The invention provides a method and a device for online detection of foreign
fiber in cotton. The device comprises a cotton opener, channels, windows, a CCD (
Charge Coupled Device) camera, an illumination
light source, a background plate, a
nozzle array, a foreign
fiber channel, a foreign
fiber collecting unit, a computer, an
electrical equipment cabinet, operating buttons, a frequency conversionfan and a cotton conveyance
pipe. The method comprises the following steps: opening lint cotton; feeding the lint cotton into the detection area of the
CCD camera through the channels; performing theillumination and
CCD camera sampling in three steps, and further collecting the detection results of the three steps for identifying the foreign fiber; calculating the time for nozzles in the corresponding positions to the foreign fiber to open and close by combining the action
delay time of each
nozzle; controlling the corresponding nozzles to operate, so as to remove the foreign fiber; and meanwhile, outputting clean cotton with the foreign fiber being removed from the clean cotton output channel, wherein, by combining the performance parameters of the
CCD camera, the cotton flow rate in the corresponding area of each
nozzle can be calculated from the data obtained through
infrared LED illumination and sampling, and the average cotton flow rate can be further calculated; and then, the cotton flow rate in the channels can be stabilized within a per-determined range by controlling the
frequency conversion fan.