Jarkko Viinikanoja

Integrated measurement system for miniature camera modules

Particularly for miniature camera modules, manufactured in high volumes, characterization and measurement approaches are needed that provide information on camera key properties efficiently. An integrated measurement system named has been developed that uses images taken on specifically designed test chart targets, which are then automatically analysed by software. The chart combines target elements for measurement of optoelectronic conversion function, resolution, noise, uniformity, distortion and colour reproduction. The software applies machine vision to recognize the various target elements from the images, and to register analysis locations properly. The actual analysis methods conform with existing standards. The software includes graphical user interface, and in addition to the automatic analysis, also user-defined analysis can be flexibly done. The software supports modifications in the chart layout, batch analysis of images and storing the results in spreadsheet report format.

Cameras in mobile phones

One of the fastest growing markets in consumer markets today are camera phones. During past few years total volume has been growing fast and today millions of mobile phones with camera will be sold. At the same time resolution and functionality of the cameras has been growing from CIF towards DSC level. From camera point of view the mobile world is an extremely challenging field. Cameras should have good image quality but in small size. They also need to be reliable and their construction should be suitable for mass manufacturing. All components of the imaging chain should be well optimized in this environment. Image quality and usability are the most important parameters to user. The current trend of adding more megapixels to cameras and at the same time using smaller pixels is affecting both. On the other hand reliability and miniaturization are key drivers for product development as well as the cost. In optimized solution all parameters are in balance but the process of finding the right trade-offs is not an easy task. In this paper trade-offs related to optics and their effects to image quality and usability of cameras are discussed. Key development areas from mobile phone camera point of view are also listed.