GA/T 1325-2017Security protection--Face recognition applications--Specifications for acquisition of video and image (English PDF)

4.2.2 Lens

The lens used for dynamic capture selection should meet the following requirements.

a) The maximum aperture of the auto iris lens is not less than F=1.4;

b) The optional lens makes the field of view space XYZ of the collected object's face area as follows, to meet the requirements of 4.1.1 and GA/T 922.2-2011

4.2.1 Requirements.

---600mm<=X<=2800mm;

---450mm<=Y<=2100mm;

---Z>=800mm.

c) Refer to formula (A.3) for the selection of lens focal length f. See Appendix C for design examples.

4.2.3 Interface

The physical and command interface should meet the following requirements.

a) Physical interface. meet the requirements of 5.1.2 in GA/T 1127-2013;

b) Command interface. meet the interface requirements of face acquisition equipment in 5.1.4 of GA/T 1326-2017.

4.3 Acquiring images

4.3.1 File format

The output file format should meet the following requirements.

a) Video compression coding. H.264, H.265, MPEG4, MJPEG or SVAC;

b) Image file format. BMP, RAW, JPEG or JPEG2000, the compression ratio of JPEG and JPEG2000 files should not be greater than 25 times.

4.3.2 Image quality

The quality of the output face image is determined by 5.1 in GA/T 1344-2016.According to the different face image library deployed, it conforms to GA 461-the frontal photograph requirements of Chapter 4 in 2004, 4.2 in GA/T 1180-2014 and 6.1 in GA/T 706-2007.

a) The distance between the two eyes. the registered face image should meet the 60 pixel requirement of 4.1.1 in GA/T 922.2-2011, and the face image should be recognized Meet the 30 pixel requirements of 4.2.1 in GA/T 922.2-2011;

b) Face pitch angle. The registered face image should meet the requirements of GA/T 922.2-2011 4.1.3 not greater than ±10°, and recognize the face the image should meet the requirements of GA/T 922.2-2011 in 4.2.2 not greater than ±20°, and there should be auxiliary measures to ensure that the face angle meets the requirements Claim;

c) Distortion rate eta. not more than 1%;

d) Grayscale. the dynamic grayscale range is not less than 180 levels;

e) Clarity. The face is clear, without obvious tailing, jitter and other motion blur;

f) Noise. The image has no obvious noise;

g) Others. Other requirements specified in Chapter 4 of GA/T 922.2-2011.

4.3.3 Image processing

The post-processing of the captured image in terms of color and brightness is in accordance with the following requirements.

a) Color adjustment. The color of the image can be adjusted appropriately until the skin color of the face is natural and true. When the image is seriously color cast, it should not be forcibly adjusted its color should be recollected after adjusting the white balance;

b) Brightness and highlight processing. The brightness can be adjusted appropriately until the skin color of the face is natural and true, and the image is seriously underexposed or overexposed at this time, the brightness should not be forcibly adjusted, and the exposure parameters of the equipment should be adjusted and then collected again.

5.1 Collection environment

5.1.1 Installation location

The installation locations of different dynamic acquisition equipment for testing are as follows.

a) Measure the measured distance L, installation height H1 and pitch angle A of the dynamic collection device from the collection object, refer to Table A.2 and Table A.3 and Table A.4, judge whether it meets the requirements of a) and b) in 4.1.1;

b) Observe the installation height H1 of the dynamic acquisition equipment in the entrance and exit control scene from the ground, and judge whether it meets the requirements in 4.1.1 c).

5.1.2 Ambient lighting

Observe the lighting conditions of the area around the collection object and the face area, and use a visible light meter to test the area around the collection object and the face Area light intensity, judge whether it meets the requirements of 4.1.2.

5.2 Acquisition equipment

5.2.1 Video/Camera

View the camera/camera inspection report installed on site for dynamic acquisition, check the consistency of the acquisition equipment model and the inspection report, Verify the number of pixels of the image sensor, shutter adjustment speed, and sampling frame rate indicators, identify the optimal selection of face images between frames and index face images with both portraits Like output function, judge whether it meets the requirements of a), b), c) and d) in 4.2.1.

5.2.2 Lens

View the inspection report of the lens equipped with the dynamic acquisition equipment installed on the site, check the consistency of the lens model and the inspection report, and verify the largest lens Aperture and focal length indicators, to determine whether they meet the requirements of a), b) and c) in 4.2.2.

5.2.3 Interface

Visually inspect the physical interface to determine whether it meets the requirements in 4.2.3 a).

Send the "device initialization function", "device connection function", etc. of the 11 face collection functions of GA/T 1326-2017 to the collection device no less than 3 random functions, check the command interface of the dynamic acquisition device, and judge whether it meets the requirements in 4.2.3 b).

5.3 Acquiring images

5.3.1 File format

Check the output file format as follows.

a) Check the compression encoding type of the face video file under the specified storage path to determine whether it meets the requirements of a) in 4.3.1;

b) Check the output format of the face image file under the specified storage path, and calculate the ratio of the file length before compression to the file length after compression Value, to determine whether it meets the requirements of b) in 4.3.1.

5.3.2 Image quality

Test the image quality as follows.

a) Collect a front view of the object in the field of view space at the actual measurement distance L from the face recognition video image acquisition device.

According to the face image, test the number of pixels between the eyes of the collected object's face image and the pitch angle A to determine whether it meets the requirements in 4.3.2

a) and b) requirements;

b) Collect a standard test card M image, make it fill the high-definition display, calculate according to the formula (B.1) in Appendix B, and judge it to be Whether it meets the requirements of c) in 4.3.2;

c) Collect a standard test card M image, observe the dynamic gray range of the standard test card M image histogram, and judge whether it meets 4.3.2 d) requirements;

d) Visually inspect the sharpness and noise of the collected face image in 5.3.2a), and judge whether it meets the requirements of e), f) and g) in 4.3.2.

5.3.3 Image processing

Visually inspect the color adjustment, brightness and highlight processing effect of the post-processed image to determine whether it meets the requirements of a) and b) in 4.3.3.