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

Now that smartphones all come with color HD cameras, why do machine vision inspections still often rely on black-and-white cameras?

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 filters:

• 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 a black-and-white camera 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 relationship 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?