Collection: Filters for PCB Inspection
For PCB inspection, typical wavelengths used include:
- Blue Light (470 nm): This wavelength is effective for general imaging and identifying surface defects on PCBs.
- Green Light (520 nm): Enhances contrast for certain materials and features, making it useful in various inspection scenarios.
- Red Light (620 nm): Helps in detecting specific features and defects on the PCB.
- Near-Infrared Light (850 nm): Particularly advantageous for penetrating solder masks, allowing for better visibility of copper traces beneath the surface. This wavelength is crucial because it provides higher reflectance from copper, making it easier to identify traces that may be obscured by the solder mask
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Using Filter in PCB Inspection
Original Image: A high-resolution image of the PCB is captured.
Image Processing: The image undergoes initial processing, such as noise reduction and enhancement.
Green Filter Application: A green filter is applied to the processed image. This filter selectively transmits green light, while blocking other colors.
Filtered Image: The resulting image highlights components or features that appear green or have a strong green
component. Defects or anomalies that stand out against the green background become more visible. -
Key benefits of using a green filter in PCB inspection
Defect Detection: Green filters can help to identify defects such as solder voids, misaligned components, or missing parts that may be difficult to detect in the original image.
Component Inspection: Certain components, such as resistors or capacitors, may have a distinct green hue. A green filter can enhance the visibility of these components and facilitate their inspection.
Background Reduction: By filtering out unwanted colors, the green filter can reduce the background noise and improve the contrast of the desired features.
Customization: The choice of filter color can be customized based on the specific requirements of the inspection task. For example, if the PCB contains components with a specific color, a filter matching that color can be used to enhance their visibility.
