Chon ong kinh CCTV phu hop
Chon ong kinh dung la yeu to then chot de CCTV hoat dong hieu qua. Tim hieu ve tieu cu, tuong thich cam bien va cach ghep ong kinh voi yeu cau.
Hieu ve tieu cu
Tieu cu (do bang mm) xac dinh goc nhin cua ong kinh. Tieu cu ngan hon (2,8-4mm) la goc rong va hien thi khu vuc lon hon. Tieu cu dai hon (25-50mm) la ong kinh tele, phong to cac vat the xa.
Pham vi tieu cu:
- 2,8-3,6mm: Goc rong, FOV 80-110 do
- 4-8mm: Tieu chuan, FOV 50-80 do
- 12-25mm: Tele, FOV 15-50 do
- 35-50mm: Tele manh, FOV duoi 15 do
Phan loai ong kinh
Ong kinh tieu cu co dinh
Tieu cu co dinh va khong the thay doi. Re hon, don gian hon, nhung kem linh hoat. Pho bien nhat trong CCTV.
Ong kinh varifocal
Tieu cu co the dieu chinh (vd: 2,8-12mm). Dat hon, nhung cho phep tinh chinh chinh xac sau khi lap dat.
Zoom dong co
Tieu cu dieu chinh bang dien. Dat nhat, nhung cho phep dieu chinh tu xa tu trung tam giam sat.
PTZ (Pan-Tilt-Zoom)
Camera co the xoay, nghieng va phong to. Dung de giam sat chu dong, khong phai giam sat co dinh thong thuong.
Ghep noi kich thuoc cam bien
Ong kinh duoc thiet ke cho kich thuoc cam bien cu the. Su dung ong kinh sai cho cam bien sai co the gay ra hien tuong toi goc hoac phu song khong du.
| Kich thuoc cam bien | Ong kinh dien hinh | Ung dung |
|---|---|---|
| 1/3 inch | 2,8-50mm | Giam sat tieu chuan |
| 1/2 inch | 3,6-50mm | Su dung chung |
| 2/3 inch | 4-100mm | He thong chuyen dung |
Huong dan chon ong kinh
Phu song khu vuc rong
Su dung ong kinh goc rong 2,8-3,6mm. Phu song khong gian lon nhung voi chi tiet thap hon. Tot cho phat hien chuyen dong tren khu vuc rong.
Nhan dien khuon mat
Su dung ong kinh 4-6mm lap cach khuon mat 2-3 met. Dam bao chi tiet tot ma khong qua hep khung hinh.
Ghi nhan bien so xe
Su dung ong kinh tele 12-25mm. Dat cach bai dau xe 15-30 met de ghi nhan bien so ro rang.
An ninh chu vi
Su dung ong kinh 6-12mm tren cot hoac goc toa nha. Can bang giua phu song khu vuc va chi tiet.