KR100936354B1 - Apparatus and method for providing digital zoom - Google Patents

Abstract

Embodiments are directed to an apparatus and method for providing digital zoom with enhanced resolution.

An apparatus for providing digital zoom according to an embodiment includes an optical system for generating an optical image in which the central area is enlarged compared to the peripheral area without intentional barrel distortion and pincushion distortion; An imaging module for converting the optical image into a digital image having a first resolution corresponding to the central area having a higher resolution than a second area corresponding to the peripheral area; And an image processing module that performs cropping, rescaling, and distortion correction of the digital image.

Digital zoom

Description

Device and method for providing digital zoom {APPARATUS AND METHOD FOR PROVIDING DIGITAL ZOOM}

Embodiments are directed to an apparatus and method for providing digital zoom with enhanced resolution.

Portable electronic imaging devices such as digital cameras or digital video cameras provide a zoom function. The zoom function is provided through the use of a zoom lens or by cropping and rescaling a digital image.

Typically, a zoom function provided by using a zoom lens is called optical zoom, and a zoom function provided through a process of cropping and rescaling a digital image is called digital zoom. The digital zoom has an advantage that can be easily applied to the electronic imaging device at low cost.

The digital zoom provides an image of a larger size by using the existing pixel information to predict the added pixel information.

The simplest method of predicting pixel information to provide digital zoom function is to duplicate the pixel values of neighboring neighboring pixels, and in a more complicated way, the intermediate pixel value from the information of the neighboring neighboring pixels. There is a way to use interpolation by creating a value. These techniques are known and used in various image processing methods.

However, even if the electronic imaging device has a relatively high resolution, the resolution of the image at a high zoom magnification when using a rescaling method, in particular, by replicating pixel values to provide a digital zoom function. Deterioration occurs.

If a lens that provides a higher resolution or an optical zoom lens is used to compensate for the degradation of an image due to digital zoom, the weight, cost, and size of the electronic imaging device increase. There is.

Meanwhile, US Patent No. 7,098,949 discloses an Apparatus and method for improved-resolution digital zoom in a portable electronic imaging device.

The U.S. Patent (US 7,098,949) uses barrel distortion to generate a higher quality digital zoom image from the original image, and uses the digital zoom function through simple cropping and rescaling processes. Provided are an apparatus and a method for providing the same.

Specifically, the US patent US 7,098,949 uses a lens with radial symmetry distortion, which has a higher magnification in the central region than the peripheral region, thereby forming an optical image of barrel distortion. An apparatus and method for providing a zoom function using a lens are described.

A photographic object represented by the uniform grid pattern shown in FIG. 1 is generated by the lens with the radial symmetrical distortion into an optical image having barrel distortion as shown in FIG. 2.

Meanwhile, the rescaling technique may be appropriately applied in the central region of the optical image, but may not be appropriately applied since the intermediate pixel is not rectangular in the peripheral region of the optical image. Thus, the rescaling technique must be modified.

Such a modification of the rescaling technique necessarily has a problem of causing a complexity of calculation.

An embodiment provides an apparatus and method for providing a digital zoom function.

Embodiments provide an apparatus and method for providing a digital zoom function with enhanced resolution.

An apparatus for providing digital zoom according to an embodiment includes an optical system for generating an optical image in which the central area is enlarged compared to the peripheral area without intentional barrel distortion and pincushion distortion; An imaging module for converting the optical image into a digital image having a first resolution corresponding to the central area having a higher resolution than a second area corresponding to the peripheral area; And an image processing module that performs cropping, rescaling, and distortion correction of the digital image.

An apparatus for providing digital zoom according to an embodiment includes an optical system including at least one cylindrical lens, the optical system generating an optical image with a central area enlarged relative to a peripheral area; An imaging module for converting the optical image into a digital image having a first resolution corresponding to the central area having a higher resolution than a second area corresponding to the peripheral area; And an image processing module that performs cropping, rescaling, and distortion correction of the digital image.

An apparatus for providing digital zoom according to an embodiment includes an optical system including at least one lens having a line focus, the optical system generating an optical image in which a central area is enlarged relative to a peripheral area; An imaging module for converting the optical image into a digital image having a first resolution corresponding to the central area having a higher resolution than a second area corresponding to the peripheral area; And an image processing module that performs cropping, rescaling, and distortion correction of the digital image.

According to an embodiment, there is provided a method of providing a digital zoom, the method including: generating an optical image in which a central area is enlarged relative to a peripheral area without intentional barrel distortion and pincushion distortion; Converting the optical image into a digital image having a first resolution corresponding to the center area having a higher resolution than a second area corresponding to the peripheral area; Generating a digital image cropped in the first region; Performing rescaling and distortion correction on the cropped digital image.

An apparatus for providing digital zoom according to an embodiment includes an optical system for generating an optical image in which a central area is enlarged compared to a peripheral area based on a first direction; An imaging module for converting the optical image into a digital image having a first resolution corresponding to the central area having a higher resolution than a second area corresponding to the peripheral area; And an image processing module that performs cropping, rescaling, and distortion correction of the digital image.

Embodiments may provide an apparatus and method for providing an enhanced digital zoom function.

Hereinafter, an apparatus and method for providing a digital zoom function according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Lenses whose magnification is higher in the central region than in the peripheral region are used to accept a distorted image. Such distorted images can be corrected by known mathematical methods. For example, Korean Patent Publication No. 10-0456632 discloses an image-based lens distortion correction apparatus and method, and Korean Patent Publication No. 10-0744937 discloses a lens distortion correction method.

However, the image of correcting the distorted image is deteriorated in quality compared to the image without distortion, which is received using the lens without distortion. In particular, the degradation of the image is more apparent in the peripheral area of the image, since the peripheral area of the image must be enlarged through some known mathematical method of correction. However, in most cases, the surrounding area of the image does not have a big influence on visual perception.

Meanwhile, when the distorted image is digitally processed, the first region, which is the central region of the image corresponding to the central region of the lens, has a higher resolution than the second region, which is the peripheral region of the image corresponding to the peripheral region of the lens. .

When performing the zoom operation on the distorted image, since the center region of the image has a relatively high resolution, magnification of the center region of the image may be performed without degrading the resolution or with the deterioration of the minimum resolution. Can be.

3 is a block diagram illustrating an apparatus and method for providing a digital zoom according to an embodiment.

The electronic imaging device described in the embodiment includes an electronic device for digitizing an optical image, such as a digital camera or a digital video camera.

Referring to FIG. 3, the electronic imaging apparatus according to the embodiment includes an optical system 11, an imaging module 12, an image processing module 13, and a display unit. 15, a memory 14 is included.

The optical system 11 produces an optical image. For example, the optical system 11 provides an enlarged optical image compared to a second region in which the first region in the center region is the peripheral region without intentional barrel distortion and pincushion distortion.

The optical system 11 comprises at least one cylindrical lens with a predefined distortion property. The optical system 11 will be described later in more detail.

The imaging module 12 converts the optical image generated by the optical system 11 into a digital image. For example, the imaging module 12 may be an optical sensor or analog-to-digital converter (A / D) based on known Charge-Coupled-Device (CCD) or Complementary Metal Oxide Semiconductor (CMOS) technology. , A gain control, and a digital signal processor (DSP).

The image processing module 13 is connected to the imaging module 12, the memory 14, and the display unit 15 to provide a digital image in which a zoom function is performed. That is, the image processing module 13 performs cropping, rescaling, and distortion correction of the digital image so that the image is output to the display unit 15.

Here, an image that only performs distortion correction without rescaling is similar to an image received by lenses without distortion.

In addition, the rescaling and distortion correction may be performed simultaneously, or one may be performed first and the other may be performed later.

The memory 14 may include random access memory (RAM) and non-volatile memory (RAM), and the memory 14 may store digital zoom firmware or photographed digital images. Can be.

The digital zoom firmware includes software programmed with a digital zoom function, a distortion correction function, and a rescaling function.

The digital zoom function crops the digital image in the center region of the image having a higher resolution than the peripheral region of the image according to the required digital zoom magnification. The distortion correction function corrects the distortion caused by the lens. The rescaling function enlarges the cropped image by methods such as replication or interpolation of pixel values.

For example, the rescaling function can be used to provide a preview function of a digitally zoomed scene before the final image is taken by the user.

The display unit 15 provides the photographed digital image or the preview image before the photographing to the user.

4 and 5 show that a photographic object represented by a uniform grid pattern is represented by an optical image by the optical system according to the embodiment.

The optical system 11 comprises a plurality of lenses. In particular, the optical system 11 comprises at least one cylindrical lens, in which an optical image by an optical system including one cylindrical lens is shown, and in FIG. An optical image is shown by an optical system incorporating a cylindrical lens.

Optical system 11 according to an embodiment provides an optical image free of intentional barrel distortion and pincushion distortion.

As can be seen in FIG. 4, the central region is enlarged relative to the peripheral region relative to the peripheral region in the horizontal direction without the intentional barrel distortion and pincushion distortion of the optical system 11. do. Although not shown, the optical system 11 may provide an optical image in which the central area is enlarged compared to the peripheral area with respect to the vertical direction.

Also, as can be seen in FIG. 5, the central region is enlarged relative to the peripheral region relative to the horizontal and vertical directions without the intentional barrel distortion and pincushion distortion of the optical system 11. Provides an optical image.

6 is a view illustrating a lens included in an optical system according to an embodiment, and FIG. 7 is a view illustrating a cross section of the lens.

Lens 20 according to the embodiment is formed in a cylindrical (cylindrical) shape, a portion is cut. The lens 20 has a predefined distortion property, and its shape may be modified according to the distortion property.

The lens 20 includes a curved surface 22 and a plane 23 symmetric with respect to the virtual vertical symmetry plane 21.

The lens 20 has the same shape in all parallel cross sections cut along the vertical symmetry plane 21. The cross section of the lens shown in FIG. 7 is one of the cross sections cut along the vertical symmetry plane 21. In addition, the vertical symmetry plane 21 in the cross section appears as an axis of symmetry.

In addition, in general electronic imaging devices, only convex or concave circular lenses are used on at least one surface. These circular lenses have a focal point or real focal point form. In contrast, in the exemplary embodiment, the lens 20 may be formed to have a line focus contrasted to the point focus.

8 illustrates two cylindrical lenses.

Each lens 20 shown in FIG. 8 is designed as described with reference to FIGS. 6 and 7, except that the vertical symmetry planes 21 are orthogonal to each other.

In addition, each lens 20 may be formed to have a line focus, and the two line focuses are orthogonal to each other.

The lens 20 according to the embodiment is formed in a rectangular shape in a plane perpendicular to the optical axis, but the shape may be modified according to the design of the optical system 11.

The lens 20 according to the embodiment is designed such that the central region has a higher magnification than the peripheral region with respect to the first direction. If the two lenses 20 are arranged to intersect, the two lenses are designed such that the central area is higher in magnification than the peripheral area in the first direction and in the second direction orthogonal to the first direction.

As such, the optical system 11 according to the embodiment generates an optical image of a shape corresponding to the rectangular grid cells shown in FIGS. 4 and 5, which is a faster and simpler algorithm for image rescaling. To use.

According to another exemplary embodiment, the image processing module 13 may be connected to the imaging module 12, the memory 14, the display unit 15, and an external processor (not shown) to communicate.

In this case, the external processor may function to perform rescaling and distortion correction.

1 shows a photographic object in a uniform grid pattern;

FIG. 2 shows that the object to be captured shown in FIG. 1 is created as an optical image with barrel distortion by a lens with radial symmetry distortion. FIG.

3 is a block diagram illustrating an apparatus and method for providing digital zoom according to an embodiment.

4 and 5 show that an object captured in a uniform grid pattern is represented by an optical image by an optical system according to an embodiment.

6 illustrates a lens included in an optical system according to an embodiment.

7 shows a cross section of a lens;

8 illustrates two cylindrical lenses.

Claims (19)

An optical system for generating an optical image in which the central region is enlarged relative to the peripheral region without intentional barrel distortion and pincushion distortion; An imaging module for converting the optical image into a digital image having a first resolution corresponding to the central area having a higher resolution than a second area corresponding to the peripheral area; And And an image processing module that performs cropping, rescaling, and distortion correction of the digital image. The method of claim 1, The optical system provides a digital zoom for generating an optical image in which the central area is enlarged relative to the peripheral area with respect to the first direction. The method of claim 1, And the optical system provides a digital zoom for generating an optical image in which a central area is enlarged relative to a peripheral area with respect to a first direction and a second direction orthogonal to the first direction. The method of claim 1, And a memory storing firmware for performing a cropping function, a rescaling function, and a distortion correction function of the digital image. The method of claim 1, And a display unit for displaying the digital image output from the image processing module. An optical system comprising at least one cylindrical lens, the optical system generating an optical image in which the central region is enlarged relative to the peripheral region without intentional barrel distortion and pincushion distortion; An imaging module for converting the optical image into a digital image having a first resolution corresponding to the central area having a higher resolution than a second area corresponding to the peripheral area; And And an image processing module that performs cropping, rescaling, and distortion correction of the digital image. The method of claim 6, And the cylindrical lens includes a curved surface and a plane symmetrical with respect to a vertical symmetry plane. The method of claim 6, And said cylindrical lens provides a digital zoom having the same shape in cross sections parallel to each other cut along a vertical symmetry plane. The method of claim 6, The cylindrical lens includes two, each cylindrical lens has a curved surface and a plane symmetrical with respect to the vertical symmetry plane and the parallel cross-sections cut along the vertical symmetry plane have the same shape, each cylinder Vertical symmetry plane of the lens type is provided with a digital zoom arranged to be orthogonal to each other. The method of claim 6, The cylindrical lens includes a curved surface and a plane symmetrical with respect to the vertical symmetry plane, the plane is perpendicular to the optical axis and provides a digital zoom having a rectangular shape. An optical system comprising at least one lens having a line focus, wherein the optical system produces an optical image in which the central region is enlarged relative to the peripheral region without intentional barrel distortion and pincushion distortion; An imaging module for converting the optical image into a digital image having a first resolution corresponding to the central area having a higher resolution than a second area corresponding to the peripheral area; And And an image processing module that performs cropping, rescaling, and distortion correction of the digital image. The method of claim 11, And at least two lenses having the line focus, wherein the line focus of each lens is orthogonal to each other. delete Generating an optical image in which the central region is enlarged relative to the peripheral region without intentional barrel distortion and pincushion distortion; Converting the optical image into a digital image having a first resolution corresponding to the center area having a higher resolution than a second area corresponding to the peripheral area; And Generating a digital image cropped in the first region; Performing rescaling and distortion correction on the cropped digital image. The method of claim 14, Wherein said rescaling and distortion correction are performed simultaneously. The method of claim 14, And any one of said rescaling and distortion correction is performed first and then the other. An optical system for generating an optical image in which the central region is enlarged relative to the peripheral region relative to the horizontal or vertical direction without intentional barrel distortion and pincushion distortion; An imaging module for converting the optical image into a digital image having a first resolution corresponding to the central area having a higher resolution than a second area corresponding to the peripheral area; And And an image processing module that performs cropping, rescaling, and distortion correction of the digital image. delete An optical system for generating an optical image in which the central region is enlarged relative to the peripheral region relative to the horizontal and vertical directions without intentional barrel distortion and pincushion distortion; An imaging module for converting the optical image into a digital image having a first resolution corresponding to the central area having a higher resolution than a second area corresponding to the peripheral area; And And an image processing module that performs cropping, rescaling, and distortion correction of the digital image.

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