Calibration system and method for color image scanning

Claim 2

In an image scanning system having a light source and a plurality of photodetector cells arranged in at least one set comprising an othogonal pattern of plural rows and columns, means for scanning said photodetector cells with image light originating at said light source and reflected from a subject in a direction transverse to said rows, and means for operating said cells so that each row is exposed to a linear increment of said image light the improvement comprising: means for exposing at least the first cell in each row to the full spectrum of light emanating from said light source; means for summing signals provided by said photodetector cells in each column of each set to provide column signals in an ordered sequence from a first of said columns to a last of said columns; means for processing at least said first column signal to obtain a calibration factor representing variation of light value emanating from said light source from a fixed value for said one set of photodetector cells; and means for multiplying each column signal provided for each column of said one set of photodetector cells succeeding said at least first column signal by said calibration factor.

Claim 3

The image scanning system of claim 1, wherein the number of photodetector cells in each row is on the order of 2,000 and wherein the number of cells in each row exposed to the full spectrum of light emanating from said light source is in the range of between 1 and 20.

Claim 4

The image scanning system of claim 1, wherein said means for exposing the first cell in each row to the full spectrum of light emanating from said source includes a white reference patch aligned with a portion of the subject from which light is reflected.

Claim 5

The image scanning system of claim 1, wherein said rows of photodetector cells are arranged in plural sets so that the cells of each set detect a spectral portion of light different from the spectral portion of light detected by another of said sets, whereby said calibration factor represents light value variation in the respective spectral portions of light to which each row is exposed.

Claim 6

The image scanning system of claim 1, wherein said calibration factor is of a numerical value greater than one.

Claim 7

In an image scanning system having a light source and a color balanced detector array including plural sets of detectors, each of said detectors detecting light from a subject, the detectors of each of said detector sets detecting a spectral portion of the light different from the spectral portion of the light detected by the detectors of another of said detector sets; means for scanning light from successive portions of the subject to said detector sets along a predetermined scanning path; and wherein each of said detector sets comprises a plurality of detectors arranged in rows and columns, the columns being parallel to said scanning path and the rows being transverse to said scanning path, each of said detectors providing a signal in response to a detection of light; and means synchronized with said scanning means for triggering said detectors to provide their respective signals in synchronism with the scanning along said scanning path; and means for retrieving column signals of the respective detector sets to provide imaging data of said subject, the improvement comprising: means for exposing at least the first detector in each row of a set of detectors to the full spectrum of light emanating from said light source; means for summing signals provided by said detectors in each column of each set to provide column signals in an ordered sequence from a first one of the columns to a last one of the columns; means for processing at least said first column signal of each said set to obtain a calibration factor representing variation of light value emanating from said light source from a fixed value for that set; and means for multiplying each said column signal succeeding said at least first column signal for that set by said calibration factor.

Claim 8

In an image scanning system having a light source and a color balanced detector array including plural sets of detectors, each of said detectors detecting light from a subject, the detectors of each of said detector sets detecting a spectral portion of the light different from the spectral portion of the light detected by the detectors of another of said detector sets; means for scanning light from successive portions of the subject to said detector sets along a predetermined scanning path; and wherein each of said detector sets comprises a plurality of detectors arranged in rows and columns, the columns being parallel to said scanning path and the rows being transverse to said scanning path, each of said detectors providing a signal in response to a detection of light; and means synchronized with said scanning means for triggering said detectors to provide their respective signals in synchronism with the scanning along said scanning path; and means for retrieving column signals of the respective detector sets to provide imaging data of said subject, the improvement comprising: means for exposing at least the first detector in each row of a set of detectors to the full spectrum of light emanating from said light source; means for summing signals provided by said detectors in each column of each set to provide column signals in an ordered sequence from a first one of the columns to a last one of the columns; means for processing at least said first column signal of each said set to obtain a calibration factor representing variation of light value emanating from said light source from a fixed value for that set; and means for multiplying each said column signal succeeding said at least first column signal for that set by said calibration factor.

Claim 9

The image scanning system of claim 6, wherein said means for exposing at least the first detector in each row to the full spectrum of light emanating from said light source comprises a white reference patch adjacent to the subject from which light is reflected to the remaining detectors in each row.

Claim 10

The image scanning system of claim 7, in which the subject is advanced linearly relative to a fixed band of light emanating from said light source and wherein said a white reference patch is positioned along one side of the subject.

Claim 11

The image scanning system of claim 8, wherein said white reference patch is fixed in said band of illumination.