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This is amazing!Have you used the on board USB on some pics to interface with a USB cam?Give us details man!
Quote from: voyager2 on September 18, 2010, 09:36:25 PMThis is amazing!Have you used the on board USB on some pics to interface with a USB cam?Give us details man!Thanks you liked it.No, there is no USB CAM, instead off, I start from 0, thinking about how a video system recongnition can be done...I used to have one of these economic wireless cameras. I opened it and got out de CCD sensor, it was an omnivision OV7910...Next, I had to find the datasheet in internet of this cam. What I found is that this image sensor is 100% analog, but, it can be configured by I2C, to output analog RGB in three pins instead of NTSC.I had read how CMUCAM does the job, it compares, pixel by pixel (3 bytes each) vs the range of color (window color) you are looking for. It takes so long and too much power procesor, because comparations are in digital domain. So I though "why not compare the analog RGB values, using analog comparators, such as LM339... It's the same principle but in analog domain...." So, I used 3 analog window comparators, each one conected to an ouput color (R G or B), and to digital potentiometers... What I got is the same way procesing colors, but in real time, there is no "cycles clock". The AND ouput of the 3 windows comparators tell me two things: 0 = no color wanted, 1 = this pixel has the color that you are looking for. This single bit, is the input of the pic, so, the microcontroler, just have to sincronize with HSYNC and VSYNC and process this only bit.It is tricky, doesn't it?But in fact, every CCD sensor, is analog by nature, then they convert it to a digital domain, so this is not a loss process, thinking that all images in the sensor are analog by nature, I only simplified very much the job of the microprocesor...So, I got this RGB path ok? then, I had to "reencoded" it to NTSC using an AD725 from analog devices... but, by the way, I put 3 muxes in the RGB path, so, it's very easy to do a video overlay, wich I use to show what de camera is seeingI hope you understand this explanation, sorry again for my english, but it's usefull to me to practice my writingregards.
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