Image Quality Testing
Image Quality Testing measures imaging performance of the product. Test can be done after product launch or during product development phase. Testing during product development helps to minimize Image Quality issues. Test report consists of objective IQ-metrics (key parameter indicator, KPI) and subjective analysis with recommendation how to improve Image Quality. Device under test is compared against reference device.
Image Quality Tests include:
- Still Image
- Image Stabilization
- Adaptive LED Flash test
- Photo Space Lab images and outdoor images
Still images are taken in Image Quality Laboratory including several test charts and illuminations. IQ KPI:s are measured to get objective numbers for color reproduction, shading, noise, resolution, sharpening, tone mapping, brightness, and distortion.
Video tests are performed with Image Engineering lightSTUDIO (with moving targets). Video resolution is measured from the stable frame and from the moving frames. Speed of the test chart can be controlled from 0 to 2 m/s. Convergence times of auto exposure and auto white balance are also measured.
Photo Space Lab is used for autofocus test. Images are captured under five different conditions from macro to Infinity distance. 100 images are taken from each content so totally 500 images. Pass/failure rates are reported which shows that in how many times AF has been working.
LB-800 light box is used to perform auto-exposure test. Totally 171 images are taken with different intensity levels from dark to bright. ISO values and exposure times are reported graphically as a function of intensity level.
Image stabilization test is done by attaching the product to a shaker device. Images are taken with and without shake under different illumination levels. Sharpness and noise is measured from the images. Test shows how well the image stabilizer works.
Image Engineering AF box and LED Panel V4 are used to perform latency tests. Shutter lag and shot- to-shot delays are measured.
Adaptive LED Flash test
Flash test is done under mixed light condition. Mannequin in the foreground is illuminated with camera flash and the objects on background with Philips Hue with color temperatures from 2000K to 6500K in 100K increments. White balance errors are measured from the gray cards located in foreground and background. Test shows how well the camera flash is adapting to the ambient light color.
Photo Space Lab images and outdoor images
Photo Space Laboratory simulates the conditions where people usually takes images. Current setup includes five test scenes: Bar, Livingroom, Play corner, City, and Golf green. Scenes are illuminated with different lights including tungsten, warm fluorescent, cold fluorescent, warm LED, cold LED, D50, and D65. Visual analysis is done for the captured images and compared to a reference product.
Valued Camera Experience
Valued Camera Experience (VCX) is an objective way to evaluate the performance of mobile cameras. VCX camera metrics consists of three parts: Image Quality, Camera Response Time, and Camera Motion control. One number, the VCX score, is reported as an output.