TECHNICAL FIELD

This disclosure relates to an image processing apparatus, an image processing method, and a computer-readable recording medium and, more particularly, to an image processing apparatus to obtain a high-definition image, an image processing method, and a computer-readable recording medium.

BACKGROUND ART

An artificial intelligence (AI) system refers to a system which realizes human-level intelligence and a system in which a machine learns, determines, and becomes smarter, unlike conventional rule-based smart systems. AI system shows a more improved recognition rate as iterations are performed, and becomes capable of more accurately understanding user preference. For this reason, conventional rule-based smart systems are gradually being replaced by deep learning-based AI systems.

An AI technology consists of machine learning (deep learning) and element technologies utilizing machine learning.

Machine learning refers to an algorithm technology of classifying/learning the characteristics of input data by itself, and an element technology refers to a technology of simulating functions of a human brain such as cognition and determination by using a machine learning algorithm such as deep learning, and includes fields of technologies such as linguistic understanding, visual understanding, inference/prediction, knowledge representation, operation control, or the like.

Examples of various fields to which AI technologies are applied are as follows. Linguistic understanding refers to a technology of recognizing languages/characters of humans, and applying/processing them, and includes natural speech processing, machine translation, communication systems, queries and answers, voice recognition/synthesis, and the like. Visual understanding refers to a technology of recognizing an object in a similar manner to human vision, and processing the object, and includes recognition of an object, tracking of an object, search of an image, recognition of humans, understanding of a scene, understanding of a space, improvement of an image, and the like. Inference/prediction refers to a technology of determining information and then making logical inference and prediction, and includes knowledge/probability based inference, optimization prediction, preference based planning, recommendation, and the like. Knowledge representation refers to a technology of automatically processing information of human experiences into knowledge data, and includes knowledge construction (data generation/classification), knowledge management (data utilization), and the like. Operation control refers to a technology of controlling autonomous driving of vehicles and movements of robots, and includes movement control (navigation, collision, driving), operation control (behavior control), and the like.

Meanwhile, a lot of studies to improve image quality in terms of a peak signal-to-noise ratio (PSNR), structural similarity (SSIM), or the like, commonly used in quantitative image quality evaluation have been conducted. However, the image quality is influenced by various factors such as human sensitivity or symbol, the technologies developed to date have a limit in improving image quality from a cognitive perspective.

Recently, image quality improvement technologies may be divided into two large categories of a method of not using an external database and a method of using the external database. In the method of not using an external database, super-resolution using very deep convolutional networks (VDSR) was developed. However, in a texture region which may express texture but has a lot of high-frequency components, such as grass, fabric, and the like, performance is still insufficient. In the technologies using an external database, image quality has been improved to some degree even in a texture region, but it is difficult to apply the technologies to a TV or a mobile terminal because a memory of 200 MB or more is used.

Therefore, there is a need for a technology capable of improving the image quality of a texture region of an image without using an external database.

DISCLOSURE

Technical Problem

The disclosure provides an image processing apparatus to obtain a high-definition image by using a low-definition image which is inputted without using external database, an image processing method thereof, and computer-readable recording medium.

Technical Solution

According to an embodiment of the disclosure, an image processing apparatus according to an embodiment of the disclosure includes an input unit to which an image is input, and a processor which extracts visual characteristics by reducing the input image and obtains a high-definition image by reflecting the extracted visual characteristics on the input image.

The processor may reduce the input image using a preset scale factor.

The processor may perform pre-processing to improve image quality of the input image and obtain the high-definition image by reflecting visual characteristics extracted by reducing the pre-processed image into the pre-processed image.

The image processing apparatus may further include a storage for storing a plurality of scale factors corresponding to a plurality of degrees of degradation, and the processor may determine a degree of degradation of the input image based on an image quality improvement rate of the pre-processed image which is measured by comparing with the input image, and reduce the input image using a scale factor corresponding to the determined degree of degradation from among the plurality of stored scale factors.

The processor may arrange the plurality of reduced images to correspond to a size of the input image and extract visual characteristics from the arranged image.

The processor may obtain a high-definition image by reflecting the extracted visual characteristics to only a part of a region in the input image.

The part of a region may have a frequency of an image signal which is greater than or equal to a predetermined value.

The image processing apparatus may further include a display unit to display the obtained high-definition image.

The image processing apparatus may further include a communicator to transmit the obtained high-definition image to a display device.

An image processing method according to an embodiment of the disclosure includes receiving an input of an image, reducing the input image, extracting visual characteristics from the reduced image, and obtaining a high-definition image by reflecting the extracted visual characteristics to the input image.

The reducing may include reducing the input image using a predetermined scale factor.

The method may further include performing pre-process to improve image quality of the input image, and the reducing may include reducing the pre-processed image.

The method may further include storing a plurality of scale factors corresponding to a plurality of degrees of degradation of an image, and the reducing may include determining a degree of degradation of the input image based on an image quality improvement rate of the image of which the image quality is improved, the improvement rate being measured by comparing with the input image, and reducing the input image using a scale factor corresponding to the determined degree of degradation from among the plurality of stored scale factors.

The extracting may include arranging the plurality of reduced images to correspond to a size of the input image and extracting visual characteristic from the arranged image.

The obtaining may include obtaining a high-definition image by reflecting the extracted visual characteristics to only a part of a region in the input image.

In this case, the part of a region may have a frequency of an image signal which is greater than or equal to a predetermined value.

The method may further include displaying the obtained high-definition image.

The method may further include transmitting the obtained high-definition image to a display device.

A computer-readable recording medium including a program to execute an image processing method according to an embodiment of the disclosure includes receiving an input of an image, reducing the input image, extracting visual characteristics from the reduced image, and obtaining a high-definition image by reflecting the extracted visual characteristics to the input image.

