Schematic representation of the PSF-matched algorithm implemented in t-phot. Top: two objects are clearly detected and separated in the high-resolution detection image (blue line). The same two objects are blended in the low-resolution measurement image and have different colours (red line). Middle: the two objects are isolated in the detection image and are individually smoothed to the PSF of the measurement image, to obtain normalized model templates. Bottom: the intensity of each object is scaled to match the global profile of the measurement image. The scaling factors are found with a global χ² minimization over the object areas. Image from De Santis et al. (2007).