Stop Focusing Only on “Higher Resolution” — The Wrong Pixel Size Can Compromise Detection Performance

When selecting an industrial camera for machine vision applications, many engineers instinctively assume:

the smaller the pixel size, the higher the precision.

As a result, sensors with 1.6μm or 2.0μm pixels are often immediately perceived as “more advanced.”

However, in real-world projects, the answer is far more nuanced.

Many users invest in ultra-small pixel cameras only to encounter issues such as:

• Dark images

• Increased image noise

• Motion blur in high-speed inspection

• Lens resolution limitations

• Actual detection performance below expectations

In many cases, the root cause is simple:

the pixel size was not selected correctly.

In this article, we will break down how to choose the right industrial camera pixel size from 1.6μm to 10μm, based on real application scenarios.

1. Remember This First: Small Pixels for Detail, Large Pixels for Stability

If we had to summarize the core logic in one sentence, it would be:

Small pixels are better for fine details, while large pixels are better for stable imaging.

Generally, pixel sizes can be divided into three practical ranges:

• 1.6–2.0μm: ultra-high precision

• 2.74–3.45μm: mainstream all-purpose

• 5–10μm: low-light and high-speed applications

Each range serves a completely different purpose.

2. 1.6–2.0μm: Designed for Fine Detail Inspection

This category belongs to ultra-small pixels.

Its biggest advantage is clear:

higher resolution within the same sensor format

For example, on the same sensor size:

• 3.45μm → 12 MP

• 1.6μm → 20 MP or higher

This makes it highly suitable for fine-detail inspection tasks such as:

• Semiconductor wafer inspection

• PCB solder joint inspection

• Micro scratch detection

• OCR / character recognition

• Micron-level dimensional measurement

Applications such as consumer electronics and chip packaging often benefit significantly from this pixel range.

3. But Smaller Pixels Are Not Always Better

This is where many projects run into problems.

Smaller pixels come with trade-offs.

1) Higher Lighting Requirements

The smaller the pixel, the smaller the light-sensitive area.

Under the same exposure time, less light reaches each pixel.

This means:

stronger illumination is required

Otherwise, issues such as the following may appear:

• Dark images

• Higher gain settings

• Increased noise

2) High-Speed Imaging Challenges

In high-speed inspection systems, exposure times are usually extremely short.

For example:

• 20μs

• 50μs

Under such conditions, small pixels may struggle to capture enough light.

This is especially critical in fast production line inspection.

3) Much Higher Lens Requirements

This is one of the most overlooked factors.

The smaller the pixel, the higher the lens resolving power must be.

Otherwise, you may face the classic problem:

high resolution on paper, soft images in reality

In other words:

higher pixel count does not always mean higher precision

4. 2.74–3.45μm: The Golden Range for Machine Vision

If there is one “safe” and versatile range, this is it.

This is currently the most mainstream pixel size range in industrial cameras.

Most machine vision projects eventually fall into this category.

The reason is simple:

it offers the best balance between precision, brightness, and cost

Suitable for most applications, including:

• AOI inspection

• Lithium battery electrode inspection

• Metal surface inspection

• Dimensional measurement

• Cosmetic defect detection

• General high-speed inspection

For projects without extreme requirements, this is usually the most reliable choice.

5. 5–10μm: Best for High-Speed, Low-Light, and Specialized Imaging

Many people mistakenly assume that larger pixels are outdated.

In reality, in many advanced industrial applications, larger pixels are even more important.

Typical scenarios include:

• High-speed imaging

• Line scan inspection

• Low-light environments

• Fluorescence imaging

• SWIR short-wave infrared imaging

The core advantage is straightforward:

higher light collection and better signal-to-noise ratio

This becomes particularly important under short exposure conditions.

For example, in high-speed production lines, exposure times may only be tens of microseconds.

In such cases, 1.6μm pixels may produce dark images, while 5.5μm or 10μm pixels can still maintain stable brightness.

6. The Professional Approach: Start from Inspection Requirements

Do not start with pixel size.

Start with the inspection target.

For example, if the customer needs to detect a:

0.05 mm scratch

A common engineering rule is that the defect should cover at least 5 pixels.

Then the required pixel precision becomes:

\frac{0.05}{5}=0.01\text{ mm/pixel}

If the field of view is 100 mm, the required horizontal resolution is:

\frac{100}{0.01}=10000

That means at least 10K resolution is required.

Only after defining the required resolution should you determine the appropriate pixel size based on sensor format and lens capability.

This is the most scientific engineering approach.

7. Conclusion: The Best Pixel Size Is the One That Fits the Application

Industrial vision is never just about chasing specifications.

What truly determines inspection performance is not the smallest pixel, but the most suitable pixel for the scenario.

Remember this simple principle:

1.6μm is for seeing finer details, while 10μm is for capturing more stable images.

Choosing the right pixel size is often more important than blindly pursuing higher resolution.

You may contact us at chenguo@mindvision.com.cn to gain more in-depth technical insights and practical applications in the fields of machine vision and optical imaging.