Question

Metric cameras must have: 1. Low lens distortions 2. Fixed focal length 3. Adjustable focal length 4. Reseau mark 5. Fiducial mark

• A. \(\text{1, 2, 4 and 5} \)
• B. \(\text{1, 2 and 5} \)
• C. \(\text{1, 2 and 4} \)
• D. \(\text{1, 3, 4 and 5} \)

Hint:

Metric cameras have fixed focal lengths, low distortion, fiducial marks, and reseau grids to ensure accurate photogrammetric measurements.

Answer 1

The Correct Option is A

Step 1: Understanding metric cameras. Metric cameras are specially designed for photogrammetric applications, ensuring high geometric accuracy and minimal distortions. 
Step 2: Essential features of metric cameras. 
- Low lens distortions (1): Required for precise measurements. 
- Fixed focal length (2): Ensures calibration stability. 
- Reseau marks (4): Grid patterns embedded in the image for geometric corrections. 
- Fiducial marks (5): Reference marks for geometric accuracy. 
- Adjustable focal length (3): Not typical, as stability is preferred in metric cameras. 
Step 3: Selecting the correct option. Since metric cameras require low distortions, fixed focal length, reseau marks, and fiducial marks, the correct answer is a. 1, 2, 4 and 5.