I have several ov7670 camera modules, some with Fifo. I have not started to get it working with my Arduino Due, but know the 790(!) posting thread on that subject:
Since I want to use camera for high speed autonomous robot control (Arduebot) I need high fps pictures sent to Due (the other Arduinos are no options because of lack of horse power). Pictures will be simple b&w, no high resolution is needed (80x60 or even 40x30 might be OK). Camera will be mounted sloped and take pictures from front of Arduebot (the "present") until a little ahead (in order to capture the "near future"):
So I think that Due+ov7670 will do the job needed.
Recently I bought Raspberry Pi Zero for 5$(+5$ shipping). It has a camera connector, but only for >35$ cameras. Yesterday I googled and found this really simple instruction on how to use a simple USB webcam with Raspberry Pi:
Wow, just ordered another "coprocessor", this time a "Quad-core Cortex-A7 Up to 1.2GHz" for 8$ !!
The website of FriendlyARM seems to be totally overloaded by the big demand, it took me 40(!) minutes to complete an order of "NanoPi Zero", so you need to be very patient if you will visit that website (>30 "Gateway Timeout" and other browser errors): http://nanopi.io/nanopi-neo.html
The "NanoPi NEO" features are unbelievable for 8$:
CPU: Allwinner H3, Quad-core Cortex-A7 Up to 1.2GHz
DDR3 RAM: 256MB[512MB sold out]
Connectivity: 10/100M Ethernet
USB Host: Type-A x 1, 2.54 mm pin x 2
MicroSD Slot x 1
MicroUSB: for data transmission and power input
Debug Serial Port: 4Pin, 2.54 mm pitch pin header
GPIO: 2.54mm pitch 36pin. It includes UART, SPI, I2C, IO etc
PCB Dimension: 40 x 40 mm
Power Supply: DC 5V/2A
OS/Software: u-boot and UbuntuCore
I did order two NanoPi Neo, with 7$ shipping for 23$ in total,
So this kind of "Arduino--(UART)--Pi" connection would allow Pi Zero and NanoPi Neo to be used as coprocessors for any Arduino. With 8$ NanoPi Neo and 2$ USB webcam this can be a 10$ camera coprocessor for Arduinos:
On the prototyping caterpillar robot I use an Arduino Uno, therefore a level shifter was needed.
The other caterpillar robot in that thread (Arduecat) is based on Arduino Due and does not need level shifter.
90fps video taken from on robot Raspberry camera, so what you see is slowed down by factor 90/25=3.6: