Your food manufacturing business relies on inspection and quality control systems to ensure every product that leaves your facility meets your quality standards. Vision inspection systems take images of your products to look for discrepancies and defects. But what’s the difference between 1D, 2D, and 3D vision inspection systems, and which is right for your product line?
You may think that 3D imaging is best simply because it provides the most detail, but this may not be the case. Learn the features, benefits, and downsides of each of these systems to make an informed decision for your QA process.
Understanding the Basics
Before you can know the difference between 1D, 2D, and 3D vision inspection systems, you should understand the basics of each. As you might expect, the main differences have to do with the type of images they take.
- 1D vision systems scan only one line at a time. They use a laser sensor to scan an item as it moves down a conveyor belt. Stitching together the line images forms a cohesive 2D picture.
- 2D vision systems take full, flat images of the object. They capture the object’s length and width but not its height.
- 3D vision systems use multiple cameras to compile a three-dimensional image of an object. The object can be rotated around an axis within the digitized model, allowing you to inspect it from every angle and pinpoint minuscule defects at the manufacturing stage.
Most vision inspection systems store their images in a computer, allowing your workers to reference past images. Some systems automatically identify specific data points with each scan; for example, 3D systems can identify an object’s thickness, volume, and height while detecting angles, curves, and holes for accurate comparisons.
Capabilities and Applications
Just because 3D vision systems show the most detail does not necessarily mean they are right for your company. Understanding each system’s capabilities and recommended applications can help you determine which would suit your QA process without overspending on unnecessary features.
1D Vision Systems
If you only need to conduct surface inspections of products that move along a conveyor belt, 1D vision systems should suit your needs.
Because 1D vision systems stitch together the line images they collect, you can use them similarly to 2D vision systems. You’ll be left with a two-dimensional image of the entire item. However, these systems offer one major advantage over 2D systems: they don’t blur.
Whereas you would have to temporarily halt the conveyor belt to take a 2D image of a food item, a 1D vision system keeps items moving down the line.
Applications of 1D vision systems include:
- Inspecting items in continuous motion on a conveyor belt
- “Unwrapping” cylindrical objects like cans and bottles
- Scanning barcodes
However, the scans these systems take are not quite as detailed or precise as other systems.
2D Vision Systems
A 2D vision system may be ideal if you need to visually inspect items that are not moving on a conveyor, such as if your manufacturing process instead uses pick-and-place machines. These cameras take photos of the item from one angle, typically the top. As a result, they usually do not provide depth information but instead look for visual defects.
You can choose between black-and-white or color 2D cameras. Color cameras take more detailed scans but have longer processing times. Either option can help you identify high-contrast differences in a product’s texture or color.
These systems are commonly used in the automotive industry to confirm the position and location of features, verify labels, and look for scratches in polish. However, they cannot take depth scans, have limited light sensitivity, and can’t always identify low-contrast variations.
3D Vision Systems
Your company may opt for 3D vision inspection systems if you need to verify an object’s depth, precise location in space, volume, and surface angles. These systems use multiple cameras or lasers to create a 3D digitized model of each product on your line.
These vision systems can measure and detect a range of features, such as:
- Thickness
- Height
- Angles
- Curves
- Surface and assembly defects
- Volume
- Shape
- Holes
They can also guide robots in assembly lines by verifying the position of an item.
Because of their detailed capabilities, 3D vision inspection systems are necessary for critical industries like aerospace, precision engineering, and automotive manufacturing. However, 3D inspection systems are more expensive and complicated to install and require more maintenance than simpler 1D and 2D systems.
Data Acquisition and Processing
Understanding the difference between 1D, 2D, and 3D vision inspection systems also involves knowing how each system collects and processes data.
How Data Is Collected in Each System
One-dimensional vision inspection systems use laser triangulation to take measurements of products. They throw a laser point at the object, reflecting the laser back to the sensor on the scanner. The laser gathers line images that your system can stitch into 2D images.
Two-dimensional and three-dimensional cameras also take advantage of laser triangulation to create comprehensive images from basic scans. While 2D systems use one camera to capture a single image, 3D systems utilize several cameras to capture images from all angles. These machines use structured light imaging to extract three-dimensional shapes.
Image Processing Techniques Used in Each System
Vision inspection systems use image processing software to analyze the images taken by their lasers or cameras. The software uses algorithms to analyze the pixel patterns, contrasting colors, and other visual details based on the system’s capabilities.
- 1D vision systems combine the images a laser takes into one 2D image. Some systems create distinct images for each object, while others create an “infinite width image” that continually compiles all line images.
- 2D vision systems capture and process a two-dimensional map with an X and Y axis, then compare variations in intensity for defect detection.
- 3D vision systems use software that compiles the images taken from various angles into one 3D model of the object. The software records precise measurements of the item based on this model.
Accuracy, Precision, and Cost
These three vision inspection systems vary in precision, accuracy, and cost. Consider these differences before determining the right system for your company.
Factors Affecting Accuracy and Precision
Many factors can impact the accuracy and precision of a vision inspection system:
- The type of image it takes (laser imagery vs. camera imagery)
- The image capture speed
- Whether the item is in motion or still
- The lighting in the manufacturing facility
- The saturation of the image (color vs. black and white)
- The quality of the lens
- The number of pixels captured in the image
- The working distance
- The field of view
Comparing Performance Metrics
Choosing a high-quality vision inspection system means capturing precise and accurate photos, whether in 1D, 2D, or 3D. However, these systems have different performance capabilities, so you should choose the one that best meets your needs for accuracy and precise measurements.
One-dimensional systems analyze an image line by line, offering precise yet simple analysis. Two-dimensional systems that take black-and-white images may be less precise than ones that take color images due to the differences in contrast between the two. Meanwhile, 3D systems offer the most accuracy and precision, capturing high-detailed, comprehensive images showing the entire item.
Cost Considerations for Each System and ROI
Cost is another significant difference between 1D, 2D, and 3D vision inspection systems. The more features and capabilities they include, the higher their price will be.
If your business depends on producing items that meet extreme criteria for precision, a 3D vision inspection system could provide a worthwhile ROI. Consider this system if even a few millimeters difference in depth or size could be expensive to resolve if left undetected.
Meanwhile, 1D and 2D inspection systems have similar capabilities, though 1D systems are more affordable. If your items move on a conveyor belt, a 1D system could meet your needs and save you money.
Integrations and Considerations
Finally, consider the following before choosing a vision inspection system.
Integration With Other Systems
Your new vision inspection system should integrate flawlessly with your other machinery. If you use a moving conveyor belt, you may opt for a 1D system. If the lighting in your facility is dim, you may need a 3D system to capture low-contrast differences adequately.
Compatibility and Ease of Use
You should choose a vision inspection system that is compatible with your workflow and won’t require much downtime. If operators constantly need to troubleshoot problems or fix bugs, your production time will suffer.
Operator Training Requirements
Operators must be trained on your new vision inspection system, but complex systems require more intensive training. Consider this when planning to adopt your new system.
Contact TDI Packsys Today
Now that you know the difference between 1D, 2D, and 3D vision inspection systems, are you looking for high-performance systems for food production? Our line of vision systems at TDI Packsys features top-tier artificial vision equipment for 100% quality control and object recognition. Contact us today at 877-834-6750 to learn more.
