3.5mm Dot Grid Target | 7mm Pitch | Fulteng – Fulteng - Optomechanical and Components Workshop

3.5mm Dot Grid Target | Aluminum | 70x70mm | Positive

$29.55

DOTMTX-ALU-70x70-D3.5-S7

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What payment methods do you accept?

We accept common online payment methods, including credit card, Apple Pay, Google Pay, and other available checkout options.

Can I cancel my order and get a refund after payment?

Yes. If you contact us within 1 day after placing the order, the payment can usually be refunded before the order is processed.

Please contact us at admin@fulteng.com as soon as possible with your order details.

How long does shipment take?

Order preparation usually takes 3–5 working days before shipment.

After the order is shipped, international delivery usually takes around 3–10 days, depending on the destination country and local delivery process.

How will my order be delivered?

We use e-commerce logistics to deliver the order to you.

The general process is:

Order processing — payment is checked and stock is confirmed.
Packing — the product is picked, packed, and prepared for shipment.
Carrier hand-off — the package is passed to the logistics provider.
Last-mile delivery — the local courier delivers the package to your address or collection point.

When will I receive the tracking number?

The tracking number is usually available only after the package reaches the last-mile courier stage.

This means tracking may not appear immediately after the order is packed or shipped.

Can I return a standard product?

Yes. Standard products can be returned for any reason within 7 days after you receive the goods.

Please note:

The item should be returned in its original condition.
The return shipping cost is paid by the customer.
The standard return shipping cost is USD $35.

Can I return a custom product?

Custom products are made or prepared according to your specific requirements, so they usually cannot be returned.

Custom products can only be returned or handled if there is a confirmed quality problem with the product.

3.5mm dot grid calibration target on aluminum for lens distortion measurement, camera calibration, machine vision setup, and optical system verification.

Part number DOTMTX-ALU-70x70-D3.5-S7. External dimension 70x70mm, useful pattern area 56x56mm, dot size 3.5mm, pitch 7mm, array 7x7, accuracy ±5.0μm, Positive polarity.

What is a Dot Grid Target

The feature points of the dot matrix calibration plate are evenly spaced circles. The center coordinates are determined by ellipse fitting; the accuracy of the center depends on the sharpness of the circle's edges and the degree of distortion.

Why to use Dot Grid Target?

Unlike a checkerboard pattern, the center of the circle is "calculated" through mathematical fitting, rather than being directly determined by geometric boundaries.

This design has several key advantages: It remains an ellipse even under perspective distortion: When the camera is tilted, the circle becomes an ellipse, but the center of the ellipse remains the same as the center of the circle (this mathematical property is crucial). It's better suited for large-angle calibration: The center can still be accurately extracted even at a 45° tilt. It has a denser density of feature points: More feature points can be placed within the same area.

Key features: Ellipse fitting for center extraction: Utilizing the property that perspective transformation does not change the position of the ellipse's center, accuracy is guaranteed. Strong resistance to perspective distortion: Feature points can still be accurately extracted even when shooting at an angle. Suitable for industrial environments: It has more lenient requirements for installation angles compared to a checkerboard pattern.

Checkerboard Target vs Dot Grid Target

Checkerboard Pattern vs. Dot Grid

Feature Extraction Accuracy: 0.01~0.05px vs. 0.01~0.1px

Perspective Distortion Resistance: Weak vs. Stronger (Ellipse Fitting)

Tilting Tolerance Angle: ≤30° vs. ≤45°

Occlusion Tolerance: Low vs. Medium

Software Support: Wide vs. Wide

Calibration Board Cost: Medium vs. Medium