**4. Experiment**

In this section, we describe the settings and the results of our experiments. In backlight extraction, the base backlight extraction methods in our experiment consisted of the max method [4], the average method [4], LUT method [6], CDF method [7], IMF method [8], the method based on Otsu [10], PSNR method [11], and Gaussian method [12]. The method based on Otsu in [10] was considered as the target algorithm, extracted by which the backlight is taken as the target backlight. The sizes of the input image and the backlight are 1920 × 1080 and 66 × 36, respectively.

#### *4.1. Hardware*

A self-designed LED-LCD prototype display [10] was adopted to verify display quality with the optimal backlight and compensated image that is the output in Figure 3. The display principle of the prototype is shown in Figure 7a. The measure environment in our experiment was a dark room to prevent interference from light. The luminance meter used in our experiment is CX-2B color brightness meter, for which the luminance ranges in 0.001–200 kcd/m2.

**Figure 7.** Hardware support: (**a**) display principle of LED-LCD prototype; and (**b**) measurement environment (the lights were off when we measured the luminance).
