A system comprising: a pattern irradiation apparatus (20, 50, 60, 70, 80, 90, 110, 120, 130, 140, 150) comprising: an irradiation apparatus (31, 32, 33, 34) comprising: a light source unit to emit light; and a first diffuser (33a, 51, 111, 121, 131, 141); the pattern irradiation apparatus further comprising an image generator, disposed on a light path of the light exiting from the irradiation apparatus (31, 32, 33, 34), to pass through the light exiting from the irradiation apparatus (31, 32, 33, 34) by applying a given image pattern to the light; and an irradiation unit, disposed on a light path of the light exiting from the image generator, to irradiate the light having the given image pattern that has passed through the image generator to a target object; the system further comprising a three-dimensional measuring apparatus to measure a distance to the target object being irradiated with the light by using the pattern irradiation apparatus (20, 50, 60, 70, 80, 90, 110, 120, 130, 140, 150) in order to enhance the precision of the distance measurement; characterised in that the irradiation apparatus further comprises: a light condenser (32, 32a, 32b, 32c), disposed on a light path of the light emitted from the light source unit, to condense the light emitted from the light source unit, wherein the first diffuser (33a, 51, 111, 121, 131,141) is disposed on a light path of the light exiting from the light condenser (32, 32a, 32b, 32c), to diffuse the light condensed by the light condenser (32, 32a, 32b, 32c); an optical equalizer (34, 61), disposed downstream of the first diffuser (33a, 51, 111, 121, 131,141), to equalize a luminance distribution of the light entering the optical equalizer (34, 61) from the first diffuser (33a, 51, 111, 121, 131,141) and to output the light having the equalized luminance distribution; and a second diffuser, disposed downstream of the optical equalizer (34, 61), to diffuse the light exiting from the optical equalizer (34, 61). a pattern irradiation apparatus (20, 50, 60, 70, 80, 90, 110, 120, 130, 140, 150) comprising: an irradiation apparatus (31, 32, 33, 34) comprising: a light source unit to emit light; and a first diffuser (33a, 51, 111, 121, 131, 141); the pattern irradiation apparatus further comprising an image generator, disposed on a light path of the light exiting from the irradiation apparatus (31, 32, 33, 34), to pass through the light exiting from the irradiation apparatus (31, 32, 33, 34) by applying a given image pattern to the light; and an irradiation unit, disposed on a light path of the light exiting from the image generator, to irradiate the light having the given image pattern that has passed through the image generator to a target object; the system further comprising an irradiation apparatus (31, 32, 33, 34) comprising: a light source unit to emit light; and a first diffuser (33a, 51, 111, 121, 131, 141); the pattern irradiation apparatus further comprising a light source unit to emit light; and a first diffuser (33a, 51, 111, 121, 131, 141); the pattern irradiation apparatus further comprising an image generator, disposed on a light path of the light exiting from the irradiation apparatus (31, 32, 33, 34), to pass through the light exiting from the irradiation apparatus (31, 32, 33, 34) by applying a given image pattern to the light; and an irradiation unit, disposed on a light path of the light exiting from the image generator, to irradiate the light having the given image pattern that has passed through the image generator to a target object; the system further comprising a three-dimensional measuring apparatus to measure a distance to the target object being irradiated with the light by using the pattern irradiation apparatus (20, 50, 60, 70, 80, 90, 110, 120, 130, 140, 150) in order to enhance the precision of the distance measurement; characterised in that the irradiation apparatus further comprises: a light condenser (32, 32a, 32b, 32c), disposed on a light path of the light emitted from the light source unit, to condense the light emitted from the light source unit, wherein the first diffuser (33a, 51, 111, 121, 131,141) is disposed on a light path of the light exiting from the light condenser (32, 32a, 32b, 32c), to diffuse the light condensed by the light condenser (32, 32a, 32b, 32c); an optical equalizer (34, 61), disposed downstream of the first diffuser (33a, 51, 111, 121, 131,141), to equalize a luminance distribution of the light entering the optical equalizer (34, 61) from the first diffuser (33a, 51, 111, 121, 131,141) and to output the light having the equalized luminance distribution; and a second diffuser, disposed downstream of the optical equalizer (34, 61), to diffuse the light exiting from the optical equalizer (34, 61). a light condenser (32, 32a, 32b, 32c), disposed on a light path of the light emitted from the light source unit, to condense the light emitted from the light source unit, wherein the first diffuser (33a, 51, 111, 121, 131,141) is disposed on a light path of the light exiting from the light condenser (32, 32a, 32b, 32c), to diffuse the light condensed by the light condenser (32, 32a, 32b, 32c); an optical equalizer (34, 61), disposed downstream of the first diffuser (33a, 51, 111, 121, 131,141), to equalize a luminance distribution of the light entering the optical equalizer (34, 61) from the first diffuser (33a, 51, 111, 121, 131,141) and to output the light having the equalized luminance distribution; and a second diffuser, disposed downstream of the optical equalizer (34, 61), to diffuse the light exiting from the optical equalizer (34, 61).