Apparatus and method for processing images, recording medium, and program

• US 20040223662A1
• Filed: 02/18/2004
• Published: 11/11/2004
• Est. Priority Date: 03/18/2003
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Koda, Natsuo, Urano, Izumi
• Granted Patent: US 7,362,900 B2
• Time in Patent Office: Days
• US Class Current: 382/299
• CPC Class Codes: G06T 3/403 Edge-driven scaling; Edge-based scaling
• CPC Class Codes: G06T 3/4084 in the transform domain, e.g. fast Fourier transform [FFT] domain scaling

Abstract

An image input section outputs the size of an image to a division-number setting section and outputs the image to an edge enhancing section, which enhances the edges of the image. An edge extracting section extracts the edges, an edge evaluating section checks whether each pixel belongs to an edge, and an edge counting section outputs the frequencies of the edges. A DFT section applies a Fourier transform to the edge frequencies which are output as power spectra, and a peak extracting section outputs the spatial frequencies at the peaks of the power spectra. A division-number setting section determines the number of divisions from the spatial frequencies. An image dividing section divides the image into the determined number of blocks and a colored-image output section assigns a particular pixel value to all pixels in each of the blocks.

Claims

1. An image processing apparatus comprising:

edge-extracting means for extracting edges of an input image composed of pixels in a matrix;

period-detecting means for detecting the periods of the edges;

dividing means for dividing the input image into blocks according to the periods of the edges; and

pixel-value converting means for converting the pixel values of all pixels in each of the blocks to a predetermined pixel value.

2. The image processing apparatus according to claim 1, further comprising:

frequency-detecting means for detecting the frequencies of pixels belonging to the edges extracted by the edge-extracting means in each of the horizontal and vertical directions of the matrix,

wherein the period-detecting means detects the periods of the edges in each of the horizontal and vertical directions of the matrix based on the frequencies of the pixels.

3. The image processing apparatus according to claim 1, further comprising:

discrete Fourier transforming means for applying a discrete Fourier transform to the frequencies of the pixels belonging to the edges in each of the horizontal and vertical directions to produce respective power spectra; and

peak-detecting means for detecting the spatial frequency at the peak in each of the power spectra,

wherein the period-detecting means detects the periods of the edges based on the spatial frequencies at the peaks.

4. A method for processing an image, the method comprising:

an edge-extracting step of extracting edges of an input image composed of pixels in a matrix;

a period-detecting step of detecting the periods of the edges;

a dividing step of dividing the input image into blocks according to the periods of the edges; and

a pixel-value converting step of converting the pixel values of all pixels in each of the blocks to a predetermined pixel value.

5. A recording medium containing a computer-readable program, the program comprising:

an edge-extracting step of extracting edges of an input image composed of pixels in a matrix;

a period-detecting step of detecting the periods of the edges;

a dividing step of dividing the input image into blocks according to the periods of the edges; and

a pixel-value converting step of converting the pixel values of all pixels in each of the blocks to a predetermined pixel value.

6. A computer-readable program comprising code to execute a method comprising:

an edge-extracting step of extracting edges of an input image composed of pixels in a matrix;

a period-detecting step of detecting the periods of the edges;

a dividing step of dividing the input image into blocks according to the periods of the edges; and

a pixel-value converting step of converting the pixel values of all pixels in each of the blocks to a predetermined pixel value.