equipment overheating and damaged thermal insulation layers. Mainstream thermal imagers offer a temperature measurement range of -40℃ to +550℃ with accuracy up to ±1℃. In the steel manufacturing industry, they are used to inspect surface defects on steel billets; in the power sector, they perform overheat inspection for switchgears and busbar joints.

Figure 4 Thermal Image of Power Distribution Cabinet Captured by Thermal Imager (Pseudo-color Temperature Field Illustration, Orange-red Areas Indicate Overheated Joints)

An all-in-one smart camera is a machine vision system integrating lens, photosensitive unit, image processing module, light source and algorithm controller within a single housing. Its greatest advantage is plug-and-play. Users do not need to separately select and debug lenses, light sources or industrial PCs. High-end inspection all-in-one cameras feature high integration and comprehensive functions for diverse industrial inspection scenarios. Compact all-in-one models have small dimensions and flexible interfaces, ideal for production lines with limited installation space. Economy all-in-one units fulfill basic inspection requirements while keeping costs under control.

In summary, industrial lenses, visible-light industrial cameras, thermal imagers and all-in-one smart cameras each have distinct characteristics for different application scenarios. Proper machine vision product selection requires comprehensive evaluation based on specific application requirements.

Requirements vary greatly across different use cases when choosing machine vision equipment. We recommend a decision-making logic: wavelength band first, then product form. First, confirm whether visible light or infrared is required — infrared for temperature measurement, nighttime operation or smoke penetration; visible light for appearance, dimension and color inspection. Next, decide between a split system (flexible combination) or all-in-one unit (fast deployment).

Key factors for lens selection include resolution, focal length, sensor target size and aperture. For example, high-resolution industrial lenses support 19.2MP imaging. Paired with large-target sensors, they fit scenarios demanding high resolution such as precision inspection on high-speed assembly lines.

Priority parameters for visible-light industrial cameras are resolution, frame rate, interface type and environmental resistance. Compact visible-light cameras feature small form factors and multiple interfaces including GigE / USB3, suitable for space-constrained production lines requiring multi-camera networking.

When selecting thermal imagers, focus on detector resolution (e.g. 384×288, 640×512), temperature measurement range, NETD and frame rate. High-precision thermal imagers deliver superior measurement accuracy and thermal stability, suited for applications requiring quantitative temperature data: power inspection, steel billet temperature testing and building energy efficiency assessment.

All-in-one smart cameras integrate lenses, light sources and controllers to enable fast deployment. High-precision models are used for high-accuracy electronic component inspection. High-stability versions serve food, pharmaceutical and other production lines requiring long continuous operation. Economy all-in-one cameras are suitable for budget-sensitive projects with simple inspection tasks.

Figure 5 Efficiency Comparison of Four Types of Machine Vision Products (Schematic)

In practical applications, performance comparison of products carries great importance. For example, for appearance inspection of auto parts, the all-in-one visible-light solution delivers high resolution and fast processing capacity to effectively boost inspection efficiency. For food industry inspection, highly stable visible-light all-in-one cameras are favored by users for their reliability and easy maintenance. In the textile industry, low-light performance of high-frame-rate visible-light cameras greatly improves inspection results. For power inspection and high-temperature industrial monitoring, thermal imagers are irreplaceable by other equipment. These cases show that selecting the right product category for specific scenarios can greatly improve production efficiency and product quality.

To sum up, when selecting machine vision products, first distinguish by wavelength band (visible light / infrared), then by product form (split / all-in-one). Parameters including resolution, frame rate, dimension, interface type, temperature measurement range, accuracy and NETD should be evaluated comprehensively. By comparing performance and pricing of different products, users can obtain the most cost-effective solution.

Machine vision technology is encountering unprecedented development opportunities. With continuous improvement of parameters such as resolution, frame rate and temperature measurement range, all types of products are evolving rapidly.

Visible-light industrial cameras are developing toward ultra-high resolution (above 65MP), ultra-high speed (tens of thousands of frames per second) and intelligent sensing (on-chip preprocessing). Supporting lenses keep advancing in large target size, low distortion and telecentric design.

The detector is the core of a thermal imager. Mid-to-high-end mainstream thermal imagers support detector resolutions of 384×288, 640×512 and even 1280×1024, with frame rates up to 60Hz, temperature measurement range from -20℃ to +550℃, and NETD below 30mK. New-generation thermal imagers adopt advanced optical materials and readout circuits, achieving long service life and low power consumption while maintaining high resolution.

All-in-one cameras are advancing rapidly in embedded AI algorithms, multi-sensor fusion (visible light + infrared) and cloud-edge collaboration. Inspection tasks that once required development by professional vision engineers can now be completed with simple configuration.

Judging from global and domestic market trends, the machine vision market keeps expanding. Statistics show that the global machine vision market is expected to maintain an annual growth rate of over 10% in the coming years. China’s machine vision market is also growing rapidly, backed by policy support and industrial upgrading.

Looking ahead, machine vision products will feature higher performance, lower cost and wider application. With deep integration of artificial intelligence and big data, machine vision will play a key role in more fields and provide strong technical support for smart manufacturing and industrial upgrading in China.

With continuous technological progress, machine vision products will become smarter and more efficient. When purchasing machine vision equipment, follow the principle of wavelength band first, then product form, and make comprehensive decisions combining actual requirements, budget and future trends. This article provides a systematic category comparison analysis to help readers avoid detours during product selection.