Method and apparatus for expanding image data

• US 6,584,237 B1
• Filed: 08/22/2000
• Issued: 06/24/2003
• Est. Priority Date: 08/23/1999
• Status: Expired due to Term

• Current Assignee: PENTAX RICOH IMAGING COMPANY, LTD.
• Original Assignee: Pentax Corporation (Hoya Corporation)
• Inventors: Abe, Nobuaki
• Primary Examiner(s): Tran, Phuoc
• Assistant Examiner(s): Alavi, Amir
• Application Number:
  US09/642,813
• Time in Patent Office: 1,036 Days
• Field of Search: 382/184, 382/233, 382/287, 382/295, 382/296, 382/297, 382/298, 382/299, 382/300, 345/648, 345/659, 345/660, 345/671, 345/672, 345/677, 348/449, 348/561, 348/581, 348/583, 348/704, 358/428, 358/451, 358/488, 358/525, 708/203, 708/208, 708/290, 250/557
• US Class Current: 382/299
• CPC Class Codes: G06T 3/4007 based on interpolation, e.g. bilinear interpolation image demosaicing G06T3/4015; edge-driven or edge-based scaling G06T3/403
• CPC Class Codes: H04N 5/2628 Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation

Abstract

An expanded-image generating apparatus is provided for original image data, in which a plurality of pixels is arranged in a matrix, so as to obtain expanded-image data partitioned into a plurality of blocks, each of which is composed of a plurality of pixels When the magnifying power regarding at least one of a direction along width and a direction along length in the original image data is set, a pixel arranging processor arranges each pixel in the original image data at a position corresponding to a center position of each of the plurality of blocks in accordance with the magnifying power. The expanded-image data corresponding to the magnifying power is generated at pixel generating positions corresponding to the each block by applying a fluency transform to each pixel in the original image data at the position. When the magnifying power is odd numbered, a shifting processor shifts said pixel generating positions relative to each corresponding pixel of said original image data by a shifting-amount corresponding to said magnifying power such that each arranged pixel of said original image data is off-center with respect to said plurality of blocks.

Claims

1. An apparatus for expanding original image data, in which a plurality of pixels is arranged in a matrix, so as to obtain expanded-image data partitioned into a plurality of blocks, each of which is composed of a plurality of pixels, said apparatus comprising:

a magnifying power setting processor that sets a magnifying power regarding at least one of a first direction along a width and a second direction along a length in said original image data;

a pixel arranger that arranges each pixel in said original image data at a position corresponding to a center position of each of said plurality of blocks in accordance with said magnifying power;

an expanded-image generating processor that generates said expanded-image data corresponding to said magnifying power by applying a fluency transform to each arranged pixel in said original image data, said plurality of pixels in each block being generated at pixel generating positions;

a magnifying power inspector that inspects whether said magnifying power is odd numbered; and

a shifting processor that shifts said pixel generating positions relative to each corresponding pixel of said original image data by a shifting-amount corresponding to said magnifying power such that each arranged pixel of said original image data is off-center with respect to said plurality of blocks, when said magnifying power is the odd numbered.

2. The apparatus according to claim 1, wherein said expanded-image generating processor applies said fluency transform, which is expressed by the following formula, to each pixel in said original image data:

$f<br><br>\left(t\right)=\left(1/2<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\pi <br><br>}\right)<br><br>{\int <br><br>}_{-\mathrm{\pi <br><br>}}^{\mathrm{\pi <br><br>}}<br><br>{F<br><br>\left(u\right)}_{\left[m_o\right]}<br><br>\mathrm{\phi <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(t,u\right)<br><br>\text{\hspace{1em}<br><br>}<br><br><br><br>u$

note that, $\begin{array}{c}{\hspace{0.17em}<br><br>}_{\left[m_o\right]}<br><br>\mathrm{\phi <br><br>}<br><br>\left(t,u\right)=\text{\hspace{1em}<br><br>}<br><br>\left(1/2<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\pi <br><br>}\right)<br><br>{\int <br><br>}_{-\mathrm{\infty <br><br>}}^{\mathrm{\infty <br><br>}}<br><br>\left\{\underset{p=-\mathrm{\infty <br><br>}}{\overset{\mathrm{\infty <br><br>}}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\delta <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>\left(\mathrm{\omega <br><br>}-u+2<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\pi <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>p\right)\right\}\times <br><br>\\ \text{\hspace{1em}<br><br>}<br><br>{\left\{\underset{q=-\mathrm{\infty <br><br>}}{\overset{\mathrm{\infty <br><br>}}{\sum <br><br>}}<br><br>\text{\hspace{1em}<br><br>}<br><br>{\left(1-q<br><br>\left(2<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\pi <br><br>}/\mathrm{\omega <br><br>}\right)\right)}^{-2<br><br>m}\right\}}^{-1/2}\times <br><br>\exp <br><br>\left(\mathrm{<br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>\mathrm{\omega <br><br>}<br><br>\text{\hspace{1em}<br><br>}<br><br>t\right)<br><br><br><br>\mathrm{\omega <br><br>}\end{array}$

where F(u) corresponds to each pixel value of said original image data, f(t) is output values of said fluency transform, φ

(t,u) is a fluency function defined by a fluency function space ^mS, m (=1,2,3, . . . ) is a parameter indicating a differentiability.

3. The apparatus according to claim 2, wherein said expanded-image generating processor obtains said expanded-image data by adding said output values f(t) corresponding to pixel position in each of said plurality of blocks.

4. The apparatus according to claim 3, wherein said expanded-image generating processor applies said fluency transform along said first direction so that pixels aligned along said first direction are generated, and then applies said fluency transform along said second direction to said pixels aligned along said first direction.

5. The apparatus according to claim 4, wherein said shifting processor shifts said pixel generating positions along said first direction such that each arranged pixel of said original image data is between each corresponding pixel generating position and its adjacent pixel generating position when executing said fluency transform along said first direction, and shifts said pixel generating positions along said second direction such that each of said pixels aligned along said first direction is between each corresponding pixel generating position and its adjacent pixel generating position along said second direction when executing said fluency transform along said second direction.

6. The apparatus according to claim 4, wherein a pixel number along said width direction and a pixel number along said length direction in each of said plurality of blocks is the same, and said magnifying power indicates a ratio of a pixel number along said first/second direction in said expanded-image data to a pixel number along said first/second direction in said original image data.

7. The apparatus according to claim 6, wherein said shifting processor shifts by “

M/2Z”

along said first and second direction respectively when it is supposed that a length/width of each block is represented by “

M”

, and said magnifying power is represented by “

Z”

.

8. A method for expanding original image data, in which a plurality of pixels is arranged in a matrix, so as to obtain expanded-image data partitioned into a plurality of blocks, each of which is composed of a plurality of pixels, said method comprising:

a first step that sets a magnifying power regarding at least one of a first direction along a width and a second direction along a length in said original image data;

a second step that arranges each pixel in said original image data at a position corresponding to a center position of each of said plurality of blocks in accordance with said magnifying power;

a third step that inspects whether said magnifying power is odd numbered;

a fourth step that shifts pixel generating positions relative to each corresponding pixel of said original image data by a shifting-amount corresponding to said magnifying power such that each arranged pixel of said original image data is off-center with respect to said plurality of blocks, when said magnifying power is the odd numbered; and

a fifth step that generates said expanded-image data corresponding to said magnifying power by applying a fluency transform to each pixel in said original image data, each pixel in said original image data being subjected to said fluency transform at one of the position corresponding to said center position of each block and an off-center position with respect to each block.

9. A memory medium that stores a program for expanding original image data comprising:

a first step that sets a magnifying power regarding at least one of a direction along a width and a direction along length in said original image data;

a second step that arranges each pixel in said original image data at a position corresponding to a center position of each of said plurality of blocks in accordance with said magnifying power;

a third step that inspects whether said magnifying power is odd numbered;

a fourth step that shifts pixel generating positions relative to each corresponding pixel of said original image data by a shifting-amount corresponding to said magnifying power, such that each arranged pixel of said original image data is off-center with respect to said plurality of blocks, when said magnifying power is the odd numbered; and

a fifth step that generates said expanded-image data corresponding to said magnifying power by applying a fluency transform to each pixel in said original image data, each pixel in said original image data being subjected to said fluency transform at one of the position corresponding to said center position of each block and an off-center position with respect to each block.