In the field of smartwatch manufacturing, the quality of the watchband, as a key component connecting the watch body and the user's wrist, directly affects the user experience. Among them, the concentricity of the band's round holes is an important quality indicator, which is related to the band's assembly precision, wearing comfort and overall aesthetics. Therefore, it is of vital significance to accurately detect the concentricity of the band holes of smartwatches.

The Importance of Concentricity of Round Holes in Smartwatch Bands

（1）Assembly precision: accurate concentricity of the holes can ensure smooth assembly of the watchband and the watch body, avoiding assembly difficulties or loosening caused by concentricity deviation, improving production efficiency and product quality stability.

（2）Wearing comfort: A band with good concentricity fits the wrist better and reduces the discomfort caused by uneven localized force, bringing users a more comfortable wearing experience.

（3）Aesthetics: From the appearance point of view, the concentric holes make the watchband more symmetrical and aesthetic, which meets the consumers' pursuit of exquisite appearance.

Detection Methods

A: Traditional inspection methods

1、Manual Measurement: Using simple gauges such as calipers, micrometers, etc., the concentricity is estimated by manually measuring the diameters of multiple positions. This method is simple and low-cost, but with low efficiency, limited precision, and influenced by human factors, it is difficult to meet the high-precision inspection needs of mass production.

2、Optical projector detection: the strap is placed on the optical projector, the image of the round hole is enlarged by projection, and the measurement is compared with the standard template. The method is relatively high precision, but the detection speed is slow, and the flexibility is insufficient for the detection of complex shapes of watch bands.

B: Modern Inspection Technology

1、Machine vision inspection: The camera is used to collect the image of the round hole of the watch band, and the image processing algorithm is used to extract the features of the round hole and calculate the concentricity. Machine vision inspection has the advantages of high precision, high speed, non-contact, etc. It can realize automated on-line inspection, greatly improve the inspection efficiency and accuracy, and has become the mainstream method of concentricity inspection of the round hole of the watch band of smart watches.

2、Laser measurement technology: The laser beam is launched to scan the round hole of the watch band, and the position and concentricity of the hole are calculated according to the laser reflection signal. Laser measurement is characterized by high precision, high resolution, fast measurement, etc. It is especially suitable for occasions with extremely high requirements for precision, but the cost of equipment is relatively high.

Components and Principles of Detection Systems

1. Light source: Provide uniform and stable illumination to ensure that the round hole of the strap is clearly imaged in the image, different types of light sources and illumination methods will affect the image quality and inspection accuracy.

2. Camera and lens: the camera is responsible for image acquisition, the lens is used for focusing and imaging, choose the appropriate camera resolution and lens focal length to meet the different precision requirements of the inspection task.

3. Image acquisition card: the analog image signal captured by the camera is converted into a digital signal and transmitted to the computer for processing. 4.

4. Computer and image processing software: running image processing algorithms, pre-processing of the collected images, feature extraction and concentricity calculation, according to the preset tolerance range to determine whether the test results are qualified.

Challenges and solutions

① Strap Material and Surface Characteristics: Strap made of different materials, such as metal, plastic, leather, etc., have different surface reflectance and texture, which may affect the quality of image acquisition. The solution is to select appropriate light sources and image processing algorithms for different materials to enhance the image characteristics.

② Vibration and environmental interference on the production line: On the production line, factors such as equipment vibration and environmental light changes may lead to detection errors. Interference can be reduced by adopting a stable inspection platform, optimizing the inspection environment and using inspection equipment with strong anti-interference capability.

③ Balance between detection accuracy and speed: With the improvement of production efficiency requirements, it is necessary to improve detection speed while ensuring detection accuracy. This can be achieved by optimizing image processing algorithms, using high-performance hardware equipment and parallel computing technology.