Method and apparatus for enlarging gray scale images

Claim 2

Apparatus for enlarging, by a given factor of scale, a gray scale input image having ordered rows and columns of digitized picture elements (pixels), each said pixel of said input image having a gray scale value, the apparatus comprising: an input register for receiving gray scale pixel values of the input image, said input register having a plurality of pixel value storage locations; a scale factor input register for receiving the given factor of scale; means coupled to the scale factor input register for generating an ordered sequence of numbers as a function of the given factor of scale; means for associating one number of said ordered sequence of numbers with each pixel and each row of pixels in the input image; means coupled to the input register and the means for generating for leaving a vacant pixel value storage location between received pixel values of the input image, said vacant pixel value storage location being adjacent the pixel value storage location of each pixel of the input image associated with a number of a predetermined value and for leaving a plurality of vacant pixel storage locations between received pixels of the input image, each of said plurality of vacant pixel value storage locations being adjacent the pixel value storage location of each pixel in each row of the input image associated with a number of the predetermined value; calculation means coupled to said input register for generating a gray scale value for each vacant pixel storage location as a function of neighboring pixel values; and means for outputting an enlarged image, said enlarged image comprising ordered rows and columns of pixels including all of said input pixel values and said calculated pixel values.

Claim 3

The apparatus of claim 1 further comprising an image end detecting means coupled to said means for inserting, the image end detecting means generating an error signal when a certain condition is met.

Claim 4

The apparatus of claim 1 further comprising an output register means for outputting an enlarged row of pixel values and an inserted row of pixel values, the output register means being coupled to the calculation means and the means for leaving.

Claim 5

Apparatus for enlarging by a given factor of scale a gray scale input image having ordered rows and columns of digitized picture elements (pixels), each said pixel of said input image having a gray scale value, the apparatus comprising: an input register for receiving gray scale pixel values of the input image; a scale factor input register for receiving the given factor of scale; means coupled to the scale factor input register for generating an ordered sequence of numbers as a function of the given factor of scale; means for associating one of said ordered sequence of numbers with each pixel and each row of the input image; means for leaving a vacant pixel value storage location between received pixel values of the input image, said vacant pixel value storage location being adjacent the pixel value storage location of each pixel associated with a number of a predetermined value and for leaving a plurality of vacant pixel storage locations between received pixels of the input image, said vacant pixel value storage locations being adjacent the pixel value storage location of each pixel in each row of the input image associated with a number of the predetermined value, the means for leaving being coupled to the input register and the means for generating; calculation means coupled to said input register for calculating a gray scale value for each vacant pixel value storage location as a function of neighboring pixel values; means for counting rows and columns of pixels, the means for counting being coupled to the means for generating and the means for leaving; means for storing selected pixel values for use by the calculation means, the means for storing being coupled to the input register and the means for leaving; an output register for outputting an enlarged row of pixel values and an inserted row of pixel values, the output register being coupled to the calculation means and the means for leaving; means for outputting an enlarged image, said enlarged image comprising rows and columns of pixels including all of said input pixel values and said calculated pixel values; and image end detecting means coupled to the means for leaving for generating an error signal when a certain condition is met.

Claim 6

Apparatus for enlarging by a given factor of scale a gray scale input image having ordered rows and columns of digitized picture elements (pixels), each said pixel of said input image having a gray scale value, the apparatus comprising: an input register for receiving gray scale pixel values of the input image; a scale factor input register for receiving the given factor of scale; means coupled to the scale factor input register for generating an ordered sequence of numbers as a function of the given factor of scale; means for associating one of said ordered sequence of numbers with each pixel and each row of the input image; means for leaving a vacant pixel value storage location between received pixel values of the input image, said vacant pixel value storage location being adjacent the pixel value storage location of each pixel associated with a number of a predetermined value and for leaving a plurality of vacant pixel storage locations between received pixels of the input image, said vacant pixel value storage locations being adjacent the pixel value storage location of each pixel in each row of the input image associated with a number of the predetermined value, the means for leaving being coupled to the input register and the means for generating; calculation means coupled to said input register for calculating a gray scale value for each vacant pixel value storage location as a function of neighboring pixel values; means for counting rows and columns of pixels, the means for counting being coupled to the means for generating and the means for leaving; means for storing selected pixel values for use by the calculation means, the means for storing being coupled to the input register and the means for leaving; an output register for outputting an enlarged row of pixel values and an inserted row of pixel values, the output register being coupled to the calculation means and the means for leaving; means for outputting an enlarged image, said enlarged image comprising rows and columns of pixels including all of said input pixel values and said calculated pixel values; and image end detecting means coupled to the means for leaving for generating an error signal when a certain condition is met.

Claim 9

The method of claim 5 wherein the value for a vacant pixel storage location is calculated by adding together values of two neighboring pixels adjacent said vacant pixel in the same row and dividing the sum by 2.

Claim 10

The method of claim 6 wherein the value for a vacant pixel storage location in an inserted row is calculated by dividing a sum of values of two neighboring pixels adjacent the inserted row in the same column by 2.

Claim 11

The method of claim 6 wherein the value for a vacant pixel storage location in an inserted row and column is calculated by a weighted averaging of at least three adjacent pixel values.

Claim 12

The method of claim 6 wherein any fractional value obtained is rounded towards a darkest gray level value.

Claim 13

The method of claim 7 wherein any fractional value obtained is rounded toward a darkest gray level value.

Claim 14

The method of claim 5 wherein any fractional value obtained is rounded towards a darkest gray level value.

Claim 15

The method of claim 5 wherein said scale factor is expressible as a ratio of integers between 1:1 and 2:1.

Claim 16

The method of claim 5 wherein said ordered sequence of numbers is calculated for a number of scale factors and stored in a look-up table.

Claim 17

The method of claim 5 wherein said ordered sequence of numbers consists of ones and twos.

Claim 18

The method of claim 14 wherein the predetermined value is two.