Transitory scanning speed phase compensation using luminance edge detection

Color imaging apparatus wherein a color image is focused on a photoelectrical conversion target of a color image pickup tube through a color stripe filter and converted to an electrostatic image which is scanned in line-by-line raster form by an electron beam under the control of a deflection system in response to horizontal and vertical sync pulses to generate a color-multiplexed video signal from said photoelectrical conversion target, said color stripe filter comprising a plurality of recurrent groups of different color stripes successively arranged at periodic intervals so that said video signal has a frequency inversely proportional to the intervals at which said recurrent groups are arranged, said video signal varying in phase with the relative values of primary color components contained in the color image passing through the stripes of each group and in amplitude with the intensity of said primary color components, comprising:

• a field memory;
• read-write means for writing into the memory, during a write-in mode, a reference signal having a duration of at least one field derived from said target when the target is uniformly illuminated by light of a predetermined color passing through said color stripe filter and repeatedly reading the field memory during a read-out mode to generate a constant-amplitude reference video signal having a reference phase;
• edge detector means responsive to leading and trailing edges of said luminance signal and generating therefrom a phase control signal representative of a rapid speed variation of said electron beam in the direction of line scan caused by a transitory variation of charges of said electrostatic image;
• variable delay line means responsive to said phase control signal for controlling the phase of said color-multiplexed video signal with respect to the leading and trailing edges of said luminance signal;
• and
• means for deriving a pair of color component signals from said phase-controlled color-multiplexed video signal and said reference video signal.

Color imaging apparatus wherein a color image is focused on a photoelectrical conversion target of a color image pickup tube through a color stripe filter and converted to an electrostatic image which is scanned in raster form by an electron beam under the control of a deflection system in response to horizontal and vertical sync pulses to generate a color-multiplexed video signal from said photoelectrical conversion target, said color stripe filter comprising a plurality of recurrent groups of different color stripes successively arranged at periodic intervals so that said video signal has a frequency inversely proportional to the intervals at which said recurrent groups are arranged, said video signal varying in phase with the relative values of primary color components contained in the color image passing through the stripes of each group and in amplitude with the intensity of said primary color components, comprising:

• a field memory;
• read-write means for writing into the memory, during a write-in mode, a reference signal having a duration of at least one field derived from said target when the target is uniformly illuminated by light of a predetermined color passing through said color stripe filter and repeatedly reading the field memory during a read-out mode to generate a constant-amplitude reference video signal having a reference phase;
• edge detector means responsive to leading and trailing edges of said luminance signal and generating therefrom a phase control signal representative of a rapid speed variation of said electron beam in the direction of line scan caused by a transitory variation of charges of said electrostatic image;
• phase control means responsive to said phase control signal for controlling the phase of said reference video signal read out of said memory with respect to the leading and trailing edges of said luminance signal;
• and
• means for deriving a pair of color component signals from said color-multiplexed video signal and said phase controlled reference video signal.

Color imaging apparatus wherein an optical image is focused on a photoelectrical conversion target of a color image pickup tube through a color stripe filter having a plurality of successively arranged recurrent groups of different color stripes and converted to an electrostatic image which is scanned in rectangular raster form by an electron beam to generate a luminance signal and a color-multiplexed video signal, wherein said color-multiplexed video signal has a frequency inversely proportional to the intervals at which said recurrent groups are arranged, said color-multiplexed video signal varying in phase with the relative values of primary color components contained in the optical image passing through the stripes of each group and in amplitude with the intensity of said primary color components, comprising:

• first and second delay means connected in series for introducing first and second substantially equal delay times to said luminance signal;
• means for multiplying the amplitude of an output signal from said first delay means;
• adder means for summing the multiplied signal, an output signal from said second delay means and the non-delayed luminance signal and producing first pulses of first and second polarities immediately following the leading edge of the non-delayed luminance signal and second pulses of the second and first polarities immediately following the trailing edge of the non-delayed luminance signal;
• a field memory;
• read-write means for writing into the memory, during a write-in mode, a reference carrier having a duration of at least one field derived from said target when the target is uniformly illuminated by light of a predetermined color passing through said color stripe filter and repeatedly reading the memory during a read-out mode to generate a constant-amplitude reference signal having a reference phase;
• frequency control means for controlling the frequency of said reference signal read out of said memory in response to an output signal from said adder means;
• and
• means responsive to said color-multiplexed video signal and said frequency-controlled reference signal for deriving color difference signals.

Color imaging apparatus wherein an optical image is focused on a photoelectrical conversion target of a color image pickup tube through a color stripe filter having a plurality of successively arranged recurrent groups of different color stripes and converted to an electrostatic image which is scanned in rectangular raster form by an electron beam to generate a luminance signal and a color-multiplexed video signal, comprising:

• means including first and second line memories for alternately storing said luminance signal in a first direction and alternately reading the stored luminance signal out of the first and second line memories in a second direction opposite to said first direction;
• an integrator for integrating an output signal from said first and second line memories;
• means including third and fourth line memories for alternately storing an output signal from said integrator in one direction and alternately reading the stored signal out of the third and fourth line memories in another direction opposite to the first direction;
• a differentiator for differentiating said luminance signal;
• a differential amplifier having a first input responsive to said luminance signal and a second input responsive to an output signal from said third and fourth line memories;
• means for summing output signals from said differentiator and said differential amplifier to generate a phase control signal;
• and
• phase control means for phase-controlling said color-multiplexed signal in response to said phase control signal.

Color imaging apparatus wherein an optical image is focused on a photoelectrical conversion target of a color image pickup tube through a color stripe filter having a plurality of successively arranged recurrent groups of different color stripes and converted to an electrostatic image which is scanned in rectangular raster form by an electron beam to generate a luminance signal and a color-multiplexed video signal, comprising;

• means including first and second line memories for alternately storing said luminance signal in a first direction and alternately reading the stored luminance signal out of the first and second line memories in a second direction opposite to said first direction;
• a first differentiator for differentiating an output signal from said first and second line memories;
• means for inverting the polarity of an output signal from said differentiator;
• means including third and fourth line memories for alternately storing an output signal from said polarity inverting means in one direction and alternately reading the stored signal out of the third and fourth line memories in another direction opposite to the first direction;
• a second differentiator for differentiating said luminance signal;
• means for summing output signals from said second differentiator and said third and fourth line memories to generate a phase control signal;
• and
• phase control means for phase-controlling said color-multiplexed video signal in response to said phase control signal.