1. A color calibrator of a display device, the color calibrator comprising: a color estimator, receiving digital counts of a first initial color, a second initial color and a third initial color of an image signal, the color estimator comprising: a first operator, performing a mathematical operation on the digital counts of the first initial color, the second initial color and the third initial color to obtain a first gray value digital count, a mixed color digital count and an initial color digital count; a gray value electrical-optical converter, converting the gray value digital count according to a plurality of gray value conversion curves and a plurality of mixed color conversion curves to respectively generate a first conversion output and a second conversion output; a mixed color electrical-optical converter, converting the mixed color digital count according to the plurality of mixed color conversion curves and a plurality of initial color conversion curves to respectively generate a third conversion output and a fourth conversion output; an initial color electrical-optical converter, converting the initial color digital count according to the plurality of initial color conversion curves to generate a fifth conversion output; a plurality of linear transformers, respectively receiving the first conversion output, the second conversion output, the third conversion output, the fourth conversion output and the fifth conversion output and performing linear transformations to respectively obtain a first linear transformation output, a second linear transformation output, a third linear transformation output, a fourth linear transformation output and a fifth linear transformation output; and a weighting operator, receiving the first linear transformation output, the second linear transformation output, the third linear transformation output, the fourth linear transformation output and the fifth linear transformation output, and a gray weighting value, a mixed color weighting value and an initial color weighting value, and generating an analysis output signal based on an operation result of the first liner transformation output and the gray weight value, an operation result of the second linear transformation output, the third linear transformation output and the mixed color weighting value, and an operation result of the fourth linear transformation output and the fifth linear transformation output and the initial color weight value; and an electrical driving signal generator, receiving the digital counts of the first initial color, the second initial color and the third initial color of the image signal, the electrical driving signal generator comprising: a target electrical-optical converter, receiving the digital counts of the first initial color, the second initial color and the third initial color to generate a first target initial color, a second target initial color and a third target initial color; a second operator, receiving the first target initial color, the second target initial color and the third target initial color and performing the mathematical operation to obtain a target gray value digital count, a target mixed color digital count and a target initial color digital count; and an electrical-optical inverse converter, receiving the target gray value digital count, the target mixed color digital count and the target initial color digital count and performing an inverse conversion on the target gray value digital count, the target mixed color digital count and the target initial color digital count to generate an applied gray value digital count, an applied mixed color digital count and an applied initial color digital count, wherein the inverse conversion is an inversion operation of a signal conversion and operation performed by the gray value electrical-optical converter, the mixed color electrical-optical converter, the initial color electrical-optical converter, the plurality of linear transformers and the weighting operator.