1. What is Frame Rate?
Essentially, a video is composed of a sequence of still images. These still images are the smallest unit of a video, known as frames. Frame rate refers to the number of consecutive frames captured or displayed per second, measured in Hz (Hertz) or frames per second (fps). For example, 30 fps means 30 consecutive frames are captured within one second, while 30 Hz means 30 consecutive still frames are displayed per second; both can be simply referred to as 30 frames. Common frame rates include 30 fps, 60 fps, and 120 fps. The higher the frame rate, the smoother the video, which naturally requires more data to be transmitted and increases the cost.

2. How to Measure the Frame Rate of a Camera?
Theoretically, frame rate = number of frames / time, so one could record a video of a fixed duration and directly calculate the frame rate. However, in practice, this method is prone to errors. Due to hardware or driver issues, frame drops may occur, or frame interpolation may be needed during debugging. In such cases, the actual number of frames differs from the counted number, leading to inaccurate frame rate calculations.

Frame dropping occurs when slow data processing causes congestion in the data transmission channel, forcing the system to discard the current or incoming new frames when new data arrives. Frame interpolation, on the other hand, involves inserting additional still frames into the original sequence. Both issues cause the true frame rate to deviate from the counted frame rate, so this method is generally not used in actual measurements. When the camera's frame rate matches the flicker rate of a display, the position of a target in the camera's view should align with its position on the display. Although this may be influenced by subjective factors, theoretically, the higher the flicker precision of the display, the more accurate the subjective judgment.

Frame Rate Measurement Procedure
Test Equipment

To measure the frame rate, we need the test equipment IS-Timer101 Time Tester.

The IS-Timer101 Time Tester is primarily used for testing camera time-related performance, including frame rate testing, exposure time testing, shutter lag testing, rolling shutter testing, flicker testing, and audio-video synchronization testing. The time tester features a 10×10 LED matrix, buttons, knobs, and a display screen. It contains visible and near-infrared spectrum LED light sources, allowing users to select different modes via the touch screen and buttons for corresponding tests.

Frame Rate Measurement Steps

1. First, perform illuminance calibration on the LED surface of the time tester to ensure uniform light reception and reduce subjective errors.

2. Power on the time tester and adjust it to Mode 1: Frame Rate Mode. At this point, the first row of LEDs on the tester starts flickering, and the current frame rate is displayed in the upper corner.

3. Point the camera under test at the LEDs, and adjust the knob on the side of the device to control the LED flicker frequency until the LEDs appear stationary on the camera's display. The frequency displayed on the tester at this point equals the frame rate of the camera.

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