Pixel-level Visible Light Communication (PVLC) is a system that embeds data into each individual pixel of a projected image, enabling machines to retrieve the hidden information. Since the data bit strings are converted to blinking pixels for time-division transmission, the contrast of the projected image deteriorates due to the reduction in the expressible luminance range. In this study, we propose a method to extend the luminance range by inverting the bits based on the brightness of the image pixels. The efficacy of this method is confirmed through both simulations and experiments.