Digital Video Processing for Engineers

19

Segmentation and Focus

Steve Fielding

Base2Designs

Chapter Outline

19.1 Measuring Focus

19.1.1 Gradient Techniques

19.1.2 Variance Techniques

19.2 Segmentation

19.2.1 Template Matching

19.2.2 FPGA Implementation

The majority of image-processing algorithms require a properly focused image for best results. For some applications this may not be difficult to achieve because the camera capturing the image will have a large depth of field: objects at a wide range of distances from the camera will all appear in focus without having to adjust the focus of the camera. However, for cameras that have narrow depth of field, the image will not always be in focus, and there needs to be some way of assigning a focus score to an image – a measure of focus “goodness”. ...