How to Solve Global Camera Fly Shooting Smear Problem

## How to Solve Global Camera Fly Shooting Smear Problem

* Scope: Global Camera Fly Shooting

### **Problem**

Why does smear phenomenon occur during dynamic shooting?

### **Description**

The image is normal when the object is shot statically, but there is smear phenomenon when shot dynamically.

Static object image: Motion fly shooting image:

![](/media/202601//1769734671.878091.png)

As long as the object moves, there will definitely be smear in shooting. So how to judge whether the fly shooting project can be used? Does smear affect fly shooting? This depends on the detection accuracy requirements of the system. For example, for size measurement projects, smear will have a serious impact on measurement accuracy. In this case, the smear length is required to be as short as possible, requiring no more than 1/3 pixel, or no more than one pixel, etc.; while for identification, counting and other related projects, the requirements for smear will be relatively loose. These requirements are generally like this, not absolute, and collectively depend on the actual situation needs. The relationship between smear and accuracy requirements is calculated in detail below.

### **Answer**

The condition that smear does not affect fly shooting is: Exposure Time * Object Motion Speed ≤ Motion Direction Accuracy Requirement

For example: The current exposure time of the camera is 2000us, the speed of the conveyor belt is 100mm/s, and the camera resolution used is 2448*2048,

The field of view is 300mm*250mm, the direction of object movement is horizontal, and the accuracy requirement is that the smear does not exceed 1/2 pixel. Can the scene at this time meet the fly shooting requirements?

>i
>
>```math
>Exposure Time * Object Motion Speed = 2000 * 100 / 1000000 = 0.2mm
>Horizontal Pixel Accuracy Requirement = 300 / 2448 * 1 / 2 = 0.061mm
>```

Since 0.2mm > 0.061mm, it cannot meet the accuracy requirements of this fly shooting motion scene.

According to the above formula, we have two solutions:

**l Reduce the exposure time of the camera**

Continue to calculate according to the above example, $$0.061mm / 100mm/s = 0.00061s = 610us$$

So when the exposure is reduced to below 610us, the smear will not exceed 1/2 pixel, and the accuracy can meet the requirements. But note that after reducing the exposure, you need to strengthen the brightness of the light source or increase the aperture to make the image reach the same brightness.

**l Reduce the motion speed of the conveyor belt**

Similarly, continue to calculate according to the above example, $$0.061mm / 2000us = 0.0000305mm/us = 30.5mm/s$$

So when the conveyor belt speed is reduced to 30.5mm/s, the smear will not exceed 1/2 pixel, and the accuracy can meet the requirements.

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Click here to jump to the corresponding Chinese manual page: [How to Solve Global Camera Fly Shooting Smear Problem](/doc/319)