Detail Representation
Energy Definition
Examples

Detail Representation

A detail is represented by an energy. The confidence we have the detail is present is an increasing function of the energy. Searching for the details is done by optimizing the energy. We search the position, scale and sharing of the detail for which the energy is maximum.

Energy Definition

The energy is a sum of gradient and grey level terms. The gradient term are summed on a band surrounding the supposed detail and the grey level terms are summed on an inside and an outside area. The gradient is said to be hot-cold if the inside is warmer than the outside. To reach gain and contrast invariance, the inside and outside grey level are expressed in percent of the histogram of grey levels. To add a detail in the database, one must give the detail shape, the weights of the energy function and eventually the inside and outside region.

Examples

For a (hot) wheel, one could set the gradient hot-cold weight to 1 and the other weights to 0.
For the engine, which is hot but whose border is not accurately defined on the image, one could define a detail at the map position of the engine (smaller than the hot region seen on the image) with an inside area that should have grey value 0.8. This means that the points should be in the 20 percent hottest points.
On the following images, one sees some found details and the corresponding energy.