Many people have a question when they first encounter industrial cameras:

Now that smartphones all come with color HD cameras, why is black-and-white imaging still commonly used in machine vision inspection?

In fact, the reason is very simple:

In many cases, machine vision is not about “seeing color,” but about “seeing details.”

In industrial cameras, both monochrome and color cameras are common choices.

Are black-and-white cameras really just without color?

Many people believe:

A black-and-white camera simply converts color images into grayscale.

Actually, that’s not the case.

To capture color, a color camera must acquire it through a filter:

· Red

· Green

· Blue

These color information.

In contrast, black-and-white cameras lack this color filter and can capture more light.

Therefore, in many industrial inspection scenarios:

Black-and-white cameras typically:

· Higher sensitivity

· Details are clearer.

· More stable edges

Why do size measurements often use black-and-white cameras?

When measuring dimensions with machine vision, the primary concerns are:

Where is the edge?

For example, when measuring a circular hole:

Need to find:

· The edge of the hole

· Outer circular edge

Then calculate:

· Diameter

· Distance

· Location

At this moment:

Grayscale variations in black-and-white images are more informative than color information.

So:

Outer-diameter measurement, bore‑diameter inspection, and precision positioning often employ black-and-white cameras.

When is a color camera more suitable?

If the detection target is:

“Color.”

That color camera is more suitable.

For example:

· Determine whether the red part has been installed incorrectly.

· Check the label color

· Food Color Classification

These scenes:

A black-and-white camera wouldn’t be suitable.

Can black-and-white cameras also make use of color?

Sure.

In machine vision, it is often:

Use light sources of different colors in conjunction with a black-and-white camera.

For example:

Detect red products.

Using red light irradiation:

The red area will light up.

Switch to another color of light:

The light-and-dark relationships may change.

In this way:

It can also enhance detection performance.

Why don’t smartphones use black-and-white cameras?

Because the objectives of mobile phones and industrial vision differ.

Mobile phone photography:

Pursuit:

· The colors look great.

· Recreate the real scene

Industrial Vision:

Pursuit:

· Stability

· Clear

· Easy to analyze

The machine doesn’t need to look good in photos.

What it needs is:

Easy to judge.

Finally, remember this one sentence.

A color camera sees colors.

A black-and-white camera captures details.

If detected:

Color → Select a color camera.

Size, edges, and defects → Black-and-white cameras are usually more suitable.

When selecting a camera for machine vision, higher-end isn’t always better.

The key is:

What information do you need for your testing task?