This paper presents a system developed for measuring yarn hairiness using a coherent optical signal processing technique, in steps of 1 mm. The system hardware is divided into two main parts: optical, for establishing an image regarding yarn hairiness and electronic, which converts the optical signal to a proportional voltage signal. Additionally, software using LabVIEW^TM was also designed to acquire the output voltage with a data acquisition board (DAQ) and to perform the corresponding data processing. This system is able to quantify the traditional commercial hairniness parameters, as sH (%), CVH (%), H and spectral analysis based on FFT. In addition several other parameters, novel in textile characterization, such as DRH (%), IDRH (%), UH (%) and spectral analysis based on FWHT and FDFI are readily available. The results obtained using this system to characterize a 4.20 g/Km cotton yarn are presented.