Patent Application
20080058020
These and other aspects of the mobile device according to the invention will become apparent from and will be elucidated with respect to the implementations and embodiments described hereinafter and with reference to the accompanying drawings, wherein:
This mobile device 100 is arranged to acquire input images and to transmit these input images to other devices. In order to determine whether the appropriate input images are and/or will be acquired, the user is provided with display images which are related to the acquired input images. That means that the mobile device can operate in a so-called viewfinder mode.
An important function of the mobile device 100 is the temporal up-conversion of input images into display images. Temporal up-conversion, or picture rate conversion is e.g. disclosed in chapter 4 of the book “Video processing for multimedia systems”, by G. de Haan (ISBN: 90-9014015-, Eindhoven September 2000). Preferably, the up-conversion is motion compensated in order to get smooth motion portrayal. In section 4.3.1 of the cited book is a motion compensated picture repetition method disclosed which results in a minimum latency. For view finding this type of up-conversion is preferred.
Next some scenarios are discussed related to the control of the stream of image data from the acquisition, i.e. the integrated camera 106, to the display device 102. Suppose that the integrated camera 106 acquires input images with an acquisition frequency fA of e.g. 15 images per second. These input images are optionally processed and then a sequence of display images is provided to the display device 102. Each image of the sequence of display images is derived from a respective image of the sequence of input images. Hence, the display device 102 is displaying the sequence of display images with a display frequency of fD of 15 images per second. Assume that the motion detection unit or motion estimation unit, which is implemented in the image processing unit 104 determines that the subsequent input images of the sequence of input image are substantially mutually equal. That means that differences between the subsequent images are primarily based on noise. Then the integrated camera 106 is informed about this fact. As a consequence the integrated camera 106 reduces his acquisition frequency fA to e.g. 5 images per second. In order to remain at the display frequency fD of 15 images per second, the image processing unit 104 computes additional display images on basis of the acquired input images.
Alternatively, the motion detection unit or motion estimation unit determines that there is a substantial amount of motion. In that case the display frequency fD might be too low for a nice motion portrayal. Then a display frequency fD which is higher than 15 images per second, e.g. 25 or 50 images per second, is required. Without increasing the acquisition frequency fA this is achieved by means of temporal interpolation being performed by the image processing unit 104. In other words, on basis of the sequence of input images, comprising 15 input images belonging to a time period of 1 second, a sequence of display images is computed comprising e.g. 25 display images belonging to the time period of 1 second.
It will be clear that also images which are received by means of the data exchange unit 108 might be provided to the up-conversion unit, being implemented by the image processing unit 104, in order to compute an extended sequence of display images.
To summarize. In connection with
The control is based on comparing image content, e.g. motion detection or motion estimation of the acquired input images. Optionally the control is based on the input of the user. Therefore the mobile device optionally comprises a user interface to control the mobile device to make a trade-off between control of the image acquisition unit and the interpolation unit. The user can e.g. choose between high perceived image quality, moderate perceived image quality and low perceived image quality corresponding to respective amounts of energy consumption.
Alternatively the control is based on the available amount of energy.
- In the case of a relatively high energy level, i.e. amount of energy currently available, the display frequency fD might be relatively high, e.g. 25 or 50 mages per second. Also the acquisition frequency fA might be relatively high in that case, even equal to the display frequency fD.
In the case of an average energy level, the display frequency fD could be moderate, e.g. 15 images per second. The acquisition frequency fA might be equal to display frequency fD but preferably the acquisition frequency fA is lower than the display frequency fD, e.g. reduced to e.g.8 images per second.
In the case of a relatively low energy level, the display frequency fD should be relatively low, e.g. 5 or 10 images per second. The acquisition frequency fA might be even lower then the display frequency fD.
It will be clear that the control of the integrated camera 106, the image processing unit 104 and the display device 102 might differ from what is described in these examples. Other combinations of the acquisition frequency fA and the display frequency fD are also possible for different energy levels.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be constructed as limiting the claim. The word ‘comprising’ does not exclude the presence of elements or steps not listed in a claim. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several distinct elements and by means of a suitable programmed computer. In the unit claims enumerating several means, several of these means can be embodied by one and the same item of hardware.
| Number | Date | Country | Kind |
|---|---|---|---|
| 03102273.4 | Jul 2003 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/IB04/51217 | 7/14/2004 | WO | 00 | 1/20/2006 |
