Currently on the market most of the image acquisition system is based on DSP. This image acquisition system's high cost, great power consumption, and volume restriction is not suitable for some simple applications. So in this project we will be using S3C2440 along with embedded Linux. S3C2440 is being manufactured by Samsung and is a RISC microprocessor based on ARM920T.The maximum frequency can reach 533MHz. In this project we will be using an OV9650 Color CMOS SXGA (1.3 Mega Pixel) From Omni-Vision camera connected to ARM9. One Linux device driver will be responsible for the camera. For writing to the LCD, Linux has Frame Buffer. Frame Buffer is the device for user process to write directly to screen in Embedded Linux. In Linux Frame Buffer is an interface for the display device. It describes some display device as a buffer and allows applications to access the graphics device through its defined interface without care about the specific hardware details. We will also be using Video4Linux. Video4Linux or V4L is a video capture application programming interface for Linux. V4L is divided into two layers. The bottom is the audio and video equipment driver in the kernel, and the upper provides systern with some API. Image data can be reconstructed through JPEG decoding. JPEG image files are divided into two parts: marking segment and compressing data. Marking segment include length, width, color information's, quantization table, Huffman table and other important information's of the image. Different informations store at different marking segment. JPEG image decoding process needs to extract the various of needed information in the marking segment, so as to facilitate decoding of compressed data. Finally the collected images transferred from JPEG format to RGB format is displayed on the LCD finally.
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