fingerprint_mcu

Source code: fingerprint_mcu.py

A factory test for the Fingerprint sensor.

Description

Tests that the fingerprint sensor is connected properly and has no defect by executing commands through the fingerprint micro-controller.

Internal references

• go/cros-fingerprint-factory-requirements#Documents

The testing procedures, such as (inverted) checkerboard and reset pixel, are defined in the MTS (Module Test Specification) and ITS (In-Device Test Specification) docs. By default, the pytest uses the acceptance criteria of ITS.

Test Procedure

1. The sensor must not be pressed until the test shows instruction on the UI.

2. Test performs automated test (e.g. pixel median) without user interaction.

3. If number_of_manual_captures is not 0, then an operator or a fixture must pressed a rubber finger or a real finger against the sensor.

4. If rubber_finger_present is true, then an operator or a fixture must pressed a rubber finger against the sensor to calculate the SNR.

5. The test fails if any of above three tests is marked as failed.

Dependency

The pytest supposes that the system as a fingerprint MCU exposed through the kernel cros_ec driver as /dev/cros_fp.

When available, it uses the vendor ‘libfputils’ shared library and its Python helper to display the captured image and compute the image quality signal-to-noise ratio.

Examples

Minimum runnable example to check if the fingerprint sensor is connected properly and fits the default quality settings:

{
  "pytest_name": "fingerprint_mcu",
  "label": "Fingerprint Sensor test",
  "run_if": "device.component.has_fingerprint",
  "related_components": [
    "test_tags.TestCategory.FINGERPRINT_SENSOR"
  ],
  "args": {
    "fpframe_retry_count": 2
  }
}

To check if the sensor has at most 10 dead pixels, with bounds for the pixel grayscale median values and finger detection zones, add this in test list:

{
  "pytest_name": "fingerprint_mcu",
  "label": "Fingerprint Sensor test plus pixel median test for Dartmonkey",
  "run_if": "device.component.has_fingerprint",
  "related_components": [
    "test_tags.TestCategory.FINGERPRINT_SENSOR"
  ],
  "args": {
    "fpframe_retry_count": 2,
    "max_dead_pixels": 10,
    "pixel_median": {
      "cb_type1": [
        180,
        220
      ],
      "cb_type2": [
        80,
        120
      ],
      "icb_type1": [
        15,
        70
      ],
      "icb_type2": [
        155,
        210
      ]
    },
    "detect_zones": [
      [
        8,
        16,
        15,
        23
      ],
      [
        24,
        16,
        31,
        23
      ],
      [
        40,
        16,
        47,
        23
      ],
      [
        8,
        66,
        15,
        73
      ],
      [
        24,
        66,
        31,
        73
      ],
      [
        40,
        66,
        47,
        73
      ],
      [
        8,
        118,
        15,
        125
      ],
      [
        24,
        118,
        31,
        125
      ],
      [
        40,
        118,
        47,
        125
      ],
      [
        8,
        168,
        15,
        175
      ],
      [
        24,
        168,
        31,
        175
      ],
      [
        40,
        168,
        47,
        175
      ]
    ]
  }
}

To show 10 captures on the screen:

{
  "pytest_name": "fingerprint_mcu",
  "label": "Fingerprint Sensor test plus manual test",
  "run_if": "device.component.has_fingerprint",
  "related_components": [
    "test_tags.TestCategory.FINGERPRINT_SENSOR"
  ],
  "args": {
    "fpframe_retry_count": 2,
    "number_of_manual_captures": 10
  }
}

To test SNR value with a rubber stamp. Only work for Dartmonkey, see b/180757318 for more info:

{
  "pytest_name": "fingerprint_mcu",
  "label": "Fingerprint Sensor test plus rubber stamper test",
  "run_if": "device.component.has_fingerprint",
  "related_components": [
    "test_tags.TestCategory.FINGERPRINT_SENSOR"
  ],
  "args": {
    "fpframe_retry_count": 2,
    "rubber_finger_present": true
  }
}

Test Arguments

Name	Type	Description
max_dead_pixels	int	(optional; default: 10) The maximum number of dead pixels on the fingerprint sensor.
max_dead_detect_pixels	int	(optional; default: 0) The maximum number of dead pixels in the detection zone.
max_pixel_dev	int	(optional; default: 35) The maximum deviation from the median for a pixel of a given type.
pixel_median	dict	(optional; default: {}) Keys: “(cb|icb)_(type1|type2)”, Values: a list of [minimum, maximum] Range constraints of the pixel median value of the checkerboards.
detect_zones	list	(optional; default: []) a list of rectangles [x1, y1, x2, y2] defining the finger detection zones on the sensor.
min_snr	float	(optional; default: 0.0) The minimum signal-to-noise ratio for the image quality.
rubber_finger_present	bool	(optional; default: False) A Rubber finger is pressed against the sensor for quality testing.
max_reset_pixel_dev	int	(optional; default: 65) The maximum deviation from the median per column for a pixel from test reset image.
max_error_reset_pixels	int	(optional; default: 5) The maximum number of error pixels in the test_reset image.
fpframe_retry_count	int	(optional; default: 0) The maximum number of retry for fpframe.
number_of_manual_captures	int	(optional; default: 0) The number of manual captures operators take. If it is not zero then the operator must manually judge pass or fail.
manual_test_timeout_secs	float	(optional; default: 5.0) The timeout of captures in seconds.