Extended depth of field in images through complex amplitude pre-processing and optimized digital post-processing

• Pre-processing optical system and cost-effective image post-processing.
• Proposed technique provides images with high resolution and extended depth of field.
• The universal image quality index is around 1 for all treated images.

Many applications require images with high resolution and an extended depth of field. Directly changing the depth of field in optical systems results in losing resolution and information from the captured scene. Different methods have been proposed for carrying out the task of extending the depth of field. Traditional techniques consist of optical-system manipulation by reducing the pupil aperture along with the image resolution. Other methods propose the use of optical arrays with computing-intensive digital post-processing for extending the depth of field. This work proposes a pre-processing optical system and a cost-effective post-processing digital treatment based on an optimized Kalman filter to extend the depth of field in images. Results demonstrate that the proposed pre-processing and post-processing techniques provide images with high resolution and extended depth of field for different focalization errors without requiring optical system calibration. In assessing the resulting image through the universal image quality index, this technique proves superior.