Apparatus for generating an image from a digital video signal

An image processing apparatus responsive to a digital input signal, said apparatus comprising:

• a raster scanning print engine for generating a series of successive scan lines;
• means for generating a pulse-width-modulated signal from a digital input signal input to said apparatus;
• and
• means for applying said pulse-width-modulated signal to said print engine to cause said print engine to generate each said scan line as a succession of line-segments, the lengths of which are controlled in accordance with said pulse-width-modulated signal to produce a variable density line screen from said line segments, said line screen comprising a plurality of columns of said line segments, wherein said digital input signal ranges between maximum and minimum values and wherein said pulse-width-modulated signal generating means generates a pulse-width-modulated signal having a predetermined pulse width when said digital input signal has the minimum value.

An image processing apparatus responsive to a digital input signal, said apparatus comprising:

• a raster scanning print engine for generating a series of successive scan lines;
• means for generating a pulse-width modulated signal from a digital input signal input to said apparatus;
• and
• means for applying said pulse-width-modulated signal to said print engine to cause said print engine to generate each said scan line as a succession of line-segments, the lengths of which are controlled in accordance with said pulse-width-modulated signal to produce a variable density line screen from said line segments, said line screen comprising a plurality of columns of said line segments wherein said digital input signal ranges between maximum and minimum values and wherein said pulse-width-modulated signal generating means generates a pulse-width-modulated signal having a predetermined pulse width when said digital input signal has the maximum value.

An image processing apparatus for forming an image on a recording medium, said apparatus comprising:

• video signal output means for generating an analog-video signal;
• pattern signal generating means for producing a pattern signal of predetermined period;
• a pulse-width-modulated signal generating means for generating a pulse-width modulated signal in accordance with the analog video signal generated by said video signal output means and said pattern signal generated by said pattern signal generating means;
• and
• image forming means for scanning lines on a recording medium with a beam in accordance with said pulse-width-modulated signal generated by said pulse-width modulated signal generated means thereby forming an image on said recording medium;
• said image forming means including means for generating a synchronizing signal for each line scanned on the recording medium, said pattern signal generating means generating the pattern signal of predetermined period in accordance with said synchronizing signal.

An image processing apparatus comprising:

• digital video signal generating means for generating a digital video signal having a characteristic;
• characteristic converting means for converting the characteristic of said digital video signal generated by said digital video signal generating means and for producing a converted digital video signal therefrom;
• digital-to-analog converting means for converting the converted digital video signal generated by said characteristic converting means into an analog video signal;
• pattern signal generating means for generating a pattern signal of predetermined period;
• and
• pulse-width-modulated signal generating means for generating a pulse-width-modulated signal in accordance with said analog video signal and said pattern signal.

An apparatus for generating an image from a digital video signal comprising:

• A. a raster scanning print engine for generating a series of successive scanning lines;
• B. a digital look up table addressable by said digital video signal;
• C. means for generating form:
• said digital video signal a pulse-width-modulated signal, said pulse-width-modulated signal generating means comprising:
• (1) means for applying said digital video signal as an address to said digital look up table for producing in accordance with said digital look up table a resultant gamma corrected digital signal;
• (2) means for converting said resultant gamma corrected digital signal to an analog video signal;
• (3) means for generating a periodic analog reference signal of predetermined period;
• and
• (4) means for comparing said analog video signal to said periodic analog reference signal thereby to produce said pulse-width-modulated signal;
• and
• D. means for applying said pulse-width modulated signal to said print engine for generating each said scanning line as a succession of line-segments, the length of which are controlled in accordance with said pulse-width-modulated signal to produce a variable density line screen from said line segments, an axis of symmetry of the line screen being substantially normal to the scanning lines.

An image processing apparatus responsive to a digital video signal input thereto, said apparatus comprising:

• a digital-to-analog converting means for converting the digital video signal input to said apparatus into an analog video signal;
• a pattern signal generating means for generating a pattern signal of a predetermined period;
• and
• a pulse-width-modulated signal generating means for generating a pulse-width-modulated signal in accordance with said converted analog video signal and said pattern signal.

Image processing apparatus comprising:

• digital video signal generating means for generating a digital video signal having a characteristic;
• characteristic converting means for converting the characteristic of said digital video signal generated by said digital video signal generating means and for producing a converted digital video signal therefrom, said characteristic converting means including changing means for periodically changing a plurality of factors for converting the characteristic of said digital video signal at a predetermined interval thereby to convert the characteristic of said digital video signal generated by said digital video signal generating means and to produce said converted digital video signal by using said plurality of factors;
• and
• image forming means for forming an image in accordance with said converted digital video signal, said image forming means forming said image by scanning digital video signal;
• wherein said characteristic converting means uses the same ones of said plurality of factors for at least one scanning line scanned by said image forming means, and said changing means changes said plurality of factors after scanning of said at least one scanning line scanned by said scanning means.

Image processing apparatus for forming an image, said apparatus comprising:

• video signal output means for generating an analog video signal;
• pattern signal generating means for producing a pattern signal of predetermined period, one period of said pattern signal corresponding to a plurality of pixels of the analog video signal;
• a pulse-width-modulated signal generating means for generating a pulse-width-modulated signal in accordance with the analog video signal generated by said video signal output means and said pattern signal generated by said pattern signal generating means;
• and
• image forming means for forming an image in accordance with said pulse-width-modulated signal generated by said pulse-width-modulated signal generating means.