KR20040073722A - Apparatus and Method for improving quality of picture in mobile terminal attatched digital camera - Google Patents

Abstract

PURPOSE: A method for improving picture quality of a mobile terminal where a digital camera is mounted is provided to compensate for non-uniformity of picture quality with regards to each pixel, and to display non-uniformity compensated images, thereby obtaining a better image quality. CONSTITUTION: When a camera is operated(S300), a mobile terminal measures brightness of each pixel for an image(S302). The mobile terminal extracts brightness of a central pixel(S304), and finds relative sensitivity with regards to each pixel of the image(S306). The mobile terminal obtains a compensation value for compensating a relative sensitivity difference by using the found relative sensitivity(S308). The mobile terminal compensates for non-uniformity of picture quality by using the obtained compensation value(S310). The mobile terminal displays the non-uniformity compensated image on a display(S312).

Description

Apparatus and Method for improving quality of picture in mobile terminal attatched digital camera}

The present invention relates to a method and apparatus for improving image quality of a mobile terminal equipped with a digital camera.

Recently, a mobile communication terminal having a built-in or removable external digital camera is widely used. According to the mobile communication terminal equipped with such a digital camera, not only voice communication but also video communication can be performed, and the captured image data can be transferred to the mobile communication terminal. It may be stored in the memory of the transfer to a personal computer or transmitted to the mobile communication terminal of another person through the mobile communication terminal.

In the digital camera of such a mobile communication terminal, the digital image data captured from the digital camera can be transmitted to the mobile communication terminal through its connection terminal and displayed on the liquid crystal display of the mobile communication terminal, and at the same time through the computer through the data input / output connector. You can also transfer the files to a variety of operations such as saving, editing and printing.

As the demand of the mobile terminal equipped with the camera is rapidly increasing in recent years, the image quality of the camera has emerged as a very important factor in the selection of the mobile terminal.

In the case of a digital camera developed for a mobile terminal, as the size is downsized, elements that have a great influence on image quality such as lenses and image sensors are inevitably downsized.

With the miniaturization of the lens and the image sensor, the distance between the image sensor and the image becomes shorter, and as a result, the amount of light input to the image sensor decreases as the distance from the center of the sensor decreases.

In other words, the sensitivity of the outside of the screen is lower than that of the center of the screen, which causes an unevenness of image quality.

As a method for overcoming this, the lens of the camera is configured as shown in FIGS. 1A and 1B.

However, in the related art, when a new module is developed, development of a lens suitable for the module is inevitably followed, and thus there is a problem that an increase in cost and a long development period are required.

Accordingly, an object of the present invention is to provide a method and apparatus for improving the image quality of a mobile terminal equipped with a digital camera for improving the uniformity of image quality of the mobile terminal equipped with a digital camera.

1A and 1B are views showing the configuration of a conventional camera lens.

2 is a block diagram schematically illustrating a configuration of an apparatus for improving image quality of a mobile terminal equipped with a digital camera according to an exemplary embodiment of the present invention.

3 is a flowchart illustrating a method of improving image quality of a mobile terminal equipped with a digital camera according to an exemplary embodiment of the present invention.

4 is a flowchart illustrating a method for improving image quality uniformity using a predetermined correction value according to an exemplary embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

200: recording unit 210: signal processing unit

202: size conversion unit 204: format conversion unit

206: sensitivity adjusting unit 220: wireless unit

230: memory 240: display unit

According to an aspect of the present invention to achieve the above object, a signal processing unit for converting the size and format to a desired form for the captured image, and compensates for the image quality unevenness for each pixel of the image, the image quality unevenness compensation The apparatus for improving the image quality of a mobile terminal equipped with a digital camera is provided, including a wireless unit for transmitting the antenna through an antenna, and a display unit displaying an image compensated for the image quality non-uniformity.

The apparatus may further include a memory configured to store an image compensated for the image quality non-uniformity, wherein the memory stores a sensitivity correction value predetermined for each type of mobile terminal, and the signal processing unit uses the stored correction value to display an image quality of the image. Compensate for non-uniformity.

The signal processing unit obtains a relative sensitivity for each pixel by measuring a luminance of each pixel of the image, a size converter for converting the image into a desired size, a format converter for converting the image into a desired format, and obtaining the relative sensitivity. And a sensitivity adjusting unit which obtains a correction value by using the sensitivity and compensates for an image quality non-uniformity of the corresponding image.

The relative sensitivity is quantified by the relative luminance value of the remaining pixels relative to the luminance of the screen center pixel, and the correction value is 1 / relative sensitivity.

According to another aspect of the present invention, after measuring the luminance of each pixel with respect to the image taken by the camera startup, extracting the luminance of the center pixel, and after calculating the relative sensitivity for each remaining pixel, the obtained relative sensitivity And a correction value for correcting the difference in relative sensitivity, using the obtained correction value to compensate for image quality non-uniformity, and displaying an image compensated for the image quality non-uniformity. A method of improving image quality is provided.

According to another aspect of the present invention, after extracting a correction value for each pixel stored in advance with respect to the image photographed by the start of the camera, and using the extracted correction value to compensate for the image quality nonuniformity There is provided a method for improving the image quality of a mobile terminal equipped with a digital camera, characterized in that to display an image compensated for the image quality non-uniformity.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram schematically illustrating a configuration of an apparatus for improving image quality of a mobile terminal equipped with a digital camera according to an exemplary embodiment of the present invention.

Referring to FIG. 2, an apparatus for improving image quality of a mobile terminal equipped with a digital camera includes a photographing unit 200, a signal processing unit 210, a wireless unit 220, a memory 230, and a display unit 240.

The photographing unit 200 captures an image and transmits the image to the signal processing unit 210.

The signal processor 210 converts the image into an image of a desired size and format in order to perform a function such as compression / restore on the image transmitted from the photographing unit 200.

In addition, the signal processor 210 measures the sensitivity of each pixel of the image transmitted from the photographing unit 200 to compensate for the image quality unevenness due to the difference in sensitivity.

The signal processor 210 as described above includes a size converter 202, a format converter 204, and a sensitivity adjuster 206.

The size converter 202 converts the image into a desired size such as VGA, QVGA, and the like, and the format converter 204 converts the image into a desired format such as RGB, YUV, and the like.

The sensitivity adjusting unit 206 measures luminance for each pixel of the corresponding image, and measures relative sensitivity for each pixel. Then, the sensitivity adjusting unit 206 obtains a correction value for correcting the difference in relative sensitivity using the measured relative sensitivity, and then compensates for an image quality non-uniformity of the corresponding image using the obtained correction value.

The wireless unit 220 transmits an image converted by the signal processor 210 to another mobile terminal or receives an image transmitted from another mobile terminal.

The memory 230 stores an image transmitted from the signal processor 210.

According to another aspect of the present invention, the memory 230 stores a predetermined sensitivity correction value for each mobile terminal, so that the signal processor 210 compensates the image quality unevenness of the corresponding image by using the stored correction value.

The display unit 240 displays an image of which image quality non-uniformity is compensated for by the signal processor 210.

Hereinafter, the operation of the image quality improving apparatus of the mobile terminal equipped with the digital camera configured as described above will be described.

The output image of the camera module is converted into an image of a desired size / format through a signal processing unit 210 for performing a function such as image compression / restore, and the converted image is transmitted to another mobile terminal through the wireless unit 220. Or stored in memory 230.

In this case, the signal processor 210 analyzes data output from the photographing unit 200 to measure relative sensitivity. The difference in sensitivity is quantified by the relative luminance value of the remaining pixels with respect to the luminance of the screen center pixel.

The equation for obtaining the relative sensitivity is as in Equation 1.

A correction value for correcting the difference in relative sensitivity using the relative sensitivity obtained through Equation 1 is obtained using Equation 2.

Using the correction value obtained through Equation 2, image quality non-uniformity due to sensitivity difference is compensated for the corresponding image.

In other words, each pixel of the camera output image is corrected by multiplying the correction value obtained by using Equation 2, and then the corrected image is displayed on the display unit 240.

3 is a flowchart illustrating a method of improving image quality of a mobile terminal equipped with a digital camera according to an exemplary embodiment of the present invention.

Referring to FIG. 3, when the camera is activated (S300), the mobile terminal measures the luminance of each pixel of the image photographed by the activation of the camera (S302).

After performing step 302, the mobile terminal extracts the luminance of the central pixel (S304), and then obtains a relative sensitivity for each pixel of the image (S306). That is, the mobile terminal obtains the relative sensitivity by using the luminance of each pixel as the ratio of the luminance of the extracted central pixel.

After performing step 306, the mobile terminal obtains a correction value for correcting the difference in relative sensitivity using the obtained relative sensitivity (S308), and compensates for image quality non-uniformity using the obtained correction value (S310).

Then, the mobile terminal displays the image compensated for the image quality non-uniformity on the display unit (S312).

4 is a flowchart illustrating a method for improving image quality uniformity using a predetermined correction value according to an exemplary embodiment of the present invention.

Referring to FIG. 4, when the camera is activated (S400), the mobile terminal extracts a correction value for each pixel stored in advance with respect to an image captured by the camera (S402).

After performing step 402, the mobile terminal compensates for image quality non-uniformity with respect to the corresponding image by using the extracted correction value (S404).

Then, the mobile terminal displays a screen in which the image quality non-uniformity is compensated (S406).

The present invention is not limited to the above embodiments, and many variations are possible by those skilled in the art within the spirit of the present invention.

As described above, according to the present invention, a better image quality can be obtained by compensating for image quality non-uniformity, and there is little cost increase factor by using a software method, and a method and apparatus for improving image quality of a mobile terminal equipped with an economical digital camera Can be provided.

In addition, according to the present invention, it is possible to provide a method and apparatus for improving image quality of a mobile terminal equipped with a digital camera having an effect that can be quickly applied even when using a new camera module.

Claims (8)

A signal processor for converting the size and format of the captured image into a desired shape and compensating image quality non-uniformity for each pixel of the image; Wireless unit for transmitting the image compensated for the image quality non-uniformity through an antenna; And A display unit for displaying an image compensated for the image quality non-uniformity Device for improving the image quality of a mobile terminal equipped with a digital camera comprising a. The method of claim 1, And a memory for storing the image compensated for the image quality non-uniformity. The method of claim 2, The memory stores a predetermined sensitivity correction value for each type of mobile terminal, and the signal processor compensates for image quality non-uniformity of the corresponding image using the stored correction value. Improve device. The method of claim 1, The signal processor may include a size converter for converting a corresponding image into a desired size; A format converter for converting the video into a desired format; A digital camera comprising a sensitivity adjusting unit for measuring a luminance of each pixel of the image to obtain a relative sensitivity for each pixel, and calculating a correction value using the obtained relative sensitivity to compensate for image quality non-uniformity of the image. Device for improving the quality of the equipped mobile terminal. The method of claim 4, wherein The relative sensitivity is quantified by the relative luminance value of the remaining pixels with respect to the luminance of the screen center pixel, the image quality improving device of a mobile terminal equipped with a digital camera. The method of claim 4, wherein The correction value is 1 / relative sensitivity, characterized in that the image quality improving device of a mobile terminal equipped with a digital camera. Measuring luminance of each pixel with respect to the image photographed by the activation of the camera; Extracting luminance of the center pixel, and then obtaining relative sensitivity with respect to the remaining pixels; Obtaining a correction value for correcting the difference in relative sensitivity using the obtained relative sensitivity; Compensating for image quality non-uniformity using the obtained correction value; and Displaying an image compensated for the image quality non-uniformity Quality improvement method of a mobile terminal equipped with a digital camera comprising a. Extracting a correction value for each pixel stored in advance with respect to the image photographed by the activation of the camera; Compensating for image quality non-uniformity for the corresponding image only by using the extracted correction value; and Displaying an image compensated for the image quality non-uniformity Image quality improvement method of a mobile terminal equipped with a digital camera comprising a.