All the IPB functions can be adjusted by the camera designer via the system bus. One function is Bayer to RGB conversion. Data captured by the sensors in the Bayer code is converted into RGB. Virtually all CCDs optimize color and spatial resolution by using the Bayer code.
Another function is color correction, which includes white balancing. This compensates for the red, green, and blue shifts that naturally occur because of several reasons. For example, skin tones tend to turn bluer under fluorescent light, or redder under sunlight or tungsten light. Most cameras perform color correction in software. NuCore, though, performed color correction in hardware so that it could be accomplished in record speed.
Also, color balancing has traditionally only been carried out in the digital domain. But, in the course of its pixel-by-pixel processing, the company has implemented color balancing in analog in the NDX-1250. Then, the color is fine-tuned in this post-processing capability. The result is a very smooth, seamless dynamic color range.
The purpose of gamma correction is to correct an image, adjusting the brightness of the picture by utilizing a nonlinear conversion of the brightness-darkness spectrum. Many camera designers are using this feature to fine-tune the tone control.
Though unusual in a chip set, the skin-tone compensation feature ensures that the tones appear natural to the viewer. Furthermore, edge enhancement makes fine-line edges sharper and crisper. Plus, false-color suppression compensates for color distortions that are most likely to appear along thin objects, such as a hair, which may be no more than a single pixel in width.
Yet another function is highlight detection. Adaptive filtering is used to counteract washout that can occur in some regions of an image, providing better definition.
Finally, YC conversion changes the RGB coding to YC (luminance and chrominance). This is essential for compatibility with NTSC, PAL, and JPEG formats.
After leaving the image-processing and enhancement stages, the image can be captured directly for a high-quality image. If a large number of images are going to be stored in memory, the JPEG image compression algorithm can be applied. This is performed with user-selected levels of image compression. Also, images can be acquired in rapid succession and stored as moving images by employing the motion JPEG standard. As an alternative to JPEG, raw-imaged data can be sent out through the compact flash that, in turn, can be connected to an external codec of either the DV or MPEG variety.
A built-in, professional-quality video encoder enables the user to preview the captured images on television. The video encoder supports the NTSC and PAL standards. Additionally, the "Gen Lock" clock synchronization function is built in for designers of professional video cameras.
An embedded controller interface provides access to signals for system-level functions that don't necessarily have to be executed in real time. Suitable for this application are the familiar Hitachi SH processor and the Fujitsu Sparc-lite processor.
The DMA controller in the SiP manages the allocation of memory bandwidth and the flow of data. The USB interface allows the user to capture images directly on a PC. Likewise, the ATA hard-disk-drive interface enables capturing images in a movie mode.
Power consumption for the SiP-1250 is less than 450 mW at 50 Mpixels/s and less than 270 mW at 30 Mpixels/s. Because the processing time is so short, a 3-Mpixel image can be fully processed with less than 30 mW-s of battery energy consumed by the chip set. This compares with the 240 to 360 mW-s for alternative chips on the market.
A robust camera-system-level API is supplied with the chip set, based on the mItron 3.0 embedded operating system. Plus, NuCore supplies digital-camera APIs, like zoom control, flash control, and button control.
Price & Availability
The NC-1250 front-end device is mounted in a 48-lead surface-mount TQFP. Sample quantities are available now. The price is $15 each in quantities of 100,000.
The SiP-1250 smart image processor is mounted in a 256-ball surface-mount BGA package. Sample quantities will be available in November. The devices cost $40 each in quantities of 100,000.
NuCore Technology Inc., 2880 Bowers Ave., Santa Clara, CA 95051; (408) 919-1820; fax (408) 969-2688; www.nucoretech.com.