Depth of field refers to the range of distance over which a subject appears in-focus in a photographic image. An extended depth-of-field camera extends the depth of field without sacrificing resolution or brightness, making it possible to clearly capture a subject without adjusting interval and angle between subject and camera. Scenes that used to require multiple cameras or readjusting focus can now be captured at once with a single camera. Because components for focus adjustment are no longer necessary, our extended depth-of-field camera has excellent stability and reliability. Further, a compact machine vision can be realized, enabling applications in a variety of fields such as factory automation (FA), distribution, security, and personal applications.
Our extended depth-of-field camera comprises a specialized lens and a specialized camera with a built-in image processor. Depth-of-field can be extended with a typical camera by using a smaller aperture, but the image becomes darker. With our camera, the depth-of-field can be extended while maintaining brightness. This is realized by a combination of a uniquely designed specialized lens and image processing by an IC built in the camera body.
Whereas capturing subjects in both the foreground and the background previously involved multiple cameras or altering the position of the camera, it is now possible to keep both the foreground and the background in focus without focus adjustment. As a result, our cameras can be utilized for QR code recognition and object recognition on moving production lines, for example.
Whereas capturing oblique subjects previously required multiple cameras or focus adjustment, it is now possible to keep an oblique subject entirely in focus without focus adjustment. As a result, multiple images no longer need to be connected together after separately capturing near and distant portions of a subject. Instead, information on the entire subject can be captured in a single shot. Potential applications include OCR and substrate inspection.
Whereas capturing subjects at different heights and depths previously involved multiple cameras or change of vertical position of the camera, it is now possible to keep multiple subjects at different heights and depths in focus without focus adjustment. Potential applications include object recognition on moving production lines for products of different heights and depths, and image recognition in cases where printed matter is progressively stacked higher.
It is now possible to capture subjects separated in the field by a range of several centimeters, such as imaging inside a can as shown in Figure 6.