Calculating Image Visibility with 500 Lumens

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Homework Help Overview

The discussion revolves around a projector setup with a light source outputting 500 lumens. The original poster is seeking to understand how much light reaches the fresnel lens and how this relates to image visibility, specifically in terms of illuminance and brightness. They also mention the importance of contrast ratio in determining visibility.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to connect the light output to the illuminance at the fresnel lens and questions how to calculate the necessary brightness for clear image visibility. They raise concerns about the relationship between contrast ratio and perceived brightness, and they seek clarification on these concepts.

Discussion Status

The discussion appears to be in its early stages, with the original poster expressing frustration over a lack of responses. There are no explicit solutions or consensus yet, but the original poster is actively seeking suggestions and guidance.

Contextual Notes

The original poster mentions a contrast ratio of about 20:1 but indicates uncertainty about its implications for brightness perception. There may be missing information regarding the specific setup and parameters needed for calculations.

sharp81
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i have this projector setup with a light source having about 500 lumens as its light output.I know the distance to the fresnel lens which will be at the focal distance so that parallel light goes through the lens.
I want to know how much of this light would be falling on the fresnel lens.
I think this should be the illuminance or the brightness.
Now i need to find out how much of the light is required for the eye to see the image clearly.
Since in this case when some lumens is coming out of the light source this shld be converted to candela/steradian and hence i need to determine the angle formed by the light source to the fresnel.This is needed so that i can design the reflector which will be my next in the task.
considering that the contrast ratio is abt 20:1 . i don't have much idea about this contrast ratio and would like to know how this could be related to how much brightness the eye can see.
The brightness and the illuminance at the fresnel need to be found out which can be used with the magnification of the image known to say what the luminance on my final image would be.
 
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will someone be able to help me out.i guess i am the only one whose questions goes unnoticed all the time.
 
still no ones responded to my cry .
 
pleasezz some one help me with some sort of suggestions.please, i am desperate for help
 

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