Image reading method and apparatus with coordination function between read value and original density

An image reading method of reading color information on an original picture using an image reading section for converting a given color into an electric signal, an interface section for inputting and outputting a signal from and to an external computer, a color chip having a known density, a scanning section for optically scanning said original picture and a processing section for controlling said scanning section, said interface section and said image reading section and further for performing various calculations, said image reading method comprising the steps of:

• adjusting said image reading section so that a read signal value of said color chip corresponds to the density of said color chip so as to constitute a densitometer;
• measuring density values of highlight and shadow points, designated by an operator, by means of said densitometer;
• correcting density values, designated by said operator, on the basis of the measured density values by means of said processing section so that a plurality of colors obtained by color-separating said highlight and shadow points are balanced;
• and performing a coordination between a read image signal and a density value of said original picture by adjusting said image reading section so that read signal values of said highlight and shadow points become equal to the corrected density values.

An image reading apparatus for reading color information from an original picture, comprising:

• scanning means for optically scanning said original picture and a color chip having a predetermined density value;
• reading means for receiving reflection or transmission light obtained with said scanning means optically scanning said original picture and said color chip and for converting the reflection or transmission light into the corresponding electric signal;
• and
• control means coupled to said scanning means and said reading means to be arranged to control the operation of said scanning means and said reading means and to be responsive to the electric signal outputted from said reading means, said control means operating said scanning means to optically scan said color chip so as to obtain a read signal so as to compare the value of said read signal with the predetermined density value of said color chip so that said control means controls said reading means in accordance with the comparison result whereby the value of said read signal is adjusted to become equal to the predetermined density value of said color chip, and further said control means operates said scanning means to optically scan predetermined highlight and shadow points on said original picture so as to measure density values of said predetermined highlight and shadow points so that density values designated for said highlight and shadow points by an operator are corrected on the basis of the measured density values so as to keep a balance between colors obtained by performing color separation of said highlight and shadow points, and still further said control means again measures density value of said highlight and shadow points to compare the measured density values with the corrected density values so that said control means controls said reading means in accordance with the comparison result whereby the measured density values become equal to said corrected density values.