The following are the technical terms and calculation methods for machine vision industrial lenses:
1. Focal Length: This refers to the distance from the optical center of the lens to the image plane, usually expressed in millimeters (mm). The shorter the focal length, the larger the field of view; the longer the focal length, the smaller the field of view.
2. Aperture: This refers to the size of the lens aperture, usually expressed as an F-number. The smaller the F-number, the larger the aperture; the larger the F-number, the smaller the aperture.
3. Distortion: refers to the deformation of light rays as they pass through the lens during image formation. Common types of distortion include spherical distortion and pincushion distortion.
4. Astigmatism: refers to image distortion caused by imperfections in the shape of a lens. Common aberrations include spherical aberration and pincushion aberration.
5. Resolution: This refers to the smallest object size that the lens can distinguish. The higher the resolution, the clearer the image.
6. Angular Distance: This refers to the distance between two light spots. The smaller the angular distance, the more uniform the image field. It is usually expressed in degrees. In optical imaging, a smaller angular distance results in a more uniform image field. This is because when the angular distance decreases, the light rays become more parallel after passing through the lens, resulting in a clearer and more uniform image.
7. Field of View (FOV): This refers to the range of objects that can be observed within a finite area. In machine vision, FOV typically refers to the field of view that a camera can capture. The larger the FOV, the wider the field of view, and the larger the range of objects that can be observed. This is crucial for scenarios requiring coverage of large areas, such as robotic inspection and drone photography.
8. Pixel Count: This refers to the number of pixels in an image. A higher pixel count results in a sharper image because more pixels provide more detail, leading to greater clarity and accuracy. However, excessive pixels also increase computational complexity and storage requirements. Therefore, a trade-off must be struck when choosing a camera resolution based on the specific application scenario.
Focal length refers to the distance from the optical center to the imaging plane, and it determines the size of the image's field of view. A shorter focal length results in a larger field of view; a longer focal length results in a smaller field of view. In machine vision applications, the size of the field of view is crucial for camera positioning and tracking.
Aperture refers to the size of a lens's aperture, which determines the amount of light that enters the camera through the lens. A larger aperture allows more light into the camera, thus improving image brightness and contrast. However, a larger aperture also reduces depth of field, meaning only objects at the focal point remain sharp, while other areas become blurred.
Distortion, aberrations, and resolution are also important factors affecting image quality. Distortion refers to the image distortion caused by imperfections in the lens shape; common distortions include spherical distortion and pincushion distortion. Aberrations refer to the image distortion caused by imperfections in the lens shape; common aberrations include spherical aberration and pincushion aberration. Resolution refers to the smallest object size that a lens can resolve; the higher the resolution, the clearer the image.
Calculation method:
1. Focal length can be calculated by measuring the object distance and image distance. The formula is: f = (n-1) * u/d, where f is the focal length, n is the number of lenses, u is the object distance, and d is the image distance.
2. The aperture diameter can be calculated by measuring the aperture diameter. The formula is: F = A * tan(θ), where F is the aperture diameter, A is the aperture diameter, and θ is the angle between the focal length and the aperture diameter.
3. Distortion can be calculated by measuring the image height and image width on the imaging plane. The formula is: δ = (1/2 * u^2 + 1/2 * v^2) / f^2, where δ is the distortion, u is the object distance, v is the image distance, and f is the focal length.
4. Aberrations can be calculated by measuring the image height and image width at different positions on the imaging plane. The formula is: δ' = (1/2 * u^2 + 1/2 * v^2) / f^2, where δ' is the aberration, u is the object distance, v is the image distance, and f is the focal length.
5. The field of view can be calculated by measuring the number of pixels on the imaging plane. The formula is: A = n * F * tan(θ), where A is the field of view, n is the number of pixels, F is the aperture, and θ is the angle between the focal length and the aperture diameter.
6. Resolution can be calculated by measuring the distance between two adjacent pixels. The formula is: R = (d/Δx) - ((f/2)^2)/(δ^2), where R is the resolution, d is the distance between two adjacent pixels, Δx is the pixel pitch, f is the focal length, and δ is the distortion.
The above are the technical terms and calculation methods for machine vision industrial lenses. In practical applications, it is necessary to select appropriate lens parameters and algorithms based on the specific scenario for image processing and analysis.
