02.13.2008
ROHM has developed a TV encoder LSI integrating unique hardware image correction AIE (Adaptive Image Enhancer) that offers unprecedented high precision, discrete correction of images in real time, making it ideal for surveillance cameras, home security systems, automobile drive recorders and vehicle mounted cameras, where visibility is often poor due to changing ambient conditions, extreme backlighting, or darkness.
The BU6520KV rapidly analyzes input images, divides the images into areas using unique algorithms, extracts the optimum brightness and color correction parameters for each area, and conducts real-time, high-speed image correction. The brightness of dark and bright areas are adjusted proportionally, resulting in visibility similar to the human eye.
All required settings such as NTSC/PAL values, sampling frequency, and gamma values, can be stored in and read from an external EEPROM, enabling operation without a microcontroller– unlike conventional TV encoder ICs.
Additional features include support for composite and CCIR601/656 component outputs, wireless LAN compatibility, and access of image correction data via external EEPROM, enabling replacement in existing systems without the need for hardware or software modification.
Samples are available (sample price: 14US$) with mass production scheduled for February 2008.
- Unique AIE core utilized for optimum image correction
- Clear images with visibility close to the human eye
- Color correction function built-in for brilliant color quality
- Integrated edge enhancement and gamma filters further improve visibility
- CCIR601/656-compatible input/output
- Built-in TV encoder supports NTSC/PAL (27MHz/8fsec/28.375MHz) composite output
- AIE/TV encoder settings downloadable automatically from EEPROM, enabling use without microcontroller
- VQFP48C package
Also called a video encoder, this device converts digital image signals output from a camera or MPEG decoder to analog television (video) signals.
Camera sensors are broadly classified into two types, CCD and CMOS. CCD sensors are widely used in digital video cameras and digital still cameras and are characterized by having higher sensitivity and lower noise than CMOS sensors. CMOS sensors, on the other hand, are cheaper to produce and are generally smaller, resulting in lower power consumption.
The major function of a camera DSP is Bayer-RGB conversion, where Bayer pattern raw data (signal array) from a CMOS or CCD sensor is converted to individual RGB arrays for each pixel. Optional functions include gamma correction, auto gain control (brightness correction), auto white balance, and auto focus.
These are digital (component) video format standards. CCIR656 combines the horizontal and vertical synchronization components in the clock, while CCIR601 separates the two.
A process whereby contour portions of an image and density gradients are sharpened, resulting in better image quality.
- Gamma Correction (filter)
A characteristic of CRT and LCD displays is that display brightness does not rise in direct proportion to increases in the input voltage (the rise is curvilinear). This is solved using gamma correction. In liquid crystal display monitors correction is conducted so that it has the same display characteristics as a CRT (in order to maintain compatibility with CRTs). Images are made easier to see by adjusting gradation in dark areas where the image become completely black or in bright areas that become completely white, or in delicate intermediate regions where color reproduction is incorrect.
NTSC is an analog image signal format used for television broadcasts in Japan, Taiwan, Korea, Philippines, and various countries in Central and South America. It specifies a display of 525 horizontal scan lines at 30 frames/60 fields per second interlaced, meaning half the image is displayed per pass (every other scan line). PAL is an analog image signal format adopted in Europe, most ASEAN countries, most of the Middle East, parts of Africa, Brazil, Australia, and several other countries. It is an interlaced method stipulating 625 horizontal scan lines displayed at 25 frames/50 fields per second. Although the vertical resolution is higher than NTSC, the frame rate is proportionally lower.
BU6520KV datasheet
