Reivindicaciones

1. High spatial resolution pyrometer characterized in that it is provided with at least one multi-core fiber (2) and a spatial filter (4), wherein said multi-core fiber has a number N=>2 of cores (3) that are transformed into at least two output fibers (5) by means of said spatial filter (4), said output fibers (5) being connected to a temperature measurement system (6), wherein the temperature measurement system comprises a wavelength-sensitive demultiplexer (8) with at least two outputs to spatially separate the spectrum of the signal collected by each of the cores (3). 2. Pyrometer according to claim 1 characterized in that each output fiber (5) of the spatial filter (4) is connected to a conditioning block (6a) formed by a photodetector (9) and an amplifier (10). 3. Pyrometer according to claim 1 characterized in that the temperature measurement system (6) comprises a wavelength-sensitive demultiplexer (8) with N outputs and a photodetector (9) and an amplifier (10) for each of the outputs. 4. Pyrometer according to claim 2 characterized in that the temperature measurement system (6) is provided with a single conditioning block (6a) and an M:1 switch that connects each of the output fibers (5) of the spatial filter (4) with the input of the wavelength-sensitive demultiplexer (8) of the conditioning block (6a) of the temperature measurement system (6). 5. Pyrometer according to claims 3 or 4 characterized in that at least two output fibers (5) of the spatial filter (4) are combined with a M:1 switch whose output is connected to the wavelength-sensitive demultiplexer (8) of the conditioning block (6a) of the temperature measurement system (6). 6. Pyrometer according to any of the previous claims characterized in that it is provided with a calibration system (7a,7b,13, 14,15, 16, 20). 7. Pyrometer according to claim 6 characterized in that the calibration system comprises a light source (16) and a fluorescent sample (20) for fluorescence calibration. 8. Pyrometer according to claim 6 characterized in that the calibration system comprises a light source (16) and a reflector element (14) for in-situ calibration. 9. Pyrometer according to claim 6 characterized in that the calibration system comprises a light source (16) and a reference system (15). 10. Pyrometer according to any of the previous claims characterized in that one of the cores has a pointing function (18). 11. Pyrometer according to any of the previous claims characterized in that the cores (3) of the multi-core fiber (2) have different sizes so that their measurement capacity has different spatial resolutions and different temperature ranges depending on the size of each of said cores.