Method for scaling and cropping images for television display
A method of processing an image for display on a television screen is described. Unlike conventional method which over-expands the image, the method described herein crops the image (optionally) and scales it to fit the native resolution of the display screen without over-expanding the image. The method includes the steps of receiving a source television image having a native image resolution, scaling the source television image using a scaling ratio to produce a scaled television image having a resolution equal to or less than the native screen resolution in both a vertical and a horizontal direction, and displaying the scaled television image on the television screen. The scaling ratio may be the same or different in the vertical and horizontal directions.
1 . A method of processing an image for display on a television screen having a native screen resolution, comprising:
receiving a source television image having a native image resolution;
scaling the source television image using a scaling ratio to produce a scaled television image having a resolution equal to or less than the native screen resolution in both a vertical and a horizontal direction; and
displaying the scaled television image on the television screen.
2 . The method of claim 1 , wherein the scaling ratio has the same value in the vertical and horizontal directions.
3 . The method of claim 1 , wherein the scaling ratio has different values in the vertical and horizontal directions.
4 . The method of claim 1 , wherein the scaling ratio has constant values across the television screen in the vertical and horizontal direction.
5 . The method of claim 1 , wherein the scaling ratio has variable values across the television screen in the vertical or horizontal direction.
6 . The method of claim 1 , wherein the resolution of the scaled television image is equal to the native screen resolution in a vertical direction.
7 . The method of claim 1 , wherein the resolution of the scaled television image is equal to the native screen resolution in the horizontal direction.
8 . The method of claim 1 , wherein the scaling ratio is such that the resolution of the scaled television image is equal to the native screen resolution in both a vertical and a horizontal direction.
9 . The method of claim 1 , wherein the native image resolution of the source television image is NTSC, PAL, or SECAM compliant.
10 . The method of claim 1 , wherein the native image resolution of the source television image is 1280×720 pixels.
11 . The method of claim 1 , wherein the native image resolution of the source television image is 1920×1080 pixels.
12 . The method of claim 1 , further comprising cropping the source television image before scaling it.
13 . The method of claim 12 , wherein cropping comprises removing the same number of lines from a top and a bottom edge of the source television image, and removing same number of lines from a left and a right edge of the source television image.
14 . The method of claim 12 , wherein cropping comprises removing different numbers of lines from a top and a bottom edge of the source television image, or removing different numbers of lines from a left and a right edge of the source television image.
15 . A method of processing an image for display on a television screen having a native screen resolution, comprising:
receiving a source television image having a native image resolution;
cropping the source television image by removing one or more lines from one or more of a top, a bottom, a left and a right edge of the source television image;
scaling the cropped source television image using a scaling ratio to produce a scaled television image; and
displaying the scaled television image on the television screen.
16 . The method of claim 15 , wherein the cropping step removes the same number of lines from a top and a bottom edge of the source television image, and removing the same number of lines from a left and a right edge of the source television image.
17 . The method of claim 15 , wherein cropping comprises removing different numbers of lines from a top and a bottom edge of the source television image, or removing different numbers of lines from a left and a right edge of the source television image.