Image pickup apparatus with interpolation and edge enhancement of pickup signal varying with zoom magnification

• US 5,838,371 A
• Filed: 07/14/1997
• Issued: 11/17/1998
• Est. Priority Date: 03/05/1993
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Hirose, Hisataka, Kondo, Toshiaki, Matsui, Izumi
• Primary Examiner(s): KOSTAK, VICTOR R
• Application Number:
  US08/892,342
• Time in Patent Office: 491 Days
• Field of Search: 348/240, 348/231, 348/233, 348/252, 348/71, 348/222, 348/253
• US Class Current: 348/240.2
• CPC Class Codes: G06T 3/403 Edge-driven scaling; Edge-based scaling
• CPC Class Codes: H04N 23/843 Demosaicing, e.g. interpolating colour pixel values
• CPC Class Codes: H04N 5/142 Edging; Contouring
• CPC Class Codes: H04N 5/2628 Alteration of picture size, shape, position or orientation, e.g. zooming, rotation, rolling, perspective, translation

Abstract

The amount of edge enhancement outputted from an amount-of-edge-enhancement computing circuit is determined on the basis of the degree of sharpness of the edge independently of a zoom magnification. In the meantime, in an enhancement coefficient computing circuit, an enhancement coefficient according to the zoom magnification is computed. In a multiplier, the output from the amount-of-edge-enhancement computing circuit (the amount of edge enhancement) is multiplied by the output from the enhancement coefficient computing circuit (the enhancement coefficient). The resultant amount of edge correction is outputted from the multiplier. Accordingly, the amount of edge correction outputted from the multiplier takes a value according to the zoom magnification. According to this arrangement, enhancement processing which does not bring about overcorrection or unprocessing can be applied to the edge portion of an image enlarged by electronic zoom. In consequence, it is possible to enhance the apparent resolution of the image enlarged by electronic zoom.

Claims

1. An image pickup apparatus comprising:

a) image pickup means;

b) memory means for storing an output of said image pickup means;

c) zoom magnification control means for varying zoom magnification of an output of said memory means;

d) interpolating means for interpolating the signal outputted from said memory means, said interpolating means varies interpolation of said memory means output signal on the basis of said zoom magnification controlled by said zoom magnification control means;

e) edge enhancing means for applying edge enhancing to a signal outputted from said interpolating means; and

f) controlling means for varying edge enhancement by said edge enhancing means in accordance with said zoom magnification controlled by said zoom magnification control means.

2. An image pickup apparatus according to claim 1, further comprising timing control means for timing for writing in the memory and timing for read out from the memory.

3. An image pickup apparatus according to claim 2, wherein said timing means controls the timing for writing in the memory and the timing for read out from the memory on the basis of a control signal from the zoom magnification control means.

4. An image pickup apparatus, comprising:

a) image pickup means;

b) memory means for storing an output of said image pickup means;

c) magnification control means for varying magnification of an output of said memory means;

d) interpolating means for interpolating the signal outputted from said memory means;

e) edge enhancing means for applying edge enhancing to a signal outputted from said interpolating means; and

f) controlling means for varying edge enhancement by said edge enhancing means and interpolation characteristics of the output signal of said memory means by said interpolating means in accordance with magnification controlled by said magnification control means.

5. An image pickup apparatus according to claim 4, further comprising timing control means for timing for writing in the memory and timing for read out from the memory.

6. An image pickup apparatus according to claim 5, wherein said timing means controls the timing for writing in the memory and the timing for read out from the memory on the basis of a control signal from the magnification control means.