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Distance Formula:
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Distance calculation from a picture uses the principle of similar triangles in photography to estimate the distance between the camera and an object when you know the object's actual height and its height in the image.
The calculator uses the formula:
Where:
Explanation: This formula is derived from the principle of similar triangles in optics, where the ratio of the object's actual size to its image size equals the ratio of the object distance to the focal length.
Details: This calculation is useful in photography, surveillance, robotics, computer vision applications, and forensic analysis where distance measurement from images is required.
Tips: Enter the focal length of your camera lens in millimeters, the actual height of the object in millimeters, and the height of the object as it appears in your image in pixels. All values must be positive numbers.
Q1: How accurate is this distance calculation method?
A: Accuracy depends on precise measurement of inputs. It works best with telephoto lenses and when the object is perpendicular to the camera axis.
Q2: Can I use different units of measurement?
A: Yes, but all measurements must use the same units for consistent results. The calculator currently uses millimeters for physical measurements.
Q3: Does this work for width measurements as well?
A: Yes, the same formula applies if you use width instead of height, provided the object's orientation is consistent.
Q4: What if my camera has digital zoom?
A: Digital zoom may affect accuracy as it doesn't change the actual focal length but rather crops and enlarges the image digitally.
Q5: Can this be used with smartphone cameras?
A: Yes, but you need to know the actual focal length of your smartphone camera, which may be fixed or vary between models.