A portable industrial instrument for performing, in an integrated and two-way manner, interferometric fringe projection and shearography, on an object to be tested, comprising. - a two-way interferometer including means to generate a bidirectional circularly polarized light beam; - a coherent or quasi-coherent light projection device; - a recording or imaging device; - a first location where said two-way interferometer is located to be functionally associated with the coherent or quasi-coherent light projection device and a second location where said interferometer is located to be functionally associated with the recording or imaging device; - a computational device, including a video and analysis display; - an excitation device dedicated to the shearographic or fringe projection measurements; so that, when the two-way interferometer is associated with the coherent or quasi-coherent projection device at the first location, the instrument is able to measure the 3D shape of the object by interferometric fringe projection, also known as moiré method, and, when the two-way interferometer is associated with the recording or imaging device at the second location, the instrument is able to perform shearographic measurements on the object, the direction of the traversing light beam in the interferometer being reversed when shifting from one measurement configuration to the other one,the displacement direction of the coherent r quasi-coherent light being reversed between the two operation modes, said instrument being characterised in that: - the two-way interferometer is reversible and symmetric about a Savart plate, which is central and - a "translation" device for precisely displacing said two-way interferometer from said first location to said second location and vice versa, comprising a rail that is curved on one of its ends, having a "J" shape, so that the precision displacement of the interferometer corresponds to a combination of a strict geometric translation with a rotation of an angle not exceeding 45°. - a two-way interferometer including means to generate a bidirectional circularly polarized light beam; - a coherent or quasi-coherent light projection device; - a recording or imaging device; - a first location where said two-way interferometer is located to be functionally associated with the coherent or quasi-coherent light projection device and a second location where said interferometer is located to be functionally associated with the recording or imaging device; - a computational device, including a video and analysis display; - an excitation device dedicated to the shearographic or fringe projection measurements; so that, when the two-way interferometer is associated with the coherent or quasi-coherent projection device at the first location, the instrument is able to measure the 3D shape of the object by interferometric fringe projection, also known as moiré method, and, when the two-way interferometer is associated with the recording or imaging device at the second location, the instrument is able to perform shearographic measurements on the object, the direction of the traversing light beam in the interferometer being reversed when shifting from one measurement configuration to the other one,the displacement direction of the coherent r quasi-coherent light being reversed between the two operation modes, said instrument being characterised in that: - the two-way interferometer is reversible and symmetric about a Savart plate, which is central and - a "translation" device for precisely displacing said two-way interferometer from said first location to said second location and vice versa, comprising a rail that is curved on one of its ends, having a "J" shape, so that the precision displacement of the interferometer corresponds to a combination of a strict geometric translation with a rotation of an angle not exceeding 45°.