Standard front lighting can cause inconsistent and low contrast of a targets features due to shape, color and surface finish. Using a backlight ensures transmission of the light through the target into the camera. If the target is opaque a silhouette is generated creating a strong contrast and outline for stable inspection. Even if a target is transparent it may have a range of densities to it (such as layered material or liquid in a bottle). Contrast can still be achieved through the changes in the absorption and transmission of light in the target.
Hot spots (halation) means filaments cannot be clearly seen.
The filaments are clearly shown, enabling clear detection of any breaks.
Hot spots and inconsistent contrast occurs across the part making edge detection unstable.
The backlight ensures a silhouette of the target creating a high contrast edge.
Some edge points are unclear and blend into the background.
Complicated outlines and edge points are clearly shown with a sharp contrast.
A foreign object easily blends into the fabric, especially if it is thin or of a similar color.
The extra density from the presence of a foreign object ensures a shadow is created when a back light is used.
The above image displays the relative brightness across a 10000 point grid for the CA-DS Series. Although the intensity varies with each model type, the associated illumination distance and relative brightness across the area are consistent. The brightest areas (shown in red) are considered 100% relative intensity and the dullest areas (shown in green) are considered 0% relative intensity. The images display the intensity differential across the area. By comparing the changes in the intensity differential for different lighting heights (LWD) the ideal lighting range can be realized with the relative brightest points being 100%.
* The above data are representative examples. This is not a guarantee of the product quality.
* LWD is the distance from the illumination to the inspection target.