An imaging signal processing method comprising the step of acquiring a multispectral imaging data using a multispectral imaging color measurement system, the system comprising a dark room of a confined space for multispectral imaging, a sample platform located in said dark room for laying and fastening an object being measured, an imaging device for capturing said object being measured, a controllable illumination device, a filter wheel unit, an imaging signal processing unit and an electronic control unit, said controllable illumination device being located in the dark room comprising at least one lighting tube arranged symmetrically above the object while pointing towards the object; said filter wheel unit being located between said imaging device and said object for filtering light emitted from said controllable illumination device and reflected by said object; said imaging signal processing unit is located within said imaging device for calibrating and reconstructing reflectance of images captured by said imaging device; said electronic control unit having communication connections with said controllable illumination device, said filter wheel unit and said imaging device for controlling said controllable illumination device, said filter wheel unit and said imaging device when in operation, the method further comprising: correcting geometric error caused by optical lens or filters; correcting brightness of imaging signal in each optical channel; estimating an exposure time of a linear working range for a sensor, setting said sensor to operate within said exposure time to convert incident light signal into digital imaging signal; correcting image noise caused by inherent noise source in said sensor; calibrating multi-channel images in the optical channels that are captured through different filters to eliminate offset of content caused by relative misaligned position of the filters in the filter wheel unit, differences in refractive indexes in the filters, a slight objective distance shift between the filters in the filter wheel unit and the object being measured; correcting overlapping imaging signal caused by overlapping effect in each channel, the overlapping effect being caused by one or more times of reflection between the filters and a series of lenses; reconstructing reflectance of the imaging signal; and generating a spectral reflectance image of the object being measured; wherein said correcting overlapping images caused by overlapping effect in each channel comprises: extracting white objects by using an image threshold process comprising determining a threshold T based on image's maximum brightness I max and minimum brightness I min, wherein a pixel with brightness greater than T is considered as a candidate object, and other pixels are considered as the overlapping images; matching each pixel of the entire image being processed with a template by scanning; determining a position of overlapping images caused by the overlapping effect with a maximum correlation coefficient; and eliminating the overlapping effect in the overlapping images in each imaging channel according to corresponding parameters. correcting geometric error caused by optical lens or filters; correcting brightness of imaging signal in each optical channel; estimating an exposure time of a linear working range for a sensor, setting said sensor to operate within said exposure time to convert incident light signal into digital imaging signal; correcting image noise caused by inherent noise source in said sensor; calibrating multi-channel images in the optical channels that are captured through different filters to eliminate offset of content caused by relative misaligned position of the filters in the filter wheel unit, differences in refractive indexes in the filters, a slight objective distance shift between the filters in the filter wheel unit and the object being measured; correcting overlapping imaging signal caused by overlapping effect in each channel, the overlapping effect being caused by one or more times of reflection between the filters and a series of lenses; reconstructing reflectance of the imaging signal; and generating a spectral reflectance image of the object being measured; wherein said correcting overlapping images caused by overlapping effect in each channel comprises: extracting white objects by using an image threshold process comprising determining a threshold T based on image's maximum brightness I max and minimum brightness I min, wherein a pixel with brightness greater than T is considered as a candidate object, and other pixels are considered as the overlapping images; matching each pixel of the entire image being processed with a template by scanning; determining a position of overlapping images caused by the overlapping effect with a maximum correlation coefficient; and eliminating the overlapping effect in the overlapping images in each imaging channel according to corresponding parameters. extracting white objects by using an image threshold process comprising determining a threshold T based on image's maximum brightness I max and minimum brightness I min, wherein a pixel with brightness greater than T is considered as a candidate object, and other pixels are considered as the overlapping images; matching each pixel of the entire image being processed with a template by scanning; determining a position of overlapping images caused by the overlapping effect with a maximum correlation coefficient; and eliminating the overlapping effect in the overlapping images in each imaging channel according to corresponding parameters.