I integrated the LiDAR data with WorldView-2 data for the canopy height model. The tree canopy height model (CHM) was computed as the difference between tree canopy hits (DSM) and corresponding LiDAR derived terrain (DTM) elevation values. Both WV-2 and CHM used, in eCognition for tree level classification. Spectral information WV-2 and tree height from CHM.

From your question its not clear for which application, you are targeting both active and passive optical data integration. If you can elaborate that will be nice to answer.

You can use some cooresponding feature points\lines\planes to integrate the lidar point cloud with the aerial optical image. In urban area, the lineary features is the best .

Hi there,

As far as I know there is no readily available algorithm to integrate LIDAR and aerial optical image. 

They are completely different data sets. A lidar point cloud is generated either in a PRCS (Project coordinate system) or GLCS (Global coordinate system) and it has a unique x, y and z coordinates. Similarly, with the photogrammetric system (PGCS), photogrammetric coordinate system it also has unique x, y and z

If you want to tie both photogrammteric and LiDAR system in space, you need to have GCP's (Ground control points) for which you need to take a GPS reading and then extract them in the image data and then register them with the PRCS or GLCS of Lidar point cloud,

However, if you use a TLS(terrestrail laser scanner) equipped with a camera, after the scanner collected the point cloud, the camera takes the pictures in the particular orientation. The proprietary software of the laser scanner merge the point cloud and photographic image automatically.

Hope it helps

cheers

vishal