Artificial Intelligence/๐Ÿ“–

[๊ฐœ๋…] object detection ๊ด€๋ จ ์šฉ์–ด ์ •๋ฆฌ (1)

geum 2021. 11. 16. 14:02
Classification / Localization / Object Detection

Classification

- ์ž…๋ ฅ์œผ๋กœ ๋“ค์–ด์˜จ ํ•˜๋‚˜์˜ ์ด๋ฏธ์ง€์— ๋Œ€ํ•ด ํ•ด๋‹นํ•˜๋Š” label ์ถœ๋ ฅ

- single object๋ฅผ ๋‹ค๋ฃธ

Localization

- ์ž…๋ ฅ์œผ๋กœ ๋“ค์–ด์˜จ ํ•˜๋‚˜์˜ ์ด๋ฏธ์ง€์—์„œ ํ•œ object์˜ ์œ„์น˜(์ขŒํ‘œ) ์ถœ๋ ฅ

- single object๋ฅผ ๋‹ค๋ฃธ

- object๊ฐ€ ์žˆ๋Š” ๊ณณ์— bounding box๋ฅผ ๊ทธ๋ฆฌ๋Š” ๋ฐฉ์‹

Object Detection

- ์ž…๋ ฅ์œผ๋กœ ๋“ค์–ด์˜จ ํ•˜๋‚˜์˜ ์ด๋ฏธ์ง€์—์„œ ์—ฌ๋Ÿฌ object๋ฅผ ๋ถ„๋ฅ˜ํ•˜๊ณ  ๊ฐ object๋“ค์˜ ์œ„์น˜ ์˜ˆ์ธก

- multi object๋ฅผ ๋‹ค๋ฃธ

- object detection์˜ ๋ฌธ์ œ ํ•ด๊ฒฐ ๋ฐฉ๋ฒ•์œผ๋กœ sliding window๊ฐ€ ๋งŽ์ด ์‚ฌ์šฉ๋˜์—ˆ์Œ

 

IoU

IoU(Intersection over Union)

- bounding box ์˜ˆ์ธก์„ ์–ผ๋งˆ๋‚˜ ์ž˜ํ–ˆ๋Š”์ง€ ํ‰๊ฐ€ํ•  ์ˆ˜ ์žˆ๋Š” ์ง€ํ‘œ

- ๊ฒน์ณ์ง€๋Š” ๋ถ€๋ถ„(Intersection)์„ ์ „์ฒด ๋ถ€๋ถ„(Union)์œผ๋กœ ๋‚˜๋ˆ”

- ๋ชจ๋ธ์ด ์˜ˆ์ธกํ•œ bounding box์™€ ground truth ์‚ฌ์ด์˜ IoU๊ฐ€ ๋†’์„์ˆ˜๋ก ์˜ˆ์ธก์„ ์ž˜ํ•œ ๊ฒƒ

 

 

Precision / Recall

- True/False : ์˜ˆ์ธก = ์‹ค์ œ์ผ ๋•Œ True, ์•„๋‹ˆ๋ฉด False

- Positive/Negative : object๊ฐ€ ์กด์žฌํ•œ๋‹ค๊ณ  ์˜ˆ์ธกํ•  ๊ฒฝ์šฐ Positive, ์กด์žฌํ•˜์ง€ ์•Š๋Š”๋‹ค๊ณ  ์˜ˆ์ธกํ•  ๊ฒฝ์šฐ Negative

 

Precision(์ •๋ฐ€๋„)

- True Positive/(True Positive+False Positive)

- ๋ชจ๋ธ์ด ๊ฒ€์ถœํ•ด๋‚ธ ๊ฒฐ๊ณผ ์ค‘ ์ œ๋Œ€๋กœ ๊ฒ€์ถœํ•œ ๋น„์œจ → "์–ผ๋งˆ๋‚˜ ์ •ํ™•ํ•˜๊ฒŒ ๊ฒ€์ถœํ•˜๋Š๋ƒ?"

 

Recall(์žฌํ˜„์œจ)

- True Positive/(True Positive+False Negative)

- ์ „์ฒด ๊ฒ€์ถœ ๋Œ€์ƒ ์ค‘ ์ œ๋Œ€๋กœ ๊ฒ€์ถœํ•œ ๋น„์œจ → "๊ฒ€์ถœํ•ด๋‚ด์•ผ ํ•˜๋Š” ๋Œ€์ƒ ์ˆ˜๋ฅผ ์–ผ๋งˆ๋‚˜ ์ž˜ ์žฌํ˜„ํ•˜๋Š๋ƒ?"