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Formula calculation method:

The Department of computing field field and focal length refers to the uptake of object size, the size of the FOV is the distance to the lens to be ingested objects, and imaging lens head size requirements are determined.

The focal length of the lens, the size of the field of view, and the distance from the lens to the object to be taken are calculated as follows:

F=wL/W

F=hL/H

F: lens focal length

W: the width of the image (the width of the object being imaged on the CCD target surface)

W: the width of the object being photographed

L: the distance from the object to the lens

H: the height of the image (the imaged height on the CCD target), the field of view (the scene of the scene), and the height of the image

H: the height of the subject

CCD target size: mm

Specifications

W

H

1/4"

Three point two

Two point four

1/3"

Four point eight

Three point six

1/2"

Six point four

Four point eight

2/3"

Eight point eight

Six point six

1"

Twelve point seven

Nine point six

Since the width and height of the camera screen are the same as the screen width and height of the television receiver, the ratio is 4:3. When the L is unchanged and the H or W increases, the f becomes smaller, and when H or W remains unchanged and the L increases, the f increases.

Calculation of FOV angle:

If the horizontal or vertical field of view is known, the width and height of the field can be calculated according to the formula.

Horizontal field angle beta (horizontal viewing angle)

=2tg-1= vertical field of view Q (vertical viewing angle)

Q=2tg-1

Type W, H, f ditto

The relation between the horizontal field angle and the vertical field angle is as follows:

Q= or =q camera angles are listed in the table B horizontal view of different sizes and different layers of camera focal length f the angle, if the horizontal or vertical field angle can be calculated by a field angle can be calculated out of the field and the field width W height H

H=2Ltg, W=2Ltg

For example, the camera's camera tube is 17mm (2/3in) and the lens focal length f is 12mm. From the point of view of the horizontal field of view is 40 degrees, and the distance between the lens and the ingested object is 2m, the width of the field of view is w.

W=2Ltg=2 * 2tg=1.46m is H=W= * 1.46=1.059m

The longer the focal length is, the smaller the f field angle is, the smaller the target will be.

As shown before, the camera's field of view by the width (W), high (H) and camera distance (L), once the decision to the camera to monitor the scene, the correct choice of the focal length of the lens on the origin of 3 factors; the distance of camera imaging device to monitor the * *. The dimension of the object camera. And the scenery of the ruler: "1/3, 1/2" 2/3, "or 1".

Diagram select the lens step: the required field of view has a simple relationship with the focal length of the lens. Use this relationship to select the appropriate lens. The maximum width of an estimated or measured field of view; an estimate or measurement of the distance between the camera and the object being photographed. Specific method: in W and L for coordinate axis icon 2-5, find out the lens focal length should be selected. To ensure that the scene is completely contained in the field of view, the number indicated on the line at the intersection of the coordinates should be selected.

For example, the field of view is 50m wide, and the distance is 40m. Use the 1/3 "format" lens, and the intersection point in the coordinate map is a little higher than the line representing the 4mm lens. This shows that if you use the 4mm lens, you cannot override the field of view of the 50m. With the 2.8mm lens, you can completely cover the field of view.

F=vD/V

F=hD/H

Among them, f represents the focal length, V represents the vertical height of the CCD target surface, V stands for the height of the observed object, H represents the horizontal width of the CCD target surface, and H represents the width of the observed object.

For example: suppose 1/2 CCD camera observation, the object was 440 mm wide, 330 mm high, the lens focus from the object 2500 mm. It can be worked out by the formula:

The focal length is f=6.4X2500/440 or 36 mm

The focal length f=4.8X2500/330 = 36 mm

When the focal value is calculated, if there is no lens corresponding to the focal length is normal, then you can choose a similar model according to the product catalog, the general choice is smaller than the calculated value, so that the angle of view will be larger.

Angle of common camera lens:

Simply put, the larger the camera's lens, the farther and narrower it sees; the smaller the camera lens, the closer and wider it becomes.

Lens focal length (mm)

1/3, around the chip

Shooting angle

1/3 "chips up and down."

Shooting angle

1/4, around the chip

Shooting angle

1/4 "chips up and down."

Shooting angle

2.5mm

96.4 degrees

86.2 degrees

81.9 degrees

72.9 degrees

2.8mm

89.9 degrees

79.8 degrees

75.6 degrees

66.8 degrees

3.6mm

75.7 degrees

66 degrees

62.2 degrees

54.3 degrees

4mm

69.9 degrees

60.7 degrees

57 degrees

49.5 degrees

6mm

50 degrees

42.6 degrees

39.8 degrees

34.2 degrees

8mm

38.5 degrees

32.6 degrees

30.4 degrees

26 degrees

12mm

26.2 degrees

22.1 degrees

20.5 degrees

17.5 degrees

16mm

19.8 degrees

16.6 degrees

15.4 degrees

13.2 degrees

30mm

10.6 degrees

8.9 degrees

8.3 degrees

7 degrees

60mm

5.3 degrees

4.5 degrees

4.1 degrees

3.5 degrees

100mm

3.2 degrees

2.7 degrees

2.5 degrees

2.1 degrees

200mm

1.6 degrees

1.3 degrees

1.2 degrees

1.1 degrees

Wide range of camera lens used:

focal length

Specifications

angle

2.1 mm small lens

1/3

150 degrees

2.5 mm small lens

1/3

130 degrees

2.8 mm small lens

1/3

115 degrees

2.8 mm fixed iris

1/3

115 degrees

2.8 mm

1/3

96 degrees

4 mm

1/3

78 degrees

6 mm

1/3

53 degrees

8 mm

1/3

40 degrees

12 mm

1/3

23 degrees

16 mm

1/3

17 degrees

3.5-8 mm

1/3

96 degrees - 45 degrees

6-15 mm

1/3

54 degrees - 23 degrees

6-36mm electric zoom lens

1/3

51 degrees - 9 degrees

8.5-51mm electric zoom lens

1/3

57 degrees - 10 degrees

6-60mm electric zoom lens

1/3

52 degrees - 6 degrees