US 5,289,292 AGranted

Picture element data density conversion apparatus

AssigneeVictor Company of Japan, Ltd.

InventorsMasaru Osada, Takashi Kuriyama

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Abstract

A picture element data density conversion apparatus, enabling arbitrary amounts of data density reduction to be independently selected for the horizontal (i.e. main) and vertical (i.e. secondary) scanning directions of a picture field, executes processing along a continuous path in which horizontally successive input values along each line of the field are first periodically selected and horizontal weighted averaging between specific pairs of these selected values is executed, then periodic selection of successive lines of the horizontal weighted average values thus obtained is executed, and vertical weighting averaging between vertically corresponding pairs of values in the selected line pairs is performed, to obtain density-reduced output data.

Claims8

Dependent claims

A picture element data density conversion apparatus for processing successive input picture element values to effect a reduction of picture element data density within a 2-dimensional input data field formed of a plurality of lines of said input picture element values, each line being oriented in a horizontal scanning direction of the field, and the lines being sequentially arranged in a vertical scanning direction of the field, said input picture element values occurring with a fixed input data period, said lines occurring with a fixed line period, the apparatus comprising:

horizontal digital low pass filter means (3) for operating on said input picture element values to obtain respective horizontally filtered picture element values;
first delay means (14) for delaying said horizontally filtered picture element values by a delay amount which is equal to said input data period multiplied by a first predetermined integer (m.sub.AV), to obtain successive parallel pairs of delayed and non-delayed horizontally filtered picture element values;
horizontal selection means (62) for generating a horizontal selection signal (CK.sub.SEL) for periodically designating respective ones of said pairs of delayed and non-delayed horizontally filtered picture element values, said designation being executed with a horizontal selection period which is equal to said input data period multiplied by said first predetermined integer (m.sub.AV);
horizontal weighting coefficient generating means (5) responsive to said horizontal selection signal (CK.sub.SEL) for detecting, in accordance with a predetermined weighted averaging interpolation period which is a predetermined multiple (m.sub.k) of said horizontal selection period, each of said horizontally filtered delayed and non-delayed picture element value pairs designated by said horizontal selection means for which a valid horizontal weighted average picture element value can be derived, for generating a first validity indication signal in synchronism with said each picture element value pair for which a valid weighted average value can be derived, and for computing respective horizontal weighting coefficients to be applied to said each picture element value pair;
horizontal weighted averaging means (6) for applying said horizontal weighting coefficients to corresponding ones of said pairs of horizontal filtered delayed and non-delayed picture element value pairs, to sequentially derive respective horizontal weighted average picture element values;
vertical digital low pass filter means (7) for operating on said horizontal weighted average picture element values to obtain respective vertically filtered picture element values;
second delay means (9) for delaying said horizontally filtered picture element values by a delay amount which is equal to said line period multiplied by a second predetermined integer (L.sub.AV), to obtain successive parallel pairs of lines of delayed and non-delayed vertically filtered picture element values;
vertical selection means (68) for generating a vertical selection signal (HRD.sub.SEL) for periodically designating respective ones of said pairs of lines of delayed and non-delayed vertically filtered picture element values, said designation being executed with a period which is equal to said line period multiplied by said second predetermined integer (L.sub.AV);
vertical weighting coefficient generating means (8) controlled by said vertical selection signal (HRD.sub.SEL) for detecting, in accordance with a predetermined weighted averaging interpolation period (L.sub.k), each of said vertically filtered delayed and non-delayed picture element value line pairs designated by said vertical selection means for which valid vertical weighted average picture element values can be derived, for generating a second validity indication signal in synchronism with said each line pair for which valid vertical weighted average values can be derived, and for computing a first vertical weighting coefficient to be applied to each picture element value of a first one of said each line pair and a second vertical weighting coefficient to be applied to each picture element value of a second one of said each line pair;
and
vertical weighted averaging means (10) for applying said vertical weighting coefficients to corresponding ones of said line pairs, to sequentially derive respective lines of vertical weighted average picture element values.

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Dependencies are inferred from the claim text.

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Abstract

horizontal digital low pass filter means (3) for operating on said input picture element values to obtain respective horizontally filtered picture element values;
first delay means (14) for delaying said horizontally filtered picture element values by a delay amount which is equal to said input data period multiplied by a first predetermined integer (m.sub.AV), to obtain successive parallel pairs of delayed and non-delayed horizontally filtered picture element values;
horizontal selection means (62) for generating a horizontal selection signal (CK.sub.SEL) for periodically designating respective ones of said pairs of delayed and non-delayed horizontally filtered picture element values, said designation being executed with a horizontal selection period which is equal to said input data period multiplied by said first predetermined integer (m.sub.AV);
horizontal weighting coefficient generating means (5) responsive to said horizontal selection signal (CK.sub.SEL) for detecting, in accordance with a predetermined weighted averaging interpolation period which is a predetermined multiple (m.sub.k) of said horizontal selection period, each of said horizontally filtered delayed and non-delayed picture element value pairs designated by said horizontal selection means for which a valid horizontal weighted average picture element value can be derived, for generating a first validity indication signal in synchronism with said each picture element value pair for which a valid weighted average value can be derived, and for computing respective horizontal weighting coefficients to be applied to said each picture element value pair;
horizontal weighted averaging means (6) for applying said horizontal weighting coefficients to corresponding ones of said pairs of horizontal filtered delayed and non-delayed picture element value pairs, to sequentially derive respective horizontal weighted average picture element values;
vertical digital low pass filter means (7) for operating on said horizontal weighted average picture element values to obtain respective vertically filtered picture element values;
second delay means (9) for delaying said horizontally filtered picture element values by a delay amount which is equal to said line period multiplied by a second predetermined integer (L.sub.AV), to obtain successive parallel pairs of lines of delayed and non-delayed vertically filtered picture element values;
vertical selection means (68) for generating a vertical selection signal (HRD.sub.SEL) for periodically designating respective ones of said pairs of lines of delayed and non-delayed vertically filtered picture element values, said designation being executed with a period which is equal to said line period multiplied by said second predetermined integer (L.sub.AV);
vertical weighting coefficient generating means (8) controlled by said vertical selection signal (HRD.sub.SEL) for detecting, in accordance with a predetermined weighted averaging interpolation period (L.sub.k), each of said vertically filtered delayed and non-delayed picture element value line pairs designated by said vertical selection means for which valid vertical weighted average picture element values can be derived, for generating a second validity indication signal in synchronism with said each line pair for which valid vertical weighted average values can be derived, and for computing a first vertical weighting coefficient to be applied to each picture element value of a first one of said each line pair and a second vertical weighting coefficient to be applied to each picture element value of a second one of said each line pair;
and
vertical weighted averaging means (10) for applying said vertical weighting coefficients to corresponding ones of said line pairs, to sequentially derive respective lines of vertical weighted average picture element values.

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