Usually, we judge the quality of mobile phone cameras by checking if there are visible faults such as black screen display, large black spots on the lens, automatic restart of the device when using the camera function. If these problems do not exist, we could probably say that the quality of the camera is ideal. However, there are more criteria to judge whether a camera is functioning well, that is, we also need to test the quality of the image. This blog will show you how to select a high-quality camera for your mobile through testing.
Before testing, we need to replace the damaged camera using simple procedures.
Tools Required
Screen disassemble set*1,
Camera*1,
Waterproof glue (required for some models)*1,
Test card*3,
Computer test software
Replacement Procedures
1. Disassemble the screen.
2. Remove and reinstall the camera.
Attention: when removing or installing is carried out, do not touch the camera cable next to the screws.
3. Install the screen.
4. Perform the testing.
Conventional Visual Inspection:
1.
Signal Test: Turn on the shooting function. If there is no reaction, it’s just like there is no shooting device. If this situation happens, the camera is regarded as unqualified.
2.
Light Spot Inspect: Check if there are individual light spots appear when shooting contrasts with black background. If this situation happens, the camera is regarded as unqualified.
3.
Dark Spot Inspect: Check if individual dark spots appear when shooting contrasts with white background. If this situation happens, the camera is regarded as unqualified.
4.
Image Test: Turn on the shooting function. Check if local or whole undistinguishable lines appear when shooting objects with obvious lines. If this situation happens, the camera is regarded as unqualified.
If the object being shot is undetectable, the camera is also regarded as unqualified.
In order to provide customers with high-quality cameras, we also use test cards to test the samples as follows:
Conventional Tests with Test Cards:
1.
Out of Focus Test
Test method: Put the mobile phone and the test card at 90 degrees, aim at the surface of the target, and observe whether the blurring boundary is as wide as the top and bottom. If there is a difference in the offset, there is out of focus.
In the case of normal optical distortion, the sample lines taken by the camera should be close to straight. If a bad optical distortion occurs, the following phenomenon appears:
- Resolution and Definition Test
This test requires Olympus Hyres 3.1. Please download and perform the test according to the following steps.
Procedures of the test:
i. Download Olympus Hyres3.1. You may download the software via this link:
ii. Click the “Trim” button → select “Open” → open the jpeg picture of the shot → select 9 on the wedge type, indicate that the test pattern to be calculated is the 500-2000 line test pattern of 9 parallel lines.
iii. Click on the “Execute” button
iv. The test results are displayed in the result box.
The picture shows the resolution of the camera of the iPhone 6s, and the detection result is displayed as 1894 lines.
The higher the resolution, the higher the definition.
- Noise Performance and Dynamic Range Test
Noise performance is affected by the time of exposure and operating temperature, which in turn varies with noise performance.
The larger the dynamic range, the richer the details of the dark parts and the details of the light spots that can be recorded simultaneously by the camera. The pictures taken are thus closer to the original color and they become clearer.
We test the capabilities like the resolution, out of focus and other performances repeatedly, and observe the values/statuses of each tested performance to see whether they are lower than the minimum required standard. If the results are lower than the minimum required standard, it means that the noise performance and dynamic range are poor.
The specific evaluation criteria depend on the performance of each test and its standard values.
Have you successfully learned the above test methods? Start testing your camera.
For more detail, please watch the video.
