Factors to Look for When Choosing The Right Industrial Cameras Lens
As a critical component of the machine vision system, the industrial camera is usually installed on the machine assembly line to replace human eyes to do measurement and judgment. Thus, choosing the right camera lens is also an essential part of machine vision system design. How should we choose the right industrial camera lens? What problems should be paid attention to when choosing an industrial camera lens? Let’s learn about it.
Basic Consideration Regarding Choosing Industrial Cameras Lens
Choosing CCD or CMOS camera according to different applications
The CCD industrial cameras lens is mainly used in the image extraction of moving objects. Of course, with CMOS technology development, the CMOS industrial camera is also applied for many chip mounters. The CCD industrial camera is widely used in vision automatic inspection. CMOS industrial cameras are widely used because of their low cost and low power consumption.
Resolution of industrial cameras lens
Firstly, by considering the object’s accuracy to be observed or measured to select the resolution accordingly. If camera pixel accuracy = single direction field of view size/camera single direction resolution, then the camera’s resolution in one direction = the size of the field of view in one direction / the theoretical accuracy.
If the single field of view is 5mm and the theoretical accuracy is 0.02mm, the single direction resolution is 5 / 0.02 = 250. However, to increase the stability of the system, not only one-pixel unit is used to correspond to one measurement/observation accuracy value. Generally, multiple four or higher can be selected. In this way, the camera needs a single direction resolution of 1000 and 1.3 million pixels.
Secondly, considering an industrial camera’s output, high resolution is helpful for posture observation or machine software analysis and recognition. If it is the VGA or USB output, It should be observed on display; thus, it also depends on the resolution of the display. No matter how high the resolution of an industrial camera lens with industrial vision technology is, it isn’t very meaningful if the resolution of the display is not enough. If you use the memory card or the photo-taking function, the high resolution of an industrial camera also helps.
Camera frame number of industrial cameras lens
When the measured object is moving, the industrial camera lens with high frame number should be selected. But generally speaking, the higher the resolution, the lower the number of frames.
The match of the industrial lens
The size of the sensor chip should be less than or equal to the lens size, and the C or CS-mount should also match.
Additional Considerations over Choosing the Right Camera Lens
C interface or CS interface. The interface distance of the C interface is 17.5mm, while that of the CS interface is 12.5mm. Only the right interface could lead to focus.
Choosing a camera lens should also consider the size of the photosensitive device. For a 2/3-inch photosensitive chip, the industrial cameras lens corresponding to the imaging coil should be selected. If 1/3"or ½" is selected, there will be a large dark angle.
Select the focal length; that is, select the industrial lens whose field of view is slightly larger than the observation range.
Depth of field and light environment should match. For areas with enough light or light source illumination, a small aperture can be chosen to increase the depth of field, thereby improving the shooting clarity. Where there is not enough light, a slightly larger aperture or a sensitive chip with high sensitivity would be selected.
Current Trends over Industrial Cameras Lens Choices
For choosing the right camera lens, here are several popular trends nowadays.
Firstly, image sensors have made great strides in recent years. The trend is to have more and more pixels for better resolution of industrial cameras lens, as well as a greater sensitivity (backlight image sensor).
What’s more, the CCD technology becomes more efficient and now shares more and more features with CMOS technology sensors.
In terms of communication interfaces, they transmit data faster and faster. The trend over the next few years will be to transmit data wirelessly, namely using Wifi.
What is an Industrial Inspection Lens?
https://www.canrilloptics.com/what-is-a-telecentric-lens.html
Industrial lenses are very important imaging components in machine vision systems. For the system to fully perform its functions, industrial lenses must meet the requirements. At the beginning of the 21st century, with the widespread application of machine vision systems in the field of precision inspection, it is difficult for ordinary industrial lenses to meet the inspection requirements. To make up for the shortcomings of ordinary lens applications and meet the needs of precision inspection, telecentric lenses came into being.
Telecentric lens design is based on its unique optical characteristics: high resolution, ultra-wide depth of field, ultra-low distortion, and unique parallel light design, which brings a qualitative leap in precise machine vision inspection.
Ⅰ. Industrial Telecentric Lens Definition
Telecentric lens is mainly designed to correct the parallax of the traditional industry lens. It can be within a certain object distance range so that the image magnification will not change, which is suitable for the situation where the measured object is not on the same object surface. It is a very important application. Telecentric lenses have always been favored by machine vision applications that require high lens distortion due to their unique parallel optical path design.
Industry Lens
Ⅱ. Types of Industry Inspection Lens
Generally, the industry lens with industrial vision technology consists of FA lens, Zoom lens and telecentric lens. When the inspected object has serval surfaces or has angles with lens, or the object is moved up and down, or requires high precision and low distortion, the telecentric lens will be required.
Ⅲ. Application Advantages Of Industrial Inspection Lens
The telecentric industry lens of the telecentric optical system is mainly used for precision measurement. In the precision optical measurement system, due to the ordinary optical lens, there will be certain constraints, such as image distortion, errors caused by the choice of viewing angle, and boundary uncertainty caused by improper light source interference, which will affect the accuracy of measurement. The industrial inspection telecentric lens can effectively reduce or even eliminate the above-mentioned problems. Therefore, the industrial inspection lens has become a decisive component of a precision optical measurement system, and its application fields are becoming more and more extensive.
What Are the Classifications of Telecentric Lenses?
https://www.canrilloptics.com/what-are-the-classifications-of-telecentric-lenses.html
Ⅰ. The classifications of a telecentric lens
The telecentric lens types are mainly divided into the object-space telecentric lens, image-space telecentric lens and bi-telecentric lens.
Ⅱ. Introduction of different telecentric lens types
1. Object space telecentric lens
The object space telecentric lens places the aperture diaphragm on the image space focal plane of the optical system. When the aperture diaphragm is placed on the image-side focal plane, even if the object distance changes, the image distance also changes, but the image height does not change. There is no change, that is, the measured object size will not change. Object space telecentric lenses are used for industrial precision measurement, with minimal distortion, and high performance can achieve no distortion.
2. Image-space telecentric lens
The image space telecentric lens, by placing an aperture stop on the object focal plane, makes the chief ray of the image side parallel to the optical axis so that although the installation position of the CCD chip is changed, the projected image size on the CCD chip remains unchanged.
3. Bi-telecentric lens
The bi-telecentric lens combines the advantages of the above two telecentric lenses. In industrial image processing, generally, only object space telecentric industrial lenses are used. Sometimes there are telecentric lenses on both sides (of course the price is higher). In the field of industrial image processing/machine vision, the image space telecentric lens generally does not work, so this industry basically does not use it.
Stumbled upon this #computerVision imaging resource guide by #EdmundOptics - full of really useful information when choosing the t ypes of light sources and cameras to use for your computer vision systems. I have never considered the physics level of this before for computer vision, but it can actually make your software life much easier to find edges and such for objects you are scanning. Worth a read! The video below is a little taster of what you can learn which covers #telecentric illumination which produces way clearer edges on the image received. https://www.edmundoptics.com/resources/industry-expertise/imaging-optics/imaging-resource-guide/