||The Study of Image Processing IPs for LCD TV
||Department of Electrical Engineering
High dynamic range
|| 在平面電視全球普及率節節攀升趨勢下，LCD TV已成為消費者第一指名購買的3C產品。而一般消費者在考慮購買前，除了品牌的形象考量外，針對硬體本身性能中，畫面呈現的整體品質是驅動消費者最主要的購買因素。故目前各大LCD TV控制晶片廠商中，皆有其各自處理畫質的核心技術。
|| As the increasing share of TV market, LCD TV becomes the most popular 3C product in the minds of consumers. Besides the brand name of LCD TV, the picture quality is a very important factor to determine the purchasing decision of customer. Consequently, every corporation of LCD TV chip provider has its own picture quality processing engine. In general, the picture quality processor includes a front-end filter, deinterlacing, and post color and contrast adjustment. The work in this thesis is to propose a novel chromatic adjusting scheme of LCD TV without over-saturation, which can be implemented in hardware IP or an embedded function in TV controller SOC.
The color setting of every branded LCD TV is not the same due to the characteristic of LCD panel and the market location. Furthermore, every user may have his own favorite color setting. Therefore, a chromatic adjustment is necessary in the LCD TV controller. The traditional methods of chromatic adjustment suffer from the hardware cost and computing power, and hence it can’t not specify the exact boundary of color space. It usually causes over-saturation after chromatic adjustment and loses the color tone detail. In this thesis, a novel chromatic adjusting scheme without any over-saturation is proposed. By exactly calculating the boundary of color space, this scheme can generate the vivid colors and preserve more detail in high saturation area of an image frame. Unlike the traditional methods, the proposed scheme can be easily implemented in hardware IP which is suitable for integration in SOC.
In this work, a novel chromatic adjusting processing scheme for LCD TV is proposed. The chromatic adjusting scheme can make the picture quality more colorful after the favorite color adjustment by the user. The image frame will have no over-saturation and preserves the image detail after this color adjusting scheme. Comparing with traditional method, this scheme can be implemented in hardware, whish means it can be easily adopted in SOC chip.
||TABLE OF CONTENTS
Chapter 1 Introduction 1
1.1 Overview 1
1.2 Challenges 3
1.3 Overview of Thesis 5
Chapter 2 Color Appearance Models 6
2.1 What is Color 6
2.2 Color Vision 7
2.1.1 The Receptors in Human Eyes 7
2.1.2 Visual Signal Transmission 8
2.1.3 Basic Relative Attributes of Color 9
2.2 Tristimulus Values 10
2.2.1 The Basic Concept of the Tristimulus values 10
2.2.2 The Tristimulus Values 12
2.2.3 Theoretical Consequences 12
2.2.4 Chromaticity Coordinates 13
2.2.5 Spectrum Locus 14
2.3 Color Appearance Models 15
2.3.1 Common Color Spaces 17
2.3.2 Computer RGB color space 17
2.3.2 CMY Color Space 18
2.3.3 CIE XYZ and xyY Color Spaces 19
2.4 Conclusion 21
Chapter 3 Picture Quality Adjustment for LCD TV 23
3.1 Color Space Introduction 23
3.2 Color Data Path in LCD TV 27
3.3 Color Adjusting Schemes by Former Researches 28
3.3.1 Scheme Proposed by LG 29
3.3.2 Scheme Proposed by Samsung 30
3.3.3 Scheme Proposed by Ku and Wang 31
3.3 Conclusion 32
Chapter 4 Color Adjustment System without Over-saturation 33
4.1 Introduction 33
4.2 New Method to Solve Oversaturation 36
4.3 Simulation results 47
4.4 Conclusion 52
Chapter 5 System Integration and Implementation of Color Adjusting Scheme 53
5.1 Introduction 53
5.2 Implementation of Boundary Look-Up-Table 53
5.3 Saturation Mapping Scheme 61
5.3 System Integration and Implementation 65
5.4 Further Improvement of Proposed System 68
Chapter 6 Conclusion and Future work 71
LISTS OF FIGURES
Figure 2.1 Relationship between light sources, objects and the human visual system. P7
Figure 2.2 The spectrum responsibility curve of three types of cones. P8
Figure 2.3 Possible types of connections between retinal receptors and nerve fibers. P9
Figure 2.4 Human cones and rods absorption spectra. P11
Figure 2.5 CIE 1931 chromacity. P14
Figure 2.6 RGB color space. P17
Figure 2.7 CMY color space. P18
Figure 2.8 XYZ color space. P19
Figure 2.9 xyY color space. P21
Figure 3.1 A comparison of the some color spaces. P24
Figure 3.2 Block diagram of LCD TV controller P43
Figure 3.3 Saturation adjusting scheme proposed by LG electronics P29
Figure 3.4 The saturation adjusting scheme proposed by Samsung electronics P30
Figure 3.5 The saturation adjusting scheme proposed by Ku and Wang P31
Figure 4.1 Color cube in RGB color space. P33
Figure 4.2 Color cube in YUV color space. P35
Figure 4.3 The hue-saturation relationship in a YUV color space P36
Figure 4.4 The problems when adjusting the saturation of the pixels. P38
Figure 4.5 The mechanism of calculating a boundary of the cube P39
Figure 4.6 The mechanism for obtaining the boundary P40
Figure 4.7 The mechanism for obtaining the boundary (another condition). P43
Figure 4.8 The systematic block diagram of our scheme for adjusting color saturation. P47
Figure 4.9(a) Original image. P48
Figure 4.9(b) Over-saturation image. P49
Figure 4.9(c) Image with new method. P49
Figure 4.10(a) Original image. P50
Figure 4.10(b) Over-saturation image. P51
Figure 4.10(c) Image with new method. P51
Figure 5.1 The flow of calculating color space boundary P54
Figure 5.2 The saturation value of boundary. P58
Figure 5.3 The relationship between a given y and y1 P59
Figure 5.4 The modified flow of boundary calculation P61
Figure 5.5 Traditional scheme of adjusting saturation P62
Figure 5.6 The modified saturation mapping scheme P63
Figure 5.7 Modified saturation mapping scheme P64
Figure 5.8 Further modified saturation mapping scheme P64
Figure 5.9 The block diagram of chromatic adjusting system P66
Figure 5.10 Simulation FPGA board of our method P67
Figure 5.11 Data path of simulation board P68
Figure 5.12 Saturation adjustment with same y. P69
Figure 5.13 Saturation adjustment to the maximum value. P70
LISTS OF TABLES
Table 4.1 Reference points equidistantly distributed between 0 to 2πP45
Table 4.2 Simplified reference points equidistantly distributed between 0 to 2πP45
Table 5.1 The boundary look-up table P55
Table 5.2 The modified boundary look-up table P56
Table 5.3 The further modified boundary look-up table P57
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