KR102160911B1 - Image processing apparatus for organic light emitting diode display - Google Patents

Abstract

By analyzing the characteristics of the input image and the compressed image, respectively, and generating the output image, the quality loss is minimized when still images or moving pictures are displayed on the organic light emitting display device, and the compressed image is stored using one frame memory and then delayed. There is provided an image processing apparatus of an organic light emitting display device capable of reducing manufacturing cost while preventing high current from flowing through the organic light emitting display device when the organic light emitting display device is converted from a dark image to a bright image.

Description

Image processing apparatus for organic light emitting diode display

The present invention relates to an image processing device, and more particularly, to an image processing device of an organic light emitting display device capable of reducing manufacturing cost while preventing image quality loss.

As a flat panel display device, a liquid crystal display device has been widely used until now, but the liquid crystal display device requires a backlight as a separate light source, and has technical limitations in brightness, contrast ratio, and viewing angle. Accordingly, since it is possible to emit light itself, a separate light source is not required, and interest in an organic light emitting diode device (OLED) that is relatively excellent in brightness, contrast ratio, and viewing angle is increasing.

An organic light-emitting display device includes a light-emitting device, that is, an organic light-emitting device, in which an emission layer is formed between a cathode for injecting electrons and an anode for injecting holes. An organic light emitting display device is a display device that displays an image by emitting light by combining electrons and holes when electrons generated from a cathode of an organic light emitting device and holes generated from an anode are injected into an emission layer.

The maximum brightness, that is, the maximum brightness, of the organic light emitting display device varies depending on the average brightness of the image, that is, the emission area. In addition, in order to calculate the average brightness of an image in the organic light emitting display device, the data of the entire image is required, and the image data of at least one frame must be delayed. In this way, the image data is delayed by one frame to prevent a high current from flowing through the display panel of the organic light emitting display device when switching from a dark image to a bright image.

To this end, in a conventional organic light emitting display device, a memory is provided in the image processing device, and the memory stores input image data and then outputs it by delaying one frame.

1A and 1B are diagrams illustrating an image processing apparatus of a conventional organic light emitting display device.

Referring to FIG. 1A, the conventional image processing apparatus 10 calculates the maximum luminance from the storage unit 1 for storing the input image data Ii and the input image data Ii to calculate the gamma data P-gamma. And a luminance value calculation unit 5 to output.

The storage unit 1 is provided with a plurality of memories 1_1 to 1_4 according to the type of the input image data Ii, for example, the resolution. For example, when the input image data Ii is a UHD image, the storage unit 1 includes four memories 1_1 to 1_4. The storage unit 1 distributes and stores the input image data Ii in the memories 1_1 to 1_4, and then outputs the stored input image data Ii by delaying one frame.

The luminance value calculation unit 5 calculates the maximum luminance of the organic light emitting display panel, and calculates and outputs programmable gamma data P-gamma from the result.

As described above, the conventional image processing apparatus 10 may delay the input image data Ii by one frame by having a plurality of memories 1_1 to 1_4 for storing the input image data Ii.

However, the image processing apparatus 10 illustrated in FIG. 1A increases the number of memories 1_1 to 1_4 required according to the resolution of the input image data Ii, thereby increasing the manufacturing cost of the organic light emitting display device.

Accordingly, as shown in Fig. 1B, in the conventional image processing apparatus 11 according to another embodiment, the storage unit (1 in Fig. 1A) is omitted, and a compression unit for compressing and outputting the input image data Ii ( 7) is provided.

However, since the image processing device 11 shown in FIG. 1B does not have a memory, it is possible to reduce the manufacturing cost of the organic light emitting display device. However, since the input image data Ii is not delayed and output, it is compressed and output. Image quality deterioration such as flicker or distortion occurs due to image loss in a specific image.

According to the present invention, by adjusting the ratio of the original image and the compressed image in the output image according to the characteristics of the input image, the number of memory for storing the input image is reduced, reducing the manufacturing cost and minimizing image loss to prevent image quality deterioration. It is intended to provide an image processing device for an organic light emitting display device.

An image processing apparatus of an organic light emitting display device according to an embodiment of the present invention for achieving the above object includes an image compression/reconstruction module, a first analysis unit, a second analysis unit, and a determination unit.

The image compression/reconstruction module stores an N-th frame compressed image obtained by compressing the N-th frame input image, restores a previously stored (N-1)th frame compressed image, and outputs a reconstructed image.

The first analysis unit analyzes the image characteristics from the N-th frame input image and outputs the first characteristic information, and the second analysis unit analyzes the image characteristics from the compressed image of the N-th frame stored in the image compression/restore module to obtain the second characteristic information. Print.

The determination unit calculates a weight from at least one of the first feature information and the second feature information output from the first analysis unit and the second analysis unit, and mixes the N-th frame input image and the reconstructed image in the output image according to the calculated weight. Adjust the ratio.

The image processing apparatus of the organic light emitting display device according to the present invention can minimize the loss of image quality when a still image or a moving image is displayed on the organic light emitting display device by analyzing the characteristics of the input image and the compressed image respectively and generating an output image. have.

In addition, by delaying and outputting the compressed image by one frame, it is possible to prevent a high current from flowing through the organic light emitting display device when the organic light emitting display device is switched from a dark image to a bright image.

In addition, by storing the compressed image using one frame memory and then delaying the output, it is possible to reduce the manufacturing cost of the organic light emitting display device compared to the conventional image processing device.

1A and 1B are diagrams illustrating an image processing apparatus of a conventional organic light emitting display device.
2 is a diagram illustrating an image processing apparatus of an organic light emitting display device according to an embodiment of the present invention.
3 is a flowchart illustrating an operation of the image processing apparatus shown in FIG. 2.
4 is a diagram showing the configuration of an input image feature analysis unit shown in FIG. 2.
5 is a diagram showing a configuration of a compressed image feature analysis unit shown in FIG. 2.
6 is a diagram illustrating a configuration of a determination unit shown in FIG. 2.

Hereinafter, an image processing apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a diagram illustrating an image processing apparatus of an organic light emitting display device according to an exemplary embodiment of the present invention, and FIG. 3 is a flowchart illustrating an operation of the image processing apparatus illustrated in FIG. 2.

2 and 3, the image processing apparatus 100 may include an image compression/reconstruction module 110, an image feature analysis module 120, a determination unit 130, and a luminance value calculation unit 140. have.

The image compression/restore module 110 may include an image compression unit 111, a storage unit 113, and an image restoration unit 115.

When image data, that is, the input image I1 is provided from the outside (S100), the image compression unit 111 may compress or sample the input image I1 and output it (S110). The image compression unit 111 may compress or sample the input image I1 using a known image compression method or sampling method.

The storage unit 113 may store a compressed or sampled image output from the image compression unit 111, that is, a compressed image I2 (S113). The storage unit 113 may be one frame memory that stores a compressed image I2 of one frame.

The storage unit 113 may update the compressed image I2 previously stored for every frame of the organic light emitting display device. For example, when the image compression unit 111 compresses the N-th frame input image I1 of the organic light emitting display device and outputs the N-th frame compressed image I2, the storage unit 113 ) It is possible to output the frame compressed image I2 and store the Nth frame compressed image I2. The storage unit 113 may output the (N-1)th frame compressed image I2 to the image restoration unit 115.

The image restoration unit 115 may restore the compressed image output from the storage unit 113, that is, the (N-1)th frame compressed image I2 to output the reconstructed image I3 (S115). The image restoration unit 115 may restore the (N-1)th frame compressed image I2 using a known compressed image restoration method or interpolation. The reconstructed image output from the image restoration unit 115, that is, the reconstructed (N-1)th frame image I3 may be output to the determination unit 130 to be described later.

As described above, the image compression/restore module 110 of the present embodiment compresses and stores the Nth frame input image I1 of the organic light emitting display device, and stores the previously stored (N-1)th frame compressed image I2. By restoring the (N-1)th frame reconstructed image I3 may be output.

That is, the image compression/restore module 110 can output the reconstructed image I3, which is delayed by one frame from the input image I1, using a single storage unit 113, and thus the memory is By reducing the number, manufacturing cost of the organic light emitting display device can be reduced.

The image feature analysis module 120 may analyze features of each of the input image I1 and the compressed image I2, and output a result according thereto (S120). The image feature analysis module 120 may include an input image feature analysis unit 121 and a compressed image feature analysis unit 125.

The input image feature analysis unit 121 may analyze the image characteristics of the input image, that is, the N-th frame input image I1, and output the original image feature information CI1.

In addition, the compressed image feature analysis unit 125 may analyze the image characteristics of the compressed image, that is, the N-th frame compressed image I2 output from the image compression unit 111 to output the compressed image feature information CI2. .

The input image feature analysis unit 121 and the compressed image feature analysis unit 125 may operate only one or all of them to output feature information. In addition, the input image feature analysis unit 121 and the compressed image feature analysis unit 125 may be operated simultaneously or sequentially.

4 is a diagram showing the configuration of an input image feature analysis unit shown in FIG. 2.

2 and 4, the input image feature analysis unit 121 analyzes the image characteristics of the original image input to the image processing apparatus 100, that is, the Nth frame input image I1, and the original image feature information ( CI1) can be printed.

The input image feature analysis unit 121 may include a complexity analysis unit 122 and a blocking noise ratio (BNR) analysis unit 123.

The complexity analysis unit 122 may analyze the complexity of the image in the Nth frame input image I1 and output an analysis result, that is, the complexity information Ic. The complexity analysis unit 122 may output different complexity information Ic according to the type of the input image I1.

For example, when the input image I1 is a still image, the complexity analysis unit 122 may output the complexity information Ic of a large size. In addition, when the input image I1 is a moving picture, the complexity analysis unit 122 may output the complexity information Ic having a size smaller than that of a still image.

The BNR analysis unit 123 may analyze a blocking noise ratio in the Nth frame input image I1 and output an analysis result, that is, BNR information Ib. The BNR analyzer 123 may output BNR information Ib of different sizes according to the type of the input image I1.

For example, when the input image I1 is a still image, the BNR analysis unit 123 may output BNR information Ib of a small size. In addition, when the input image I1 is a moving picture, the BNR analysis unit 123 may output BNR information Ib having a larger size than that of a still image.

Meanwhile, the input image feature analysis unit 121 may output at least one of the complexity information Ic and the BNR information Ib for the N-th frame input image I1 as original image feature information CI1. The original image feature information CI1 may be output to the determination unit 130 to be described later.

5 is a diagram showing a configuration of a compressed image feature analysis unit shown in FIG. 2.

2 and 5, the compressed image feature analysis unit 125 analyzes the image characteristics of the compressed image I2 output from the image compression/restore module 110 of the image processing apparatus 100 to analyze the compressed image characteristics. Information (CI2) can be output.

The compressed image feature analysis unit 125 is an image from a pair of compressed images output from the image compression/reconstruction module 110, for example, the (N-1)th frame compressed image (I2) and the Nth frame compressed image (I2). Feature information can be output by analyzing features.

For example, the compressed image feature analysis unit 125 includes an N-th frame compressed image I2 output from the image compression unit 111 of the image compression/restore module 110 and a storage unit of the image compression/restore module 110 ( The image characteristics of the compressed image I2 of the (N-1)th frame output at 113) may be analyzed, and the compressed image characteristic information CI2 may be output according to the analysis result.

The compressed image feature analysis unit 125 includes a pixel level calculation unit 126, an average picture level (APL) calculation unit 127, a histogram calculation unit 128, and a standard deviation ( Standard Deviation) may include a calculation unit 129.

The pixel level calculation unit 126 compares pixels corresponding to each other in the (N-1)th frame compressed image I2 and the Nth frame compressed image I2, and calculates a pixel level difference according to the comparison result to obtain a pixel level. Information Ip can be output.

The pixel level calculator 126 may output pixel level information Ip having different sizes according to the type of the compressed image. For example, when both the (N-1)th frame compressed image I2 and the Nth frame compressed image I2 are compressed images for a still image, the pixel level calculator 126 provides the pixel level information Ip of a small size. ) Can be printed. However, when both the (N-1)th frame compressed image I2 and the Nth frame compressed image I2 are compressed images for a moving picture, the pixel level calculator 126 is a pixel having a size larger than that of a still image. Level information Ip can be output.

The APL calculation unit 127 calculates an image average value for each of the (N-1)th frame compressed image I2 and the Nth frame compressed image I2, and calculates APL information according to the difference between the calculated image average values of the two frames. (Ia) can be output.

The APL calculator 127 may calculate an image average value in each frame according to Equation 1 below.

[Equation 1]

Here, m is an image average value, I2(k) is a compressed image, and n is the total number of pixels in the organic light emitting display device.

The APL calculator 127 may output APL information Ia of different sizes according to the type of compressed image. For example, when both the (N-1)th frame compressed image I2 and the Nth frame compressed image I2 are compressed images for a still image, the APL calculator 127 calculates APL information Ia of a small size. Can be printed. However, when both the (N-1)th frame compressed image I2 and the Nth frame compressed image I2 are compressed images for moving pictures, the APL calculation unit 127 provides APL information having a larger size than that of a still image. (Ia) can be output.

The histogram calculation unit 128 calculates an image histogram for each of the (N-1)th frame compressed image I2 and the Nth frame compressed image I2, and calculates histogram information according to the difference between the calculated image histograms of the two frames. (Ih) can be output.

The histogram calculator 128 may output histogram information Ih of different sizes according to the type of the compressed image. For example, when both the (N-1)th frame compressed image I2 and the Nth frame compressed image I2 are compressed images for a still image, the histogram calculator 128 calculates the histogram information Ih of a small size. Can be printed. However, when both the (N-1)th frame compressed image (I2) and the Nth frame compressed image (I2) are compressed images for moving pictures, the histogram calculation unit 128 provides histogram information having a larger size than that of a still image. (Ih) can be output.

The standard deviation calculation unit 129 calculates an image standard deviation for each of the (N-1)th frame compressed image I2 and the Nth frame compressed image I2, and calculates the difference between the calculated image standard deviations of the two frames. Accordingly, the deviation information Is can be output.

The standard deviation calculation unit 129 may calculate the image standard deviation in each frame according to Equation 2 below.

[Equation 2]

Here, σ denotes an image standard deviation, I2(k) denotes a compressed image, n denotes the total number of pixels in the organic light emitting display device, and m denotes an image average value.

The standard deviation calculator 129 may output APL information Ia having different sizes according to the type of compressed image. For example, when both the (N-1)th frame compressed image I2 and the Nth frame compressed image I2 are compressed images for a still image, the standard deviation calculation unit 129 provides a small amount of deviation information Is Can be printed. However, when both the (N-1)th frame compressed image I2 and the Nth frame compressed image I2 are compressed images for a moving image, the standard deviation calculation unit 129 has a larger deviation than the still image. Information (Is) can be output.

Meanwhile, the compressed image feature analysis unit 125 outputs at least one of the calculated pixel level information (Ip), APL information (Ia), histogram information (Ih), and deviation information (Is) as compressed image feature information (CI2). can do. The compressed image feature information CI2 may be output to the determination unit 130.

Referring back to FIGS. 2 and 3, the determination unit 130 determines the image ratio according to the feature information output from the image feature analysis module 120, that is, the original image feature information (CI1) and the compressed image feature information (CI2). For example, the ratio of the original image and the compressed image in the output image Io may be determined, and an image according to the ratio may be determined (S130 and S140).

In addition, the determination unit 130 may determine the ratio of the original image and the compressed image in the output image Io according to information output from the luminance value calculator 140 to be described later, for example, the maximum luminance information CI3.

In other words, the determination unit 130 includes the original image feature information CI1 and the compressed image feature information CI2 output from the image feature analysis module 120 and the maximum luminance information CI3 output from the luminance value calculator 140. ) Calculates a weight according to at least one of (S130), determines the ratio of the input image I1 and the reconstructed image I3 according to the calculated weight, and determines the ratio of the input image I1 and the reconstructed image I3 according to this ratio. An output image Io in which) is mixed may be generated and output (S140).

Here, the determination unit 130 may determine a blending ratio by calculating weights for each image, that is, each of the input image I1 and the reconstructed image I3.

6 is a diagram illustrating a configuration of a determination unit shown in FIG. 2.

2 and 6, the determination unit 130 may include a weight calculation unit 131 and an image mixing unit 133.

The weight calculation unit 131 may calculate a first weight value (a) and a second weight value (b) from at least one of original image feature information (CI1), compressed image feature information (CI2), and maximum luminance information (CI3). have.

The weight calculator 131 may calculate the sum of the first weight value (a) and the second weight value (b) to be 1. For example, the weight calculation unit 131 calculates a first weight (a) using original image feature information (CI1), compressed image feature information (CI2), and maximum luminance information (CI3), and then calculates the calculated first weight value. The second weight (b) can be calculated by subtracting (a) from 1.

For example, in the case of calculating the first weight value (a) using all of the original image feature information (CI1), compressed image feature information (CI2), and maximum luminance information (CI3), the first weight value (a) and the second weight value (b) can be calculated by the following [Equation 3].

[Equation 3]

Here, Coeffa is the first weight, Coeffb is the second weight, Ic is the complexity information, Ib is the BNR information, Ip is the pixel level information, Ia is the APL information, Ih is the histogram information, Is is the deviation information, and CI3 is the maximum luminance information. Means. Further, f(n) refers to each frame of the organic light emitting display device, and f(x,y) refers to each pixel of the organic light emitting display device.

Meanwhile, when the input image I1 has a high complexity, that is, when the complexity information Ic is large, the weight calculation unit 131 may calculate a first weight a greater than the second weight b. In addition, when the BNR of the input image I1 is low, that is, when the BNR information Ib is small, the weight calculation unit 131 may calculate a first weight a greater than the second weight b.

Further, the weight calculator 131 may calculate a first weight (a) greater than the second weight (b) when the pixel level difference of the compressed image I2 is small, that is, when the pixel level information Ip is small. have. In addition, the weight calculator 131 may calculate a first weight (a) greater than the second weight (b) when the difference in the average image level of the compressed image I2 is small, that is, when the APL information Ia is small. have. In addition, the weight calculation unit 131 may calculate a first weight (a) greater than the second weight value (b) when the histogram difference of the compressed image I2 is small, that is, when the histogram information Ih is small. In addition, the weight calculation unit 131 may calculate a first weight (a) greater than the second weight (b) when the difference in the image standard deviation of the compressed image (I2) is small, that is, when the deviation information (Is) is small. have.

In addition, when the maximum luminance of the input image I1 is low, that is, when the maximum luminance information CI3 is small, the weight calculation unit 131 may calculate a first weight a greater than the second weight b. .

The image mixing unit 133 is an output obtained by varying the ratio of the input image I1 and the reconstructed image I3 according to the first weight value (a) and the second weight value (b) output from the weight calculation unit 131. An image Io can be generated.

The image mixing unit 133 applies the first weight (a) to the input image (I1) and the second weight (b) to the reconstructed image (I3), so that the original image from the final output image (Io) The ratio of the input image I1 and the compressed image, that is, the reconstructed image I3 may be different.

As described above, when the image complexity is high or the BNR, pixel level difference, APL difference, histogram difference, standard deviation difference, and maximum luminance are small, the weight calculation unit 131 is The weight (a) can be calculated. Accordingly, the image mixing unit 133 may generate the output image Io by mixing the two images so that the input image I1 has a greater ratio than the reconstructed image I3.

In addition, in a case opposite to the above-described case, the weight calculation unit 131 may calculate a second weight (b) greater than the first weight (a). Accordingly, the image mixing unit 133 may generate the output image Io by mixing the two images so that the reconstructed image I3 has a greater ratio than the input image I1.

Referring back to FIG. 2, the luminance value calculator 140 may calculate the maximum luminance from the input image I1 and output maximum luminance information CI3. The maximum luminance information CI3 may be provided to the determination unit 130 described above.

As described above, the image processing apparatus 100 according to the present embodiment analyzes the characteristics of the input image I1 and the compressed image I2 to generate the output image Io, so that the organic light emitting display device When is displayed, the loss of image quality can be minimized.

In addition, by using one storage unit 113, that is, one frame memory, to store the compressed image I2, delay and restore it by one frame, and output it, the organic light-emitting display device can display a bright image from a dark image. In this case, high current can be prevented from flowing, and the number of memories can be reduced compared to the prior art, thereby reducing the manufacturing cost of the organic light emitting display device.

Although many items are specifically described in the above description, this should be interpreted as an example of a preferred embodiment rather than limiting the scope of the invention. Therefore, the invention should not be determined by the described embodiments, but should be determined by the claims and equivalents to the claims.

100: image processing device 110: image compression/restore module
111: image compression unit 113: storage unit
115: image restoration unit 120: image feature analysis module
121: input image feature analysis unit 122: complexity analysis unit
123: BNR analysis unit 125: compressed image feature analysis unit
126: pixel level calculation unit 127: APL calculation unit
128: histogram calculation unit 129: standard deviation calculation unit
130: determination unit 131: weight calculation unit
133: image mixing unit 140: luminance value calculating unit

Claims (12)

An image compression/reconstruction module for storing an N-th frame compressed image obtained by compressing the N-th frame input image, and outputting a restored image by restoring a previously stored (N-1)th frame compressed image;
A first analysis unit that analyzes image features from the Nth frame input image and outputs first feature information;
A second analysis unit that analyzes image features from the N-th frame compressed image and outputs second feature information; And
Organic comprising a determination unit that calculates a weight from at least one of the first feature information and the second feature information, and generates an output image by adjusting a mixing ratio of the Nth frame input image and the reconstructed image according to the weight Image processing device of light-emitting display device. The method of claim 1, wherein the first analysis unit,
A complexity analysis unit that analyzes image complexity from the Nth frame input image and outputs complexity information; And
An image processing apparatus of an organic light emitting display device comprising a BNR analysis unit configured to output BNR information by analyzing a blocking noise ratio in the Nth frame input image. The method of claim 2,
The first analysis unit outputs at least one of the complexity information and the BNR information as the first feature information. The method of claim 2,
When the complexity information output from the first analysis unit is large or the BNR information is small, the determination unit calculates the weight so that the ratio of the input image of the Nth frame in the output image is higher than the ratio of the reconstructed image. Image processing device of organic light emitting display device. The method of claim 1, wherein the second analysis unit,
A pixel level calculator configured to output pixel level information according to a level difference between corresponding pixels in the (N-1)th frame compressed image and the Nth frame compressed image;
An APL calculator configured to output APL information according to a difference between an average image value of the (N-1)th frame compressed image and the Nth frame compressed image;
A histogram calculator configured to output histogram information according to a histogram difference between the (N-1)th frame compressed image and the Nth frame compressed image; And
An image processing apparatus of an organic light-emitting display device comprising a standard deviation calculation unit for outputting deviation information according to a difference in standard deviation of the (N-1)th frame compressed image and the Nth frame compressed image. The method of claim 5,
The second analysis unit outputs at least one of the pixel level information, the APL information, the histogram information, and the deviation information as the second feature information. The method of claim 5,
If the pixel level information, the APL information, the histogram information, and the deviation information output from the second analysis unit are small, the determination unit is determined that the ratio of the input image of the Nth frame in the output image is less than the ratio of the reconstructed image. An image processing apparatus of an organic light emitting display device that calculates the weight to increase. The method of claim 1, wherein the determination unit,
A weight calculator configured to calculate a first weight value and a second weight value of different levels from at least one of the first feature information and the second feature information, respectively; And
An image processing apparatus of an organic light emitting display device comprising an image mixing unit configured to generate the output image by applying the first weight to the N-th frame input image and applying the second weight to the reconstructed image. The method of claim 8,
The weight calculation unit calculates the first weight value and the second weight value such that the sum of the first weight value and the second weight value becomes 1. An image processing apparatus of an organic light emitting display device. The method of claim 1,
Further comprising a luminance value calculator configured to output maximum luminance information by calculating a maximum luminance from the Nth frame input image,
The determination unit calculates the weight from at least one of the first feature information, the second feature information, and the maximum luminance information. The method of claim 10,
If the maximum luminance information output from the luminance value calculation unit is small, the determination unit calculates the weight so that the ratio of the Nth frame input image in the output image is higher than the ratio of the reconstructed image. Image processing device. The method of claim 1,
The image compression/reconstruction module is an image processing apparatus of an organic light-emitting display device including one frame memory for updating and storing a compressed image for each frame of the organic light-emitting display device.

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