Device and method for observing an object, taking into consideration the distance between the device and the object

A device for observing an object, comprising:

• an excitation-light source configured to produce, in an excitation spectral band, an excitation beam that propagates toward the object;
• a distance sensor including a rangefinding-light source configured to emit, in a rangefinding spectral band, a rangefinding beam that propagates toward the object, and including a rangefinding-light sensor configured to detect rangefinding light reflected, in the rangefinding spectral band, by the object;
• a light guide configured to project the excitation beam and the rangefinding beam toward the object, in a single projection solid angle so as to form an illuminated field, the illuminated field corresponding to an intersection of said projection solid angle with the object;
• an emission-image sensor configured to collect emission light emitted, in an emission spectral band, by the object under effect of the excitation beam, the emission-image sensor configured to acquire an emission image based on the collected emission light, the emission image corresponding to a distribution of emission light within the illuminated field;
• the distance sensor configured to measure, based on a duration between the emission of the rangefinding beam by the rangefinding-light source and the detection, by the rangefinding-light sensor, of the rangefinding light reflected by the object, a smallest distance between a distal end of the light guide and the object within the illuminated field, the smallest distance corresponding to the distance between the distal end of the light guide and a point of the surface of the object said point being the closest point, within the illuminated field, to said distal end of the light guide;
• and
• a modulator configured to adjust, based on the measured smallest distance between the distal end of the light guide and the object, a power of the excitation beam such that a power delivered by the excitation beam to the object as the light guide moves with relation to the object is below a predetermined maximum permitted power to avoid drying or burning the object.