Please help, how much computation does it take for software to perform lens distortion correction?

littleshrimp

Please help, how much computation does it take for software to perform lens distortion correction? [Copy link]

 

Since I can't find a suitable MPU with hardware LDC (lens distortion correction), I want to know how much computation is required to implement LDC using software, and what configuration of MPU is required at least?

IC爬虫

If the distortion is symmetrical along the center of the image and the amount of calculation is not large, a 640*480 single-channel image at 400MHZ can be done in real time.

littleshrimp

IC Crawler published on 2022-9-26 20:19 If the distortion is symmetrical along the center of the image, the amount of calculation is not large, and a 640*480 single-channel image at 400MHZ can be done in real time

I forgot to mention the resolution and frame rate. Is 1280*720 30fps achievable using software on a common MPU?

IC爬虫

littleshrimp posted on 2022-9-26 20:22 I forgot to mention the resolution and frame rate. Is 1280*720 30fps achievable by software for a standard MPU?

Single channel?

If a simpler interpolation algorithm is used, this should also be possible using a 600Mhz chip.

littleshrimp

IC Crawler published on 2022-9-26 21:05 Is it single channel? If a simpler interpolation algorithm is used, and a 600Mhz chip is used, it should be possible.

It is single channel, but the lens has not been finalized yet, so there may be severe tangential distortion.

IC爬虫

littleshrimp posted on 2022-9-27 07:59 It is a single channel, but the lens has not been confirmed yet, and there may be more serious tangential distortion

Tangential distortion may be caused during assembly

chunyang

Even the STM32 cannot perform real-time lens distortion correction in video shooting, but it can be done for static photos.

chunyang

If you have your own lens, it is difficult to obtain the calibration parameters, and you need professional equipment to test it. Digital SLRs, PhotoShop, etc. all have lens libraries that can be used to obtain calibration parameters based on lens models, and it is probably not realistic to program this yourself.

littleshrimp

chunyang posted on 2022-9-27 11:11 Lens distortion correction in video shooting cannot be done in real time even with STM32, but it can be done for static photos.

STM32 probably won't work, you need to use an MPU with DSP

littleshrimp

IC Crawler published on 2022-9-27 10:08 Tangential distortion may be caused during assembly

The lens is quite special, it is not the round lens that is usually used

chunyang

littleshrimp posted on 2022-9-27 12:27 STM32 is probably not going to work, you need to use an MPU with DSP

The DSP in digital SLRs handles this, but without data there is nothing you can do...

littleshrimp

chunyang posted on 2022-9-27 13:08 The DSP in digital SLRs handles this, but there is no way to do it without data...

You should first shoot the calibration image through a distorted lens, such as a checkerboard, calculate the distortion data and then apply it to each frame.

chunyang

littleshrimp posted on 2022-9-27 16:01 It should be to first shoot the calibration image through a distorted lens, such as a checkerboard, calculate the distortion data and apply it to the frameless image later.

That also requires manual intervention and testing, which is a lot of work. You might as well consider finding a suitable lens with a low distortion rate.

chunyang

Lens distortion correction requires rotating the lens and testing it at multiple angles. The focus distance also has an impact, so it is very troublesome to do it yourself.

littleshrimp

chunyang posted on 2022-9-27 16:13 That also requires manual intervention and testing, which is a lot of work. You might as well consider finding a suitable lens with low distortion.

There is no way to choose the lens, and distortion is unavoidable.

littleshrimp

chunyang posted on 2022-9-27 16:15 Lens distortion correction requires rotating the lens and testing at multiple angles. The focus distance also has an impact. It is very troublesome to do it yourself.

It requires manual testing, which is troublesome, but I am afraid that I won’t be able to choose the right processor.

chunyang

littleshrimp posted on 2022-9-27 16:21 It needs manual testing, which is troublesome, but I am afraid that I can't choose the right processor.

Then using TI's DSP, the question is - is it worth it?

littleshrimp

chunyang posted on 2022-9-27 16:28 Then using TI's DSP, the question is - is it worth it?

Now I want to determine how much computing power is required and then choose a suitable MPU.

lkh747566933

This sounds very advanced, what does it do? Is the image captured by the lens deformed?

littleshrimp

lkh747566933 posted on 2022-10-29 18:49 This sounds very high-end, what is it for? Is the image captured by the lens deformed?

right