Method and apparatus for controlling color balance of a color television system

Claim 3

The apparatus of claim 1, wherein spectral sensitivities of said three photoelectric elements have the characteristics that the three spectral sensitivities of the elements extend differently from each other in the spectral bands, a curve obtained by superposing two curves of the three spectral sensitivities of the elements extends differently in the spectral bands from the other remaining curve of the element, each of said three spectral sensitivities of the elements and at least one of the spectral distribution of the three primary colors overlap each other in extending spectral-bands, and each of said three spectral distributions of the three primary colors and at least one of the spectral sensitivity of the elements overlap each other in their spectral-band extents.

Claim 4

The apparatus of claim 2, further comprising an optical focusing system and a light diffusing plate, the optical focusing system focusing the image of the fluorescent screen on the light diffusing plate, and the photoelectric elements being positioned behind the plate.

Claim 5

The apparatus of claim 2, wherein the input quantities of the reference circuit are provided by another matrix circuit which receives the outputs of said mean circuit as input signals and produces three outputs corresponding with quantities of the three primary colors.

Claim 6

The apparatus of claim 2, wherein the input quantities of the reference circuit are the outputs of said matrix circuit.

Claim 7

The apparatus of claim 5, wherein said matrix circuit has a pair of end terminals across which a sum of outputs of the three primary colors is provided and two intermediate output terminals at which outputs corresponding to quantities of the primary colors are provided, the reference circuit is a voltage-dividing circuit comprising three series-connected resistors of predetermined resistances, both end terminals of the voltage-dividing circuit being connected to both end terminals of the matrix circuit, said voltage dividing circuit having first and second output terminals for outputting first and second outputs at two junction points in the dividing circuit, said circuit for generating color-balance control signal comprising first and second comparators, the first comparator comparing a first output of the matrix circuit with a first output of the reference circuit, and the second comparator comparing a second output of the matrix circuit with a second output of the reference circuit.

Claim 8

The apparatus of claim 2, wherein the matrix circuit has three pairs of output terminals for first, second and third primary colors, the first terminal of the first color output and the second terminal of the third color output being connected to a first end and a second end of the reference circuit which consists of three resistors in series-connection, respectively, said resistors having predetermined resistances for dividing the voltage applied to said first and second ends in a specified ratio and providing the divided voltages at a first and a second intermediate terminal between the resistors, the second terminal of the first color output and the first terminal of the second color output being connected to form a first junction point, the second terminal of the second color output and the first terminal of the third color output being connected to form a second junction point, said first intermediate terminal and said first junction point being connected to the input terminals of a first comparator, said second intermediate terminal and said second junction point being connected to the input terminals of a second comparator, output terminals of the first comparator and the second comparator being connected to the color television system for feeding a first and a third color-balance controlling signal, and output terminals of the first and the second comparators being connected to a computing circuit which provides a signal of the negative of the sum of said outputs of the comparators to the color television system as a second color-balance controlling signal.

Claim 9

An apparatus of claim 2, wherein said mean circuit comprises a means for producing each mean value of the outputs of photoelectric elements in more than six regions of a television picture.

Claim 10

An apparatus of claim 2, wherein said mean circuit is constituted by a series connection of a group of photoelectric elements for generating a signal corresponding to the harmonic mean of the outputs of the photoelectric elements.

Claim 11

An apparatus of claim 9, wherein the reference circuit includes elements having constant values selected to produce outputs r, g and b in accordance with the following inequalities and equation: 0.30 < r = R/(R + G + B) < 0.40 0.30 < g = G/(R + G + B) < 0.35 b = 1 - r - g,

Claim 12

An apparatus of claim 2, wherein said mean circuit produces a mathematical mean of the outputs of the photoelectric elements.

Claim 13

An apparatus of claim 11, wherein the reference circuit includes elements having constant values selected to produce outputs r, g and b in accordance with the following inequalities and equation: 0.30 < r = R/(R + G + B) < 0.38 0.32 < g = G/(R + G + B) < 0.38 b = 1 - r - g,

Claim 14

An apparatus of claim 2, wherein said mean circuit produces a geometric mean of the outputs of the photoelectric elements.

Claim 15

An apparatus of claim 13, wherein the reference circuit includes elements having constant values selected to produce outputs r, g and b in accordance with the following inequalities and equation: 0.30 < r = R/(R + G + B) < 0.38 0.30 < g = G/(R + G + B) < 0.38 b = 1 - r - g,

Claim 16

An apparatus of claim 2, wherein photoelectric elements have spectral sensitivities corresponding to the spectral energy distributions of the primary colors, respectively.

Claim 19

The method of claim 16, including the steps of measuring the energies of three primary colors in different regions on the fluorescent screen of the monitor television receiver of the system, converting the output signal of a color television signal to an encoded signal for modulating carrier signals in a transmitter and supplying the encoded signal to the monitor television receiver.

Claim 20

The method of claim 16, wherein the step of generating three mean quantity values includes generating the mean quantity values in accordance with a mathematical mean.

Claim 21

The method of claim 16, wherein the step of generating three mean quantity values includes generating the mean quantity values in accordance with a geometrical mean.

Claim 22

The method of claim 16, wherein the step of generating three mean quantity values includes generating the mean quantity values in accordance with a harmonic mean.