Luminous emittance vs value recorded on image sensor

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The discussion focuses on estimating the gray level or RGB values of a light bulb and a gray wall based on their luminous emittance. The light bulb has an emittance of 160,000 lux (16 ev), while the wall has 300 lux (7 ev), resulting in a ratio of 533:1. Given an 8-bit grayscale where the bulb's gray level is 255, the wall's gray level would be significantly lower due to the exposure settings favoring the bulb. The 8-bit A to D conversion limits the ratio it can accurately represent to 255, indicating that the wall would likely appear very dark in the image. This highlights the challenges of capturing high dynamic range scenes with standard imaging techniques.
jamesdo
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Assume that I have a light bulb with luminous emittance of 160000lux (16ev), and a gray wall with luminous emittance of 300lux (7ev). I take the photo of this bulb and this background. Is there any approximate formula to estimate the gray level or RGB value of the bulb and the background in the image. In this case, I assume that the exposure is set for the light bulb (so the background should be very dark). Let's say the grayscale is 8 bits. If the gray level of the bulb is 255, what would be the gray level of the wall.

Thanks!
 
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jamesdo said:
Assume that I have a light bulb with luminous emittance of 160000lux (16ev), and a gray wall with luminous emittance of 300lux (7ev). I take the photo of this bulb and this background. Is there any approximate formula to estimate the gray level or RGB value of the bulb and the background in the image. In this case, I assume that the exposure is set for the light bulb (so the background should be very dark). Let's say the grayscale is 8 bits. If the gray level of the bulb is 255, what would be the gray level of the wall.

Thanks!
The lamp and the wall have a ratio of emittance of 533. If you use an eight bit A to D conversion it can only handle a ratio up to 255.
 
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